5725A
Amplifier
Instruction Manual
January 1989 Rev. 7, 06/02
© 1993, 2002 Fluke Corporation. All rights reserved. Specifications are subject to change without notice.
All product names are trademarks of their respective companies.
LIMITED WARRANTY AND LIMITATION OF LIABILITY
Each Fluke product is warranted to be free from defects in material and workmanship under normal use and
service. The warranty period is one year and begins on the date of shipment. Parts, product repairs, and
services are warranted for 90 days. This warranty extends only to the original buyer or end-user customer of
a Fluke authorized reseller, and does not apply to fuses, disposable batteries, or to any product which, in
Fluke's opinion, has been misused, altered, neglected, contaminated, or damaged by accident or abnormal
conditions of operation or handling. Fluke warrants that software will operate substantially in accordance with
its functional specifications for 90 days and that it has been properly recorded on non-defective media. Fluke
does not warrant that software will be error free or operate without interruption.
Fluke authorized resellers shall extend this warranty on new and unused products to end-user customers
only but have no authority to extend a greater or different warranty on behalf of Fluke. Warranty support is
available only if product is purchased through a Fluke authorized sales outlet or Buyer has paid the
applicable international price. Fluke reserves the right to invoice Buyer for importation costs of
repair/replacement parts when product purchased in one country is submitted for repair in another country.
Fluke's warranty obligation is limited, at Fluke's option, to refund of the purchase price, free of charge repair,
or replacement of a defective product which is returned to a Fluke authorized service center within the
warranty period.
To obtain warranty service, contact your nearest Fluke authorized service center to obtain return
authorization information, then send the product to that service center, with a description of the difficulty,
postage and insurance prepaid (FOB Destination). Fluke assumes no risk for damage in transit. Following
warranty repair, the product will be returned to Buyer, transportation prepaid (FOB Destination). If Fluke
determines that failure was caused by neglect, misuse, contamination, alteration, accident, or abnormal
condition of operation or handling, including overvoltage failures caused by use outside the product’s
specified rating, or normal wear and tear of mechanical components, Fluke will provide an estimate of repair
costs and obtain authorization before commencing the work. Following repair, the product will be returned to
the Buyer transportation prepaid and the Buyer will be billed for the repair and return transportation charges
(FOB Shipping Point).
THIS WARRANTY IS BUYER'S SOLE AND EXCLUSIVE REMEDY AND IS IN LIEU OF ALL OTHER
WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY IMPLIED WARRANTY
OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. FLUKE SHALL NOT BE LIABLE
FOR ANY SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES OR LOSSES,
INCLUDING LOSS OF DATA, ARISING FROM ANY CAUSE OR THEORY.
Since some countries or states do not allow limitation of the term of an implied warranty, or exclusion or
limitation of incidental or consequential damages, the limitations and exclusions of this warranty may not
apply to every buyer. If any provision of this Warranty is held invalid or unenforceable by a court or other
decision-maker of competent jurisdiction, such holding will not affect the validity or enforceability of any other
provision.
Fluke Corporation
P.O. Box 9090
Everett, WA 98206-9090
U.S.A.
Fluke Europe B.V.
P.O. Box 1186
5602 BD Eindhoven
The Netherlands
11/99
To register your product online, visit register.fluke.com
Table of Contents
Chapter Title Page
1 Introduction and Specifications ......................................................... 1-1
1-1. Introduction ........................................................................................... 1-3
1-2. Where to Go From Here ....................................................................... 1-4
1-3. How to Use the Manuals ....................................................................... 1-5
1-4. 5725A Getting Started Manual ......................................................... 1-5
1-5. 5725A Instruction Manual ................................................................ 1-5
1-6. 5700A/5720A Series II Manual Set ................................................. 1-5
1-7. 5700A/5720A Series II Operator Manual ........................................ 1-5
1-8. 5700A/5720A Series II Operator Reference Guide .......................... 1-5
1-9. 5700A/5720A Series II Remote Programming Reference Guide ..... 1-6
1-10. 5700A/5720A Series II Service Manual ........................................... 1-6
1-11. Specifications ........................................................................................ 1-6
1-12. DC Voltage Specifications .................................................................... 1-7
1-13. AC Voltage Specifications .................................................................... 1-10
1-14. Resistance Specifications ...................................................................... 1-16
1-15. DC Current Specifications .................................................................... 1-20
1-16. AC Current Specifications .................................................................... 1-23
1-17. Wideband AC Voltage (Option 5700-03) Specifications ..................... 1-28
1-18. General Specifications .......................................................................... 1-29
1-19. Auxiliary Amplifier Specifications ....................................................... 1-30
2 Installation ........................................................................................... 2-1
2-1. Introduction ........................................................................................... 2-3
2-2. Unpacking and Inspection .................................................................... 2-3
2-3. Service Information .............................................................................. 2-5
2-4. Placement and Rack Mounting ............................................................. 2-5
2-5. Cooling Considerations......................................................................... 2-5
2-6. Connecting to the 5700A Calibrator ..................................................... 2-6
2-7. Selecting Line Voltage .......................................................................... 2-7
2-8. Accessing the Fuse ................................................................................ 2-8
2-9. Connecting to Line Power .................................................................... 2-9
3 Operating Notes................................................................................... 3-1
3-1. Introduction ........................................................................................... 3-3
3-2. Front Panel Features ............................................................................. 3-4
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5725A
Instruction Manual
3-3. Rear Panel Features .............................................................................. 3-6
3-4. Turning on the 5725A Amplifier .......................................................... 3-8
3-5. Warm Up............................................................................................... 3-8
3-6. 5725A Operating Functions and Modes ............................................... 3-9
3-7. Standby ............................................................................................. 3-9
3-8. Voltage Standby ............................................................................... 3-10
3-9. Current Standby ................................................................................ 3-11
3-10. Voltage Operate ................................................................................ 3-12
3-11. Current Operate ................................................................................ 3-13
3-12. Conditions That Activate the 5725A .................................................... 3-14
4 Theory of Operation ............................................................................ 4-1
4-1. Introduction ...................................................................................... 4-3
4-2. Overall Functional Description ........................................................ 4-3
4-3. 1100V AC Range Functional Description ........................................ 4-5
4-4. 11A Range Functional Description .................................................. 4-6
4-5. Operation in the 11A DC Range .................................................. 4-7
4-6. Operation in the 11A AC Range .................................................. 4-7
4-7. Voltage and Current Standby Modes ............................................... 4-7
4-8. Voltage Standby ........................................................................... 4-7
4-9. Current Standby ........................................................................... 4-7
4-10. How the 5700A and 5725A Communicate ....................................... 4-8
4-11. Description of the Out-Guard Lines (5725A Side) ...................... 4-8
4-12. Description of the In-Guard Lines ............................................... 4-9
4-13. Functional Summaries by Assembly ................................................ 4-10
4-14. Detailed Circuit Description ............................................................. 4-11
4-15.
Interconnect Assembly (A1) ............................................................. 4-11
4-16. Power Supply Assembly (A4) .......................................................... 4-12
4-17. High Voltage Supply Section ....................................................... 4-13
4-18. Switching Section ........................................................................ 4-14
4-19. Current-Limit Section .................................................................. 4-15
4-20. System Supply Section ................................................................. 4-15
4-21. Fan Supply Section ...................................................................... 4-16
4-22. Digital Assembly (A5) ..................................................................... 4-16
4-23. Microcomputer ............................................................................. 4-16
4-24. External RAM. ............................................................................. 4-16
4-25. External ROM .............................................................................. 4-16
4-26. EEROM ........................................................................................ 4-18
4-27. Data Latch .................................................................................... 4-18
4-28. Strobe Lines ................................................................................. 4-18
4-29. Led Driver .................................................................................... 4-18
4-30. Optoisolator Link ......................................................................... 4-18
4-31. Break-Detect Circuitry ................................................................. 4-18
4-32. Power Up and Reset Circuitry ...................................................... 4-19
4-33. Watchdog Timer........................................................................... 4-19
4-34. Current Amplifier Assembly (A2) .................................................... 4-19
4-35. Error Amplifier Section ................................................................ 4-21
4-36. Output Stage Section .................................................................... 4-22
4-37. Monitor Section ............................................................................ 4-22
4-38. Control and Switching Section..................................................... 4-23
4-39. Power Supply Section .................................................................. 4-23
4-40. High Voltage Amplifier (A3) ........................................................... 4-24
4-41. Input Amplifier ............................................................................ 4-24
4-42. Integrator ...................................................................................... 4-26
ii
4-43. Window Comparator .................................................................... 4-26
4-44. Input Clamp .................................................................................. 4-26
4-45. Transconductance and Cascode Stage .......................................... 4-27
4-46. Midstage ....................................................................................... 4-27
4-47. Midstage -400V Filter .................................................................. 4-27
4-48. High Voltage Heat Sink Assemblies ............................................ 4-27
4-49. Autobias Current Source .............................................................. 4-28
4-50. Autobias Sense Circuit ................................................................. 4-28
4-51. High Voltage Amplifier Feedback ............................................... 4-29
4-52. Signal Transformers ..................................................................... 4-29
4-53. Temperature Monitoring .............................................................. 4-29
4-54. High Voltage Sense Assembly (A6) ................................................. 4-30
4-55. Sense Amplifier Section ............................................................... 4-32
4-56. Analog Monitor Section ............................................................... 4-34
4-57. Serial Interface/Guard Crossing Section ...................................... 4-35
4-58. Analog Input Switching Section .................................................. 4-35
4-59. Control Section ............................................................................ 4-36
4-60. AC Line Voltage Selection Section ............................................. 4-37
5 Calibration and Verification ................................................................ 5-1
Contents (continued)
5-1. Introduction ........................................................................................... 5-3
5-2. Where to Find Further Information ...................................................... 5-3
6 Maintenance ......................................................................................... 6-1
6-1. Introduction ........................................................................................... 6-3
6-2. Replacing the Fuse ................................................................................ 6-3
6-3. Cleaning the Air Filter .......................................................................... 6-4
6-4. General Cleaning .................................................................................. 6-5
Cleaning PCA's ..................................................................................... 6-5
6-5.
6-6. Access Procedures ................................................................................ 6-6
6-7. Initial Access Procedure ................................................................... 6-7
6-8. Accessing the Power Supply Assembly (A4) ................................... 6-9
6-9. Accessing the Digital Assembly (A5) .............................................. 6-9
6-10. Accessing the Current Amplifier Assembly (A2) ............................ 6-11
6-11. Accessing the High Voltage Amplifier (A3) .................................... 6-12
6-12. Accessing the High Voltage Sense Assembly (A6) ......................... 6-13
6-13. Accessing the High Voltage Output Transistors .............................. 6-14
6-14. Accessing the Interconnect Assembly (A1) ..................................... 6-14
6-15. Enabling Front or Rear Binding Posts .................................................. 6-15
7 Troubleshooting .................................................................................. 7-1
7-1. Introduction ........................................................................................... 7-3
7-2. 5725A Fault Codes ............................................................................... 7-3
7-3. Self Diagnostics .................................................................................... 7-3
7-4. Manual Tests for Fault Isolation ........................................................... 7-6
7-5. Problems 1 or 2: Fault at Power-Up or When Entering
Voltage Standby ............................................................................... 7-7
7-6. Problem 3: Fault When Entering Voltage Operate ........................... 7-7
7-7. Problem 4: Fault When Entering Current Standby ........................... 7-8
7-8. Problem 5: Fault When Entering Current Operate ........................... 7-8
7-9. Reduced-Voltage Troubleshooting Mode ............................................. 7-8
7-10. Testing the Power Supply By Itself ...................................................... 7-9
iii
5725A
Instruction Manual
8 List of Replaceable Parts .................................................................... 8-1
8-1. Introduction ........................................................................................... 8-3
8-2. How to Obtain Parts .............................................................................. 8-3
8-3. Manual Status Information ................................................................... 8-3
8-4. Newer Instruments ................................................................................ 8-3
8-5. Service Centers ..................................................................................... 8-3
8-6. Parts Lists .............................................................................................. 8-4
9 Schematic Diagrams ........................................................................... 9-1
iv
List of Tables
Table Title Page
1-1. 5720A Series II DC Voltage Specifications: 99 % and 95 % Confidence Levels . 1-7
1-2. 5700A Series II DC Voltage Specifications: 99 % and 95 % Confidence Levels . 1-8
1-3. DC Voltage Secondary Performance Specifications and Operating
Characteristics ...................................................................................................... 1-9
1-4. 5720A Series II AC Voltage Specifications: 99 % Confidence Level ................... 1-10
1-5. 5720A Series II AC Voltage Specifications: 95 % Confidence Level ................... 1-11
1-6. 5700A Series II AC Voltage Specifications: 99 % Confidence Level ................... 1-12
1-7. 5700A Series II AC Voltage Specifications: 95 % Confidence Level ................... 1-13
1-8. AC Voltage Secondary Performance Specifications and Operating
Characteristics ...................................................................................................... 1-14
1-9. 5720A Series II Resistance Specifications: 99 % and 95 % Confidence Levels ... 1-16
1-10. 5700A Series II Resistance Specifications: 99 % and 95 % Confidence Levels ... 1-17
1-11. Resistance Secondary Performance Specifications and Operating
Characteristics ...................................................................................................... 1-18
1-12. Current Derating Factors ........................................................................................ 1-19
1-13. 5720A Series II DC Current Specifications: 99 % and 95 % Confidence Levels .. 1-20
1-14. 5700A Series II DC Current Specifications: 99 % and 95 % Confidence Levels .. 1-21
1-15. DC Current Secondary Performance Specifications and Operating
Characteristics ...................................................................................................... 1-22
1-16. 5720A Series II AC Current Specifications: 99 % Confidence Level ................... 1-23
1-17. 5720A Series II AC Current Specifications: 95 % Confidence Level ................... 1-24
1-18. 5700A Series II AC Current Specifications: 99 % Confidence Level ................... 1-25
1-19. 5700A Series II AC Current Specifications: 95 % Confidence Level ................... 1-26
1-20. AC Current Secondary Performance Specifications and Operating
Characteristics ...................................................................................................... 1-27
1-21. Wideband AC Voltage (Option 5700-03) Specifications ....................................... 1-28
2-1. Standard Equipment ............................................................................................... 2-3
2-2. Line Power Cord Types Available from Fluke ...................................................... 2-4
3-1. Front Panel Features ............................................................................................... 3-5
3-2. Rear Panel Features ................................................................................................ 3-7
4-1. Internal Fuse Data .................................................................................................. 4-13
4-2. Signal Transformer Usage ...................................................................................... 4-29
4-3. High-Quality Reference Name Destination ........................................................... 4-33
4-4. Signals Monitored by the Analog Monitor Section ............................................... 4-34
7-1. 5725A Fault Codes ................................................................................................. 7-4
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5725A
Instruction Manual
7-2. Analog Monitor Faults ........................................................................................... 7-7
8-1. Manual Status Information ..................................................................................... 8-4
8-2. Final Assembly ....................................................................................................... 8-4
8-3. A1 Interconnect PCA ............................................................................................. 8-15
8-4. A2 Current Amplifier PCA .................................................................................... 8-17
8-5. A3 High Voltage Amplifier PCA ........................................................................... 8-21
8-6. A4 Power Supply PCA ........................................................................................... 8-25
8-7. A5 Digital PCA ...................................................................................................... 8-29
8-8. A6 High Voltage Sense PCA ................................................................................. 8-31
8-9. A12 Transformer Enclosure Assembly .................................................................. 8-35
8-10. A30 Inductor PCA .................................................................................................. 8-40
vi
List of Figures
Figure Title Page
1-1. Volt-Hertz Capability ............................................................................................. 1-15
2-1. Line Power Cords Available for Fluke Instruments ............................................... 2-4
2-2. Correct Way to Dress Interface Cable .................................................................... 2-6
2-3. Line Power Label and Switch Location ................................................................. 2-7
2-4. Accessing the Fuse ................................................................................................. 2-8
3-1. Front Panel Features ............................................................................................... 3-4
3-2. Rear Panel Features ................................................................................................ 3-6
3-3. Standby Mode Indicator ......................................................................................... 3-9
3-4. Voltage Standby Mode ........................................................................................... 3-10
3-5. Current Standby Mode ........................................................................................... 3-11
3-6. Voltage Operate Mode ........................................................................................... 3-12
3-7. Current Operate Mode ............................................................................................ 3-13
4-2. Digital Assembly Block Diagram .......................................................................... 4-17
4-3. Current Amplifier Assembly Block Diagram......................................................... 4-20
4-4. High Voltage Amplifier Assembly Block Diagram .............................................. 4-25
4-5. High Voltage Sense Assembly Block Diagram ..................................................... 4-31
6-1. Accessing the Fuse ................................................................................................. 6-4
6-2. Accessing the Air Filter .......................................................................................... 6-5
6-3. Assembly Location Diagram .................................................................................. 6-6
6-4. Initial Access Procedure ......................................................................................... 6-8
6-5. Accessing the Digital Assembly ............................................................................ 6-10
6-6. Correct Way to Dress Cables ................................................................................. 6-12
6-7. Enabling Front or Rear Binding Posts.................................................................... 6-16
8-1. Final Assembly ....................................................................................................... 8-7
8-2. A1 Interconnect PCA ............................................................................................. 8-16
8-3. A2 Current Amplifier PCA .................................................................................... 8-20
8-4. A3 High Voltage Amplifier PCA ........................................................................... 8-24
8-5. A4 Power Supply PCA ........................................................................................... 8-28
8-6. A5 Digital PCA ...................................................................................................... 8-30
8-7. A6 High Voltage Sense PCA ................................................................................. 8-34
8-8. A12 Transformer Enclosure Assembly .................................................................. 8-36
9-1. A1 Interconnect PCA ............................................................................................. 9-3
9-2. A2 Current Amplifier PCA .................................................................................... 9-6
9-3. A3 High Voltage Amplifier PCA ........................................................................... 9-10
9-4. A4 Power Supply PCA ........................................................................................... 9-13
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5725A
Instruction Manual
9-5. A5 Digital PCA ...................................................................................................... 9-16
9-6. A6 High Voltage Sense PCA ................................................................................. 9-18
9-7. A12 Transformer Enclosure Assembly .................................................................. 9-23
viii
OPERATOR SAFETY
SUMMARY
WARNING
HIGH VOLTAGE
is used in the operation of this equipment
LETHAL VOLTAGE
may be present on the terminals, observe all safety precautions!
To avoid electrical shock hazard, the operator should not electrically
contact the output hi or sense hi binding posts. During operation, lethal
voltages of up to 1100V ac or dc may be present on these terminals.
Whenever the nature of the operation permits, keep one hand away from
equipment to reduce the hazard of current flowing thought vital organs of
the body.
Terms in this Manual
This instrument has been designed and tested in accordance with IEC Publication 348,
Safety Requirements for Electronic Measuring Apparatus. This manual contains information
and warnings which have to be followed by the user to ensure safe operation and to retain
the instrument in safe condition.
WWarning statements identify conditions or practices that could result in personal injury or
loss of life.
WCaution statements identify conditions or practices that could result in damage to the
equipment or other property.
Symbols Marked on Equipment
DANGER — High Voltage
Protective ground (earth) terminal
Attention — refer to the manual. This symbol indicates that information about
the usage of a feature is contained in the manua
Power Source
The 5725A is intended to operate from a power source that will not apply more than
264V ac rms between the supply conductors or between either supply conductor and
ground. A protective ground connection by way of the grounding conductor in the power
cord is essential for safe operation.
Use the Proper Fuse
To avoid fire hazard, use only the fuse specified on the line voltage selection switch
label, and which is identical in type voltage rating, and current rating.
Grounding the 5725A
l.
The 5725A is Safety Class I (grounded enclosure) instruments as defined in IEC 348.
The enclosure is grounded through the grounding conductor of the power cord. To avoid
electrical shock, plug the power cord into a properly wired earth grounded receptacle
before connecting anything to any of the 5725A or 5700A terminals. A protective ground
connection by way of the grounding conductor in the power cord is essential for safe
operation.
Use the Proper Power Cord
Use only the power cord and connector appropriate for proper operation of a 5725A in
your country.
Use only a power cord that is in good condition.
Refer cord and connector changes to qualified service personnel.
Do Not Operate in Explosive Atmospheres
To avoid explosion, do not operate the 5725A in an atmosphere of explosive gas.
Do Not Remove Cover
To avoid personal injury or death, do not remove the 5725A cover. Do not operate the
5725A without the cover properly installed. There are no user-serviceable parts inside
the 5725A, so there is no need for the operator to ever remove the cover.
Do Not Attempt to Operate if Protection May be Impaired
If the 5725A appears damaged or operates abnormally, protection may be impaired. Do
not attempt to operate it. When is doubt, have the instrument serviced.
SERVICING SAFETY
SUMMARY
FOR QUALIFIED SERVICE
PERSONNEL ONLY
Also refer to the preceding Operator Safety Summary
Do Not Service Alone
Do not perform internal service or adjustment of this product unless another person
capable of rendering first aid and resuscitation is present.
Use Care When Servicing With Power On
Dangerous voltage exist at many points inside this product. To avoid personal injury, do
not touch exposed connections and components while power is on.
Whenever the nature of the operation permits, keep one hand away from equipment to
reduce the hazard of current flowing through vital organs of the body.
Do not wear a grounded wrist strap while working on this product. A grounded wrist strap
increase the risk of current flowing through the body.
Disconnect power before removing protective panels, soldering, or replacing components.
High voltage may still be present even after disconnecting power.
FIRST AID FOR
ELECTRIC SHOCK
Free the Victim From the Live Conductor
Shut off high voltage at once and ground the circuit. If high voltage cannot be turned off
quickly, ground the circuit.
If the circuit cannot be broken or grounded, use a board, dry clothing, or other
nonconductor to free the victim.
Get Help!
Yell for help. Call an emergency number. Request medical assistance.
Never Accept Ordinary and General Tests for Death
Symptoms of electric shock may include unconsciousness, failure to breathe, absence of
pulse, pallor, and stiffness, and well as severe burns.
Treat the Victim
If the victim is not breathing, begin CPR or mouth-to-mouth resuscitation if you are
certified.
Chapter 1
Introduction and Specifications
Title Page
1-1. Introduction ........................................................................................... 1-3
1-2. Where to Go From Here ....................................................................... 1-4
1-3. How to Use the Manuals ....................................................................... 1-5
1-4. 5725A Getting Started Manual ......................................................... 1-5
1-5. 5725A Instruction Manual ................................................................ 1-5
1-6. 5700A/5720A Series II Manual Set ................................................. 1-5
1-7. 5700A/5720A Series II Operator Manual ........................................ 1-5
1-8. 5700A/5720A Series II Operator Reference Guide .......................... 1-5
1-9. 5700A/5720A Series II Remote Programming Reference Guide ..... 1-6
1-10. 5700A/5720A Series II Service Manual ........................................... 1-6
1-11. Specifications ........................................................................................ 1-6
1-12. DC Voltage Specifications .................................................................... 1-7
1-13. AC Voltage Specifications .................................................................... 1-10
1-14. Resistance Specifications ...................................................................... 1-16
1-15. DC Current Specifications .................................................................... 1-20
1-16. AC Current Specifications .................................................................... 1-23
1-17. Wideband AC Voltage (Option 5700-03) Specifications ..................... 1-28
1-18. General Specifications .......................................................................... 1-29
1-19. Auxiliary Amplifier Specifications ....................................................... 1-30
1-1
5725A
Instruction Manual
1-2
Introduction and Specifications
Introduction 1
1-1. Introduction
The Fluke 5725A Amplifier enhances the 5700A Calibrator in the ac voltage, ac current,
and dc current functions. The 5725A operates under complete control of the 5700A
through an interface cable supplied with the 5725A.
A diagram in the specifications tables at the end of this section illustrates the extended ac
volt-hertz product achieved by using a 5725A. Increased ac voltage load limits allow
using the 5700A Calibrator in systems with long cables.
Voltage output from the 5725A is available at the 5700A Calibrator front or rear binding
posts. This eliminates the need to move cables during a procedure that requires amplified
as well as standard calibrator outputs.
The 5725A front or rear panel OUTPUT binding posts are only for current output.
Extended-range ac and dc current is supplied through them. Since most meters with a
high current range use a separate high current input terminal, this configuration normally
eliminates the need to move cables during a procedure. If a single-point current output is
needed, the 5700A Calibrator can be configured to source all current outputs through the
5725A binding posts.
Enhancements to 5700A ac voltage output capability provided by the 5725A are as
follows:
• Frequency limits at higher voltage increase to 100 kHz at 750V, 30 kHz at 1100V.
• Load limits are to 70 mA for frequencies above 5 kHz, and to 50 mA for frequencies
less than 5 kHz.
• Capacitive load limits are increased to 1000 pF.
Model 5725A operating functions and ranges are as follows:
• AC voltage: 220 to 1100V rms up to 70 mA (50 mA < 5 kHz), 40 Hz to 30 kHz; 220
to 750V rms up to 70 mA, 30 kHz to 100 kHz
• DC current: 0 to ±11A
• AC current: 1 to 11A rms, 40 Hz to 10 kHz
To contact Fluke, call one of the following telephone numbers:
USA: 1-888-99-FLUKE (1-888-993-5853)
Canada: 1-800-36-FLUKE (1-800-363-5853)
Europe: +31 402-678-200
Japan: +81-3-3434-0181
Singapore: +65-738-5655
Anywhere in the world +1-425-446-5500
Or, visit Fluke’s web site at www.fluke.com.
1-3
5725A
r
t
t
Instruction Manual
1-2. Where to Go From Here
This manual is the operator and service manual for the 5725A. However, because the
5725A operates under the control of the 5700A Calibrator, most operating instructions
for the 5725A are in the 5700A/5720A Series II manuals. Topics such as selecting output
values, connecting to a UUT (Unit Under Test), and self calibration are covered in the
5700A/5720A Series II Operator Manual. The list below gives some specific pointers,
and the text further on describes how to use all the manuals to find 5725A information.
For More Information About: Refer To:
• Unpacking and setup Section 2 of this manual
• Installation and rack mounting Section 2 of this manual and the
Y5735/Y5737 Instruction Sheet
• AC line power and interface cabling Section 2 of this manual
• Controls, indicators, and binding
Section 3 of this manual
posts
• 5725A service information Sections 4 through 9 of this manual
• Operating the amplifie
Section 3 of this manual and Section 4 of
the 5700A/5720A Series II Operator
Manual
• Cabling to a Unit Under Tes
Section 4 of the 5700A/5720A Series II
Operator Manual
• Self calibration Section 7 of the 5700A/5720A Series II
Operator Manual
• Full verification Section 3 of the 5700A/5720A Series II
Service Manual
• IEEE-488 or serial remote operation Section 5 of the 5700A/5720A Series II
Operator Manual
• 5700A/5725A specifications Section 1 of this manual
• Theory of operation Section 4 and 9 of this manual
• Troubleshooting Section 6 of this manual
• Ordering a par
Section 8 of this manual
1-4
Introduction and Specifications
How to Use the Manuals 1
1-3. How to Use the Manuals
The following paragraphs describe how each manual addresses the 5725A.
1-4. 5725A Getting Started Manual
Use this manual for basic getting started information, contacting Fluke, unpacking, and
general specifications. This manual also provides setup and operation information for the
5725A Amplifier, descriptions of the 5725A front and rear-panel features, and
information about setting up and powering up the 5725A. Please read this information
before operating the amplifier.
1-5. 5725A Instruction Manual
Use the 5725A Instruction Manual for installing the 5725A, learning about its front and
rear-panel features, and for all service-related topics such as maintenance,
troubleshooting, parts lists, and schematics. (The 5725A Instruction Manual is the service
and operator manual for the 5725A.)
Although the instruction manual also contains a section devoted to 5725A operating
notes, once the 5725A is up and running you will find that the 5700A/5720A Operator
Manual contains most of the information you need to operate the 5725A.
1-6. 5700A/5720A Series II Manual Set
The 5700A/5720A Series II Manual Set consists of a Getting Started Manual, an
Operator Reference Guide, a Remote Programming Reference Guide and a CD-ROM
containing an Operators Manual and Service Manual (in addition to all the other manuals
provided in printed form).
1-7. 5700A/5720A Series II Operator Manual
The 5700A/5720A Series II Operator Manual contains the following information
pertaining to the 5725A:
• Specifications for both the 5700A and 5725A (these same specifications are in this
Instruction Manual)
• Cable connections to a UUT for amplified voltage and current
• Front panel (local) operation
• Remote control operation, IEEE-488 or RS-232
• Self calibration
• Fault codes (these appear on the 5700A Control Display, or are read from the 5700A
in remote control operation)
• Calibration constant symbolic names
• Glossary of calibration-related terms
1-8. 5700A/5720A Series II Operator Reference Guide
The 5700A/5720A Series II Operator Reference Guide contains a summary of operating
instructions from the Operator Manual. This booklet contains information needed to start
up and operate the 5700A, but since the 5700A controls the 5725A, much of this
information applies to the 5725A.
1-5
5725A
Instruction Manual
1-9. 5700A/5720A Series II Remote Programming Reference Guide
1-10. 5700A/5720A Series II Service Manual
1-11. Specifications
The 5700A/5720A Series II Remote Programming Reference Guide contains a summary
of remote commands for the 5700A. It also contains information needed to determine
system status using the status byte and registers. Remote commands and system status
apply to a 5725A under control of the 5700A.
The 5700A/5720A Series II Service Manual is a maintenance guide for the 5700A. The
following 5725A topics are included in the 5700A/5720A Series II Service Manual:
• Specifications for both the 5700A and 5725A
• Full verification of the 5700A and 5725A (recommended every two years)
• Calibration of the 5700A and 5725A
Specifications are valid after allowing a warm-up period of 30 minutes, or if the 5725A
has been recently on, twice the time the 5725A has been turned off. For example, if the
5725A has been turned off for five minutes, the warm-up period is ten minutes.
Absolute uncertainty includes stability, temperature coefficient, linearity, line and load
regulation, and traceability to external standards. You do not need to add anything to
absolute uncertainty to determine the ratios between 5700A/5725A uncertainties and the
uncertainties of your calibration workload.
Relative uncertainty specifications are provided for enhanced accuracy applications.
These specifications apply when range constants are adjusted (see "Range Calibration" in
the 5700A/5720A Series II Operator Manual). To calculate absolute uncertainty, you
must combine the uncertainties of your external standards and techniques with relative
uncertainty.
Secondary performance specifications and operating characteristics are included in the
uncertainty specifications. They are also provided separately for special calibration
requirements such as stability or linearity testing.
The specifications for the 5725A are provided in the following tables as subsets to the
5700A and 5720A Series II Calibrators.
1-6
Introduction and Specifications
DC Voltage Specifications 1
1-12. DC Voltage Specifications
Table 1-1. 5720A Series II DC Voltage Specifications: 99 % and 95 % Confidence Levels
5720A
99%
99 % Confidence Level
Absolute Uncertainty
± 5 °C from calibration temperature
Range Resolution
24 Hours 90 Days 180 Days 1 Year 24 Hours 90 Days
± (ppm output + μV) ± (ppm output + μV)
220 mV 10 nV 5 + 0.5 7 + 0.5 8 + 0.5 0 9 + 0.5 2 + 0.4 2.5 + 0.4
2.2 V 100 nV 3.5 + 0.8 4 + 0.8 4.5 + 0.8 0 6 + 0.8 2 + 0.8 2.5 + 0.8
11 V 1 μV 2.5 + 3 3 + 3 3.5 + 3 0 4 + 3 1 + 3 1.5 + 3
22 V 1 μV 2.5 + 5 3 + 5 3.5 + 5 0 4 + 5 1 + 5 1.5 + 5
220 V 10 μV 3.5 + 50 4 + 50 5 + 50 06 + 50 2 + 50 2.5 + 50
1100 V 100 μV 5 + 500 6 + 500 7 + 500 08 + 500 2.5 + 400 3 + 400
For fields strengths >1 V/m but ≤3 V/m,
add 0.01% of range.
Relative Uncertainty
± 1 °C
5720A
95%
95% Confidence Level
Absolute Uncertainty
± 5 °C from calibration temperature
Range Resolution
24 Hours 90 Days 180 Days 1 Year 24 Hours 90 Days
± (ppm output + μV) ± (ppm output + μV)
For fields strengths >1 V/m but ≤3 V/m,
add 0.01 % of range.
Relative Uncertainty
± 1 °C
220 mV 10 nV 4 + 0.4 6 + 0.4 6.5 + 0.4 7.5 + 0.4 1.6 + 0.4 2 + 0.4
2.2 V 100 nV 3 + 0.7 3.5 + 0.7 4 + 0.7 5 + 0.7 1.6 + 0.7 2 + 0.7
11 V 1 μV 2 + 2.5 2.5 + 2.5 3 + 2.5 3.5 + 2.5 0.8 + 2.5 1.2 + 2.5
22 V 1 μV 2 + 4 2.5 + 4 3 + 4 3.5 + 4 0.8 + 4 1.2 + 4
220 V 10 μV 3 + 40 3.5 + 40 4 + 40 5 + 40 1.6 + 40 2 + 40
1100 V 100 μV 4 + 400 4.5 + 400 6 + 400 6.5 + 400 2 + 400 2.4 + 400
1-7
5725A
Instruction Manual
5700A
99%
Table 1-2. 5700A Series II DC Voltage Specifications: 99 % and 95 % Confidence Levels
99 % Confidence Level
Absolute Uncertainty
± 5 °C from calibration temperature
Range Resolution
24 Hours 90 Days 180 Days 1 Year 24 Hours 90 Days
± (ppm output + μV) ± (ppm output + μV)
220 mV 10 nV 6.5 + .75 7 + .75 8 + .75 9 + .8 2.5 + .5 4 + .5
2.2 V 100 nV 3.5 + 1.2 6 + 1.2 7 + 1.2 8 + 1.2 2.5 + 1.2 4 + 1.2
11 V 1 μV 3.5 + 3 5 + 4 7 + 4 8 + 4 1.5 + 3 3.5 + 4
22 V 1 μV 3.5 + 6 5 + 8 7 + 8 8 + 8 1.5 + 6 3.5 + 8
220 V 10 μV 5 + 100 6 + 100 8 + 100 9 + 100 2.5 + 100 4 + 100
1100 V 100 μV 7 + 600 8 + 600 10 + 600 11 + 600 3 + 600 4.5 + 600
For fields strengths >1 V/m but ≤3 V/m,
add 0.01 % of range.
Relative Uncertainty
± 1 °C
5700A
95%
95 % Confidence Level
Absolute Uncertainty
± 5 °C from calibration temperature
Range Resolution
24 Hours 90 Days 180 Days 1 Year 24 Hours 90 Days
± (ppm output + μV) ± (ppm output + μV)
For fields strengths >1 V/m but ≤3 V/m,
add 0.01 % of range.
Relative Uncertainty
± 1 °C
1-8
220 mV 10 nV 5.5 + 0.6 6 + 0.6 7 + 0.6 8 + 0.6 2 + 0.4 3.5 + 0.4
2.2 V 100 nV 3.5 + 1 5 + 1 6 + 1 7 + 1 2 + 1 3.5 + 1
11 V 1 mV 3 + 3.5 4 + 3.5 6 + 3.5 7 + 3.5 1.2 + 3 3 + 3.5
22 V 1 mV 3 + 6.5 4 + 6.5 6 + 6.5 7 + 6.5 1.2 + 6 3 + 7
220 V 10 mV 4 + 80 5 + 80 7 + 80 8 + 80 2 + 80 3.5 + 80
1100 V 100 mV 6 + 500 7 + 500 8 + 500 9 + 500 2.4 + 500 4 + 500
Introduction and Specifications
Table 1-3. DC Voltage Secondary Performance Specifications and Operating Characteristics
DC Voltage Specifications 1
Temperature Coefficient
Adder [Note 2]
Range Stability [Note 1]
± 1 °C
24 Hours 40°-50 °C pk-pk RMS
± (ppm output + μV) ± (ppm output + μV)/°C ± (ppm output + μV) μV
220 mV
2.2 V
11 V
22 V
220 V
1100 V
0.3 + 0.3
0.3 + 1
0.3 + 2.5
0.4 + 5
0.5 + 40
0.5 + 200
10 °-40 °C 0 °-10 °C
and
0.4 + 0.1
0.3 + 0.1
0.15 + 0.2
0.2 + 0.4
0.3 + 5
0.5 + 10
1.5 + 0.5
1.5 + 2
1 + 1.5
1.5 + 3
1.5 + 40
3 + 200
Noise
Linearity
± 1 °C
1 + 0.2
1 + 0.6
0.3 + 2
0.3 + 4
1 + 40
1 + 200
Bandwidth
0.1-10 Hz
0.15 + 0.1
0.15 + 0.4
0.15 + 2
0.15 + 4
0.15 + 60
0.15 + 300
Bandwidth
10 Hz-10 kHz
5
15
50
50
150
500
Notes:
1. Stability specifications are included in the Absolute Uncertainty values in the primary specification
tables.
2. Temperature coefficient is an adder to uncertainty specifications that does not apply unless operating
more than ±5 °C from calibration temperature.
Minimum output: 0 V for all ranges, except 100 V for 1100 V range
Maximum load: 50 mA for 2.2 V through 220 V ranges; 20 mA for 1100 V range; 50 Ω output impedance on
220 mV range; all ranges <1000 pF, >25 Ω
Load regulation: <(0.2 ppm of output + 0.1ppm of range), full load to no load
Line regulation: <0.1 ppm change, ± 10 % of selected nominal line
Settling time: 3 seconds to full accuracy; + 1 second for range or polarity change; + 1 second for 1100 V
range
Overshoot: <5 %
Common mode rejection: 140 dB, DC to 400 Hz
Remote sensing: Available 0 V to ±1100 V, on 2.2 V through 1100 V ranges
1-9
5725A
Instruction Manual
1-13. AC Voltage Specifications
Table 1-4. 5720A Series II AC Voltage Specifications: 99 % Confidence Level
5720A
99%
99 % Confidence Level
Range Resolution Frequency
24 Hours 90 Days 180 Days 1 Year 24 Hours 90 Days
Hz ± (ppm output + μV) ± (ppm output + μV)
2.2 mV
22 mV 10 nV
220 mV 100 nV
2.2 V 1 mV
22 V 10 mV
1 nV
0010 - 20
0020 - 40
0040 - 20 k
020 k - 50 k
050 k - 100 k
100 k - 300 k
300 k - 500 k
500 k - 1 M
0010 - 20
0020 - 40
0040 - 20 k
020 k - 50 k
050 k - 100 k
100 k - 300 k
300 k - 500 k
500 k - 1 M
0010 - 20
0020 - 40
0040 - 20 k
020 k - 50 k
050 k - 100 k
100 k - 300 k
300 k - 500 k
500 k - 1 M
0010 - 20
0020 - 40
0040 - 20 k
020 k - 50 k
050 k - 100 k
100 k - 300 k
300 k - 500 k
500 k - 1 M
0010 - 20
0020 - 40
0040 - 20 k
020 k - 50 k
050 k - 100 k
100 k - 300 k
300 k - 500 k
500 k - 1 M
0250 + 5
0100 + 5
0085 + 5
0220 + 5
0500 + 6
1000 + 12
1400 + 25
2900 + 25
0250 + 5
0100 + 5
0085 + 5
0220 + 5
0500 + 6
1000 + 12
1400 + 25
2900 + 25
0250 + 15
0100 + 8
0085 + 8
0220 + 8
0500 + 20
0850 + 25
1400 + 30
2700 + 60
0250 + 50
0095 + 20
0045 + 10
0080 + 12
0120 + 40
0380 + 100
1000 + 250
1600 + 400
0250 + 500
0095 + 200
0045 + 70
0080 + 120
0110 + 250
0300 + 800
1000 + 2500
1500 + 4000
± (ppm output + mV) ± (ppm output + mV)
220 V
[Note 2]
1100 V
100 mV
1 mV
[Note 1]
0010 - 20
0020 - 40
0040 - 20 k
020 k - 50 k
050 k - 100 k
100 k - 300 k
300 k - 500 k
500 k - 1 M
0015 - 50
0050 - 1 k
0250 + 5
0095 + 2
0057 + 0.7
0090 + 1.2
0160 + 3
0900 + 20
5000 + 50
8000 + 100
0300 + 20
0070 + 4
5725A Amplifier:
0040 - 1 k
1100 V
750 V
Notes: 1. Maximum output 250V from 15-50 Hz.
1 mV
2. See Volt-Hertz capability in Figure 1-2.
001 k - 20 k
020 k - 30 k
030 k - 50 k
050 k - 100k
0075 + 4
0105 + 6
0230 + 11
0230 + 11
0600 + 45
Absolute Uncertainty
± 5 °C from calibration temperature
0270 + 5
0105 + 5
0090 + 5
0230 + 5
0540 + 6
1200 + 12
1500 + 25
3100 + 25
0270 + 5
0105 + 5
0090 + 5
0230 + 5
0540 + 6
1200 + 12
1500 + 25
3100 + 25
0270 + 15
0105 + 8
0090 + 8
0230 + 8
0540 + 20
0900 + 25
1500 + 30
2900 + 60
0270 + 50
0100 + 20
0047 + 10
0085 + 12
0125 + 40
0420 + 100
1100 + 250
1800 + 600
0270 + 500
0100 + 200
0047 + 70
0085 + 120
0115 + 250
0310 + 800
1100 + 2500
1600 + 4000
0270 + 5
0100 + 2
0060 + 0.7
0095 + 1.2
0170 + 3
1000 + 20
5200 + 50
9000 + 100
0320 + 20
0075 + 4
0080 + 4
0125 + 6
0360 + 11
0360 + 11
1300 + 45
0290 + 5
0110 + 5
0095 + 5
0240 + 5
0570 + 6
1250 + 12
1600 + 25
3250 + 25
0290 + 5
0110 + 5
0095 + 5
0240 + 5
0570 + 6
1250 + 12
1600 + 25
3250 + 25
0290 + 15
0110 + 8
0095 + 8
0240 + 8
0570 + 20
1000 + 25
1600 + 30
3100 + 60
0290 + 50
0105 + 20
0050 + 10
0087 + 12
0127 + 40
0460 + 100
1150 + 250
1900 + 400
0290 + 500
0105 + 200
0050 + 70
0087 + 120
0117 + 250
0320 + 800
1150 + 2500
1700 + 4000
0290 + 5
0105 + 2
0062 + 0.7
0097 + 1.2
0175 + 3
1050 + 20
5300 + 50
9500 + 100
0340 + 20
0080 + 4
0085 + 4
0135 + 6
0440 + 11
0440 + 11
1600 + 45
00300 + 5
00115 + 5
00100 + 5
00250 + 5
00600 + 6
01300 + 12
01700 + 25
03400 + 25
00300 + 5
00115 + 5
00100 + 5
00250 + 5
00600 + 6
01300 + 12
01700 + 25
03400 + 25
00300 + 15
00115 + 8
00100 + 8
00250 + 8
00600 + 20
01100 + 25
01700 + 30
03300 + 60
00300 + 50
00110 + 20
00052 + 10
00090 + 12
00130 + 40
00500 + 100
01200 + 250
02000 + 400
00300 + 500
00110 + 200
00052 + 70
00090 + 120
00120 + 250
00325 + 800
01200 + 2500
01800 + 4000
00300 + 5
00110 + 2
00065 + 0.7
00100 + 1.2
00 180 + 3
0 1100 + 20
0 5400 + 50
10,000 + 100
00 360 + 20
00085 + 4
000 90 + 4
00 165 + 6
00 600 + 11
00600 + 11
02300 + 45
Relative Uncertainty
± 1 °C
0250 + 5
0100 + 5
0060 + 5
0085 + 5
0200 + 6
0350 + 12
0800 + 25
2700 + 25
0250 + 5
0100 + 5
0060 + 5
0085 + 5
0200 + 6
0350 + 12
0800 + 25
2700 + 25
0250 + 15
0100 + 8
0060 + 8
0085 + 8
0200 + 20
0350 + 25
0800 + 30
2600 + 60
0250 + 50
0095 + 20
0030 + 10
0070 + 12
0100 + 40
0270 + 100
0900 + 250
1200 + 400
0250 + 500
0095 + 200
0030 + 70
0070 + 120
0100 + 250
0270 + 800
0900 + 2500
1300 + 4000
0250 + 5
0095 + 2
0045 + 0.7
0075 + 1.2
0140 + 3
0600 + 20
4500 + 50
8000 + 100
0300 + 20
0050 + 4
0050 + 4
0085 + 6
0160 + 11
0160 + 11
0380 + 45
0270 + 5
0105 + 5
0065 + 5
0095 + 5
0220 + 6
0400 + 12
1000 + 25
3000 + 25
0270 + 5
0105 + 5
0065 + 5
0095 + 5
0220 + 6
0400 + 12
1000 + 25
3000 + 25
0270 + 15
0105 + 8
0065 + 8
0095 + 8
0220 + 20
0400 + 25
1000 + 30
2800 + 60
0270 + 50
0100 + 20
0040 + 10
0075 + 12
0105 + 40
0290 + 100
1000 + 250
1300 + 400
0270 + 500
0100 + 200
0040 + 70
0075 + 120
0105 + 250
0290 + 800
1000 + 2500
1400 + 4000
0270 + 5
0100 + 2
0050 + 0.7
0080 + 1.2
0150 + 3
0700 + 20
4700 + 50
8500 + 100
0320 + 20
0055 + 4
0055 + 4
0105 + 6
0320 + 11
0320 + 11
1200 + 45
1-10
Introduction and Specifications
Table 1-5. 5720A Series II AC Voltage Specifications: 95 % Confidence Level
5720A
95%
95 % Confidence Level
Range Resolution Frequency
24 Hours 90 Days 180 Days 1 Year 24 Hours 90 Days
Hz ± (ppm output + μV) ± (ppm output + μV)
0200 + 4
0080 + 4
0070 + 4
0170 + 4
0400 + 5
0300 + 10
1100 + 20
2400 + 20
0200 + 4
0080 + 4
0070 + 4
0170 + 4
0400 + 5
0300 + 10
1100 + 20
2400 + 20
0200 + 12
0080 + 7
0070 + 7
0170 + 7
0400 + 17
0700 + 20
1100 + 25
2400 + 45
0200 + 40
0075 + 15
0037 + 8
0065 + 10
0100 + 30
0300 + 80
0800 + 200
1300 + 300
0200 + 400
0075 + 150
0037 + 50
0065 + 100
0090 + 200
0250 + 600
0800 + 2000
1200 + 3200
2.2 mV 1 nV
22 mV 10 nV
220 mV 100 nV
2.2 V 1 mV
22V 10 mV
0010 - 20
0020 - 40
0040 - 20 k
020 k - 50 k
050 k - 100 k
100 k - 300 k
300 k - 500 k
500 k - 1 M
0010 - 20
0020 - 40
0040 - 20 k
020 k - 50 k
050 k - 100 k
100 k - 300 k
300 k - 500 k
500 k - 1 M
0010 - 20
0020 - 40
0040 - 20 k
020 k - 50 k
050 k - 100 k
100 k - 300 k
300 k - 500 k
500 k - 1 M
00010 - 20
0020 - 40
0040 - 20 k
020 k - 50 k
050 k - 100 k
100 k - 300 k
300 k - 500 k
500 k - 1 M
0010 - 20
0020 - 40
0040 - 20k
020k - 50k
050k - 100k
100k - 300k
300k - 500k
500k - 1M
± (ppm output + mV) ± (ppm output + mV)
220 V
[Note 2]
1100 V
100 mV
1 mV
[Note 1]
0010 - 20
0020 - 40
0040 - 20 k
020 k - 50 k
050 k - 100 k
100 k - 300 k
300 k - 500 k
500 k - 1 M
0015 - 50
0050 - 1 k
0200 +4
0075 + 1.5
0045 + 0.6
0070 + 1
0120 + 2.5
0700 + 16
4000 + 40
6000 + 80
0240 + 16
0055 + 3.5
5725A Amplifier:
1100 V
1 mV
750 V
Notes: 1. Maximum output 250V from 15-50 Hz.
2. See Volt-Hertz capability in Figure 1-2.
0040 - 1 k
001 k - 20 k
020 k - 30 k
030 k - 50 k
050 k - 100 k
0075 + 4
0105 + 6
0230 + 11
0230 + 11
0600 + 45
Absolute Uncertainty
± 5 °C from calibration temperature
0220 + 4
0085 + 4
0075 + 4
0180 + 4
0460 + 5
0900 + 10
1200 + 20
2500 + 20
0220 + 4
0085 + 4
0075 + 4
0180 + 4
0460 + 5
0900 + 10
1200 + 20
2500 + 20
0220 + 12
0085 + 7
0075 + 7
0180 + 7
0420 + 17
0750 + 20
1200 +25
2500 + 45
0220 + 40
0080 + 15
0040 + 8
0070 + 10
0105 + 30
0340 + 80
0900 + 200
1500 + 300
0220 + 400
0080 + 150
0040 + 50
0070 + 100
0095 + 200
0260 + 600
0900 + 2000
1300 + 3200
0220 + 4
0080 + 1.5
0047 + 0.6
0075 + 1
0130 + 2.5
0800 + 16
4200 + 40
7000 + 80
0260 + 16
0060 + 3.5
0080 + 4
0125 + 6
0360 + 11
0360 + 11
1300 + 45
0230 + 4
0087 + 4
0077 + 4
0190 + 4
0480 + 5
1000 + 10
1300 + 20
2600 + 20
0230 + 4
0087 + 4
0077 + 4
0190 + 4
0480 + 5
1000 + 10
1300 + 20
2600 + 20
0230 + 12
0087 + 7
0077 + 7
0190 + 7
0440 + 17
0800 + 20
1300 + 25
2600 + 45
0230 + 40
0085 + 15
0042 + 8
0073 + 10
0107 + 30
0380 + 80
0950 + 200
1600 + 300
0230 + 400
0085 + 150
0042 + 50
0073 + 100
0097 + 200
0270 + 600
0900 + 2000
1400 + 3200
0230 + 4
0085 + 1.5
0050 + 0.6
0077 + 1
0140 + 2.5
0850 + 16
4300 + 40
7500 + 80
0280 + 16
0065 + 3.5
0085 + 4
0135 + 6
0440 + 11
0440 + 11
1600 + 45
0240 + 4
0090 + 4
0080 + 4
0200 + 4
0500 + 5
1050 + 10
1400 + 20
2700 + 20
0240 + 4
0090 + 4
0080 + 4
0200 + 4
0500 + 5
1050 + 10
1400 + 20
2700 + 20
0240 + 12
0090 + 7
0080 + 7
0200 + 7
0460 + 17
0900 + 20
1400 + 25
2700 + 45
0240 + 40
0090 + 15
0045 + 8
0075 + 10
0110 + 30
0420 + 80
1000 + 200
1700 + 300
0240 + 400
0090 + 150
0045 + 50
0075 + 100
0100 + 200
0275 + 600
1000 + 2000
1500 + 3200
0240 + 4
0090 + 1.5
0052 + 0.6
0080 + 1
0150 + 2.5
0900 + 16
4400 + 40
8000 + 80
0300 + 16
0070 + 3.5
0090 + 4
0165 + 6
0600 + 11
0600 + 11
2300 + 45
AC Voltage Specifications 1
Relative Uncertainty
± 1 °C
0200 + 4
0080 + 4
0050 + 4
0070 + 4
0160 + 5
0280 + 10
0650 + 20
2100 + 20
0200 + 4
0080 + 4
0050 + 4
0070 + 4
0160 + 5
0280 + 10
0650 + 20
2100 + 20
0200 + 12
0080 + 7
0050 + 7
0070 + 7
0160 + 17
0280 + 20
0650 + 25
2100 + 45
0200 + 40
0075 + 15
0025 + 8
0055 + 10
0080 + 30
0230 + 80
0700 + 200
1000 + 300
0200 + 400
0075 + 150
0025 + 50
0055 + 100
0080 + 200
0250 + 600
0700 + 2000
1100 + 3200
0200 + 4
0075 + 1.5
0035 + 0.6
0060 + 1
0110 + 2.5
0500 + 16
3600 + 40
6500 + 80
0240 + 16
0040 + 3.5
0050 + 4
0085 + 6
0160 + 11
0160 + 11
0380 + 45
0220 + 4
0085 + 4
0055 + 4
0080 + 4
0180 + 5
0320 + 10
0800 + 20
2400 + 20
0220 + 4
0085 + 4
0055 + 4
0080 + 4
0180 + 5
0320 + 10
0800 + 20
2400 + 20
0220 + 12
0085 + 7
0055 + 7
0080 + 7
0180 + 17
0320 + 20
0800 + 25
2400 + 45
0220 + 40
0080 + 15
0035 + 8
0060 + 10
0085 + 30
0250 + 80
0800 + 200
1100 + 300
0220 + 400
0080 + 150
0035 + 50
0060 + 100
0085 + 200
0270 + 600
0800 + 2000
1200 + 3200
0220 + 4
0080 + 1.5
0040 + 0.6
0065 + 1
0120 + 2.5
0600 + 16
3800 + 40
7000 + 80
0260 + 16
0045 + 3.5
0055 + 4
0105 + 6
0320 + 11
0320 + 11
1200 + 45
1-11
5725A
μ
V
μ
V
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
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0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
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0
0
Instruction Manual
Table 1-6. 5700A Series II AC Voltage Specifications: 99 % Confidence Level
5700A
99%
99 % Confidence Level
Range Resolution Frequency
24 Hours 90 Days 180 Days 1 Year 24 Hours 90 Days
Hz ± (ppm output +
2.2 mV
22 mV 10 nV
220 mV 100 nV
2.2 V 1 mV
22 V 10 mV
1 nV
0010 - 20
0020 - 40
0040 - 20 k
020 k - 50 k
050 k - 100 k
100 k - 300 k
300 k - 500 k
500 k - 1 M
0010 - 20
0020 - 40
0040 - 20 k
020 k - 50 k
050 k - 100 k
100 k - 300 k
300 k - 500 k
500 k - 1 M
0010 - 20
0020 - 40
0040 - 20 k
020 k - 50 k
050 k - 100 k
100 k - 300 k
300 k - 500 k
500 k - 1 M
0010 - 20
0020 - 40
0040 - 20 k
020 k - 50 k
050 k - 100 k
100 k - 300 k
300 k - 500 k
500 k - 1 M
0010 - 20
0020 - 40
0040 - 20 k
020 k - 50 k
050 k - 100 k
100 k - 300 k
300 k - 500 k
500 k - 1 M
0 500 + 5
00200 + 5
0 100 + 5
0 340 + 5
0 800 + 8
01100 + 15
01500 + 30
4000 + 40
0 500 + 6
0 200 + 6
0100 + 6
0340 + 6
0800 + 8
1100 + 15
01500 + 30
04000 + 40
0500 + 16
0 200 + 10
0 095 + 10
0 300 + 10
0 750 + 30
0 940 + 30
1500 + 40
3000 + 100
0 500 + 100
0 150 + 30
00 70 + 7
0 120 + 20
0 230 + 80
0 400 + 150
1000 + 400
2000 + 1000
0 500 + 1000
0 150 + 300
00 70 + 70
0 120 + 200
0 230 + 400
0 500 + 1700
1200 + 5000
2600 + 9000
± (ppm output + mV) ± (ppm output + mV)
220 V
[Note 2]
1100 V 1 mV
100 mV
[Note 1]
0010 - 20
0020 - 40
0040 - 20 k
020 k - 50 k
050 k - 100 k
100 k - 300 k
300 k - 500 k
500 k - 1 M
00015 - 50
00050 - 1 k
0 500 + 10
0 150 + 3
00 75 + 1
0 200 + 4
0 500 + 10
1500 + 110
5000 + 110
12,000 + 220
0 400 + 20
00 75 + 4
5725A Amplifier:
1100 V 1 mV 00040 - 1 k
750 V 0030 k - 50 k
Notes: 1. Maximum output 250V from 15-50 Hz.
2. See Volt-Hertz capability in Figure 1-2.
0001 k - 20 k
0020 k - 30 k
0050 k - 100 k
00 75 + 4
0 105 + 6
0 230 + 11
0 230 + 11
0 600 + 45
Absolute Uncertainty
± 5 °C from calibration temperature
) ± (ppm output +
0 550 + 5
0 220 + 5
0 110 + 5
0 370 + 5
0 900 + 8
01200 + 15
01700 + 30
04400 + 40
0 550 + 6
0 220 + 6
0 110 + 6
0 370 + 6
0 900 + 8
01200 + 15
01700 + 30
04400 + 40
0 550 + 16
0 220 + 10
0 100 + 10
0 330 + 10
0 800 + 30
1000 + 30
01700 + 40
03300 + 100
0 550 + 100
0 170 + 30
00 75 + 7
0 130 + 20
0 250 + 80
0 440 + 150
1100 + 400
2200 + 1000
0 550 + 1000
0 170 + 300
00 75 + 70
0 130 + 200
0 250 + 400
0 550 + 1700
1300 + 5000
2800 + 9000
0 550 + 10
0 170 + 3
00 80 + 1
0 220 + 4
0 550 + 10
1500 + 110
5200 + 110
12,500 + 220
00420 + 20
00 80 + 4
00 80 + 4
0 125 + 6
0 360 + 11
0 360 + 11
1300 + 45
0 600 + 5
0 230 + 5
0 120 + 5
0 390 + 5
0 950 + 8
1300 + 15
01700 + 30
4700 + 40
00600 + 6
0 230 + 6
0 120 + 6
0 390 + 6
0 950 + 8
1300 + 15
1700 + 30
4700 + 40
0 600 + 16
0 230 + 10
0 110 + 10
0 350 + 10
0 850 + 30
01100 + 30
1700 + 40
3500 + 100
0 600 + 100
0 170 + 30
00 80 + 7
0 140 + 20
0 270 + 80
0 470 + 150
1200 + 400
2300 + 1000
0 600 + 1000
0 170 + 300
00 80 + 70
0 140 + 200
0 270 + 400
0 550 + 1700
1300 + 5000
2900 + 9000
0600 + 10
0 170 + 3
00 85 + 1
0 240 + 4
0 600 + 10
1600 + 110
5300 + 110
12,500 + 220
00440 + 20
00 85 + 4
00 85 + 4
0 135 + 6
0 440 + 11
0 440 + 11
1600 + 45
0 600 + 5
0 240 + 5
0 120 + 5
0 410 + 5
0950 + 8
1300 + 15
1800 + 30
4800 + 40
0600 + 6
0 240 + 6
0 120 + 6
0 410 + 6
0 950 + 8
1300 + 15
1800 + 30
4800 + 40
0 600 + 16
00240 + 10
00110 + 10
00360 + 10
0900 + 30
01100 + 30
01800 + 40
03600 + 100
0 600 + 100
0 180 + 30
00 85 + 7
0 140 + 20
0 280 + 80
0 480 + 150
1200 + 400
2400 + 1000
0 600 + 1000
0 180 + 300
00 85 + 70
0 140 + 200
0 280 + 400
0 600 + 1700
1400 + 5000
3000 + 9000
0 600 + 10
0 180 + 3
00 90 + 1
0 250 + 4
0 600 + 10
1600 + 110
5400 + 110
13,000 + 220
00460 + 20
00 90 + 4
00 90 + 4
0 165 + 6
0 600 + 11
0 600 + 11
2300 + 45
Relative Uncertainty
± 1 °C
)
00 500 + 5
00 200 + 5
000 60 + 5
00 100 + 5
00 220 + 8
00 400 + 15
01000 + 30
00 400 + 30
00 500 + 6
00 200 + 6
000 60 + 6
00 100 + 6
00 220 + 8
00 400 + 15
01000 + 30
0 4000 + 30
00 500 + 16
00200 + 10
00060 + 10
00100 + 10
00220 + 30
00400 + 30
01000 + 40
03000 + 100
00 500 + 100
00 150 + 30
000 40 + 7
00 100 + 20
00 200 + 80
00 400 + 150
0 1000 + 400
0 2000 + 1000
00 500 + 1000
00 150 + 300
000 40 + 70
00 100 + 200
00 200 + 400
00500 + 1700
01200 + 5000
02600 + 9000
00 500 + 10
00 150 + 3
000 45 + 1
00 100 + 1
00 300 + 10
01500 + 110
0 5000 + 110
12,000 + 220
00400 + 20
000 50 + 4
000 50 + 4
000 85 + 6
00 160 + 11
00 160 + 11
00 380 + 45
0 550 + 5
0220 + 5
0 065 + 5
0 110 + 5
0 240 + 8
0 440 + 15
1100 + 30
4400 + 30
0 550 + 6
0 220 + 6
00 65 + 6
0 110 + 6
0 240 + 8
0 440 + 15
1100 + 30
4400 + 30
00550 + 16
00220 + 10
00065 + 10
00110 + 10
00240 + 30
00440 + 30
01100 + 40
03300 + 100
0 550 + 100
0 170 + 30
00 45 + 7
0 110 + 20
0 220 + 80
0 440 + 150
1100 + 400
2200 + 1000
0 550 + 1000
0 170 + 300
00 45 + 70
0 110 + 200
0 220 + 400
0 550 + 1700
1300 + 5000
2800 + 9000
0 550 + 10
0 170 + 3
00 50 + 1
0 110 + 1
0 330 + 10
1500 + 100
5200 + 110
12,000 + 220
00420 + 20
00 55 + 4
00 55 + 4
0 105 + 6
0 320 + 11
0 320 + 11
1200 + 45
1-12
Introduction and Specifications
0
0
0
0
0
0
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0
0
0
0
0
0
0
0
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0
0
0
0
0
0
0
0
0
0
0
0
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0
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0
0
0
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0
0
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0
0
0
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0
0
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0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
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0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Table 1-7. 5700A Series II AC Voltage Specifications: 95 % Confidence Level
5700A
95%
95% Confidence Level
Range Resolution Frequency
24 Hours 90 Days 180 Days 1 Year 24 Hours 90 Days
Hz ± (ppm output + μV) ± (ppm output + μV)
2.2 mV
22 mV 10 nV
220 mV 100 nV
2.2 V 1 mV
22 V 10 mV
1 nV
0010 - 20
0020 - 40
0040 - 20 k
020 k - 50 k
050 k - 100 k
100 k - 300 k
300 k - 500 k
500 k - 1 M
0010 - 20
0020 - 40
0040 - 20 k
020 k - 50 k
050 k - 100 k
100 k - 300 k
300 k - 500 k
500 k - 1 M
0010 - 20
0020 - 40
0040 - 20 k
020 k - 50 k
050 k - 100 k
100 k - 300 k
300 k - 500 k
500 k - 1 M
0010 - 20
0020 - 40
0040 - 20 k
020 k - 50 k
050 k - 100 k
100 k - 300 k
300 k - 500 k
500 k - 1 M
0010 - 20
0020 - 40
0040 - 20 k
020 k - 50 k
050 k - 100 k
100 k - 300 k
300 k - 500 k
500 k - 1 M
0 400 + 4.5
0 170 + 4.5
00 85 + 4.5
0 300 + 4.5
0 700 + 7
0 900 + 13
1300 + 25
2800 + 25
0 400 + 5
0 170 + 5
00 85 + 5
0 300 + 5
0 700 + 7
0 900 + 12
1300 + 25
2800 + 25
0 400 + 13
0 170 + 8
00 85 + 8
0 250 + 8
0 700 + 25
0 900 + 25
1300 + 35
2800 + 80
0 400 + 80
0 130 + 25
00 60 + 6
0 105 + 16
0 190 + 70
0 350 + 130
0 850 + 350
1700 + 850
0 400 + 800
0 130 + 250
00 60 + 60
0 105 + 160
0 190 + 350
0 400 + 1500
1050 + 4300
2300 + 8500
± (ppm output + mV)
0 400 + 8
0 130 + 2.5
00 65 + 0.8
0 170 + 3.5
0 400 + 8
1300 + 90
4300 + 90
10,500 + 190
0 340 + 16
00 65 + 3.5
220 V
[Note 2]
1100 V
100 mV
1 mV
[Note 1]
0010 - 20
0020 - 40
0040 - 20 k
020 k - 50 k
050 k - 100 k
100 k - 300 k
300 k - 500 k
500 k - 1 M
0015 - 50
0050 - 1 k
5725A Amplifier:
1100 V
750 V
Notes: 1. Maximum output 250V from 15-50 Hz.
2. See Volt-Hertz capability in Figure 1-2.
1 mV
030 k - 50 k
0040 - 1 k
001 k - 20 k
020 k - 30 k
050 k - 100 k
00 75 + 4
0 105 + 6
0 230 + 11
0 230 + 11
0 600 + 45
Absolute Uncertainty
± 5 °C from calibration temperature
0 500 + 4.5
0 190 + 4.5
00 95 + 4.5
0 330 + 4.5
0750 + 7
1000 + 13
1500 + 25
3100 + 25
0 500 + 5
0 190 + 5
00 95 + 5
0 330 + 5
0 750 + 7
1000 + 12
1500 + 25
3100 + 25
0 500 + 13
0 190 + 8
00 95 + 8
0 280 + 8
0 750 + 25
1000 + 25
1500 + 35
3100 + 80
0 450 + 80
0 140 + 25
00 65 + 6
0 110 + 16
0 210 + 70
0 390 + 130
0950 + 350
1900 + 850
0 450 + 800
0 140 + 250
00 65 + 60
0 110 + 160
0 210 + 350
0 450 + 1500
1150 + 4300
2500 + 8500
0 450 + 8
0 140 + 2.5
00 70 + 0.8
0 190 + 3.5
0 450 + 8
1400 + 90
4500 + 90
11,000 + 190
00360 + 16
00 70 + 3.5
00 80 + 4
0 125 + 6
0 360 + 11
0 360 + 11
1300 + 45
0 530 + 4.5
0 200 + 4.5
0 100 + 4.5
0 350 + 4.5
0 800 + 7
1050 + 13
1600 + 25
3300 + 25
0 530 + 5
0 200 + 5
0 100 + 5
0 350 + 5
0 800 + 7
1050 + 12
1600 + 25
3300 + 25
0 530 + 13
0 200 + 8
0 100 + 8
0 300 + 8
0 800 + 25
1050 + 25
1600 + 35
3300 + 80
0 480 + 80
0 150 + 25
00 70 + 6
0 115 + 16
0 230 + 70
0 420 + 130
1000 + 350
2100 + 850
0 480 + 800
0 150 + 250
00 70 + 60
0 115 + 160
0 230 + 350
0 470 + 1500
1200 + 4300
2600 + 8500
0 480 + 8
0 150 + 2.5
00 75 + 0.8
0 210 + 3.5
0 480 + 8
1450 + 90
4600 + 90
11,300 + 190
00380 + 16
00 75 + 3.5
00 85 + 4
0 135 + 6
0 440 + 11
0 440 + 11
1600 + 45
0 550 + 4.5
0 210 + 4.5
0 105 + 4.5
0 370 + 4.5
0 850 + 7
1100 + 13
1700 + 25
3400 + 25
0 550 + 5
0 210 + 5
0 105 + 5
0 370 + 5
0 850 + 7
1100 + 12
1700 + 25
3400 + 25
0 550 + 13
0 210 + 8
0 105 + 8
0 320 + 8
0 850 + 25
1100 + 25
1700 + 35
3400 + 80
0 500 + 80
0 160 + 25
00 75 + 6
0 120 + 16
0 250 + 70
0 430 + 130
1050 + 350
2200 + 850
0 500 + 800
0 160 + 250
00 75 + 60
0 120 + 160
0 250 + 350
0 500 + 1500
1250 + 4300
2700 + 8500
0 500 + 8
0 160 + 2.5
00 80 + 0.8
0 220 + 3.5
0 500 + 8
1500 + 90
4700 + 90
11,500 + 190
00400 + 16
00 80 + 3.5
00 90 + 4
0 165 + 6
0 600 + 11
0 600 + 11
2300 + 45
AC Voltage Specifications 1
Relative Uncertainty
± 1 °C
00 400 + 4.5
00 170 + 4.5
000 55 + 4.5
000 90 + 4.5
00 210 + 7
00 380 + 13
00 900 + 25
0 2900 + 25
00 400 + 5
00 170 + 5
000 55 + 5
000 90 + 5
00 210 + 7
00 380 + 12
00900 + 25
0 2900 + 25
00 400 + 13
00 170 + 8
000 55 + 8
000 90 + 8
00 210 + 25
00 380 + 25
00 900 + 35
0 2900 + 80
00 400 + 80
00 130 + 25
000 35 + 6
000 85 + 16
00 170 + 70
00 340 + 130
00 850 + 350
0 1700 + 850
00 400 + 800
00 130 + 250
000 35 + 60
000 85 + 160
00 170 + 350
00 400 + 1500
0 1000 + 4300
0 2200 + 8500
± (ppm output + mV)
00 400 + 8
00 130 + 2.5
000 40 + 0.8
000 85 + 3.5
00 270 + 8
0 1200 + 90
0 4200 + 90
10,500 + 190
00340 + 16
000 45 + 3.5
000 50 + 4
000 85 + 6
00 160 + 11
00 160 + 11
00 380 + 45
0 500 + 4.5
0 190 + 4.5
00 60 + 4.5
0 100 + 4.5
0 230 + 7
0 420 + 13
1000 + 25
3200 + 25
0 500 + 5
0 190 + 5
00 60 + 5
0 100 + 5
0 230 + 7
0 420 + 12
1000 + 25
3200 + 25
0 500 + 13
0 190 + 8
00 60 + 8
0 100 + 8
0 230 + 25
0 420 + 25
1000 + 35
3200 + 80
0 450 + 80
0 140 + 25
00 40 + 6
00 95 + 16
0 190 + 70
0 380 + 130
0 950 + 350
1900 + 850
0 450 + 800
0 140 + 250
00 40 + 60
00 95 + 160
0 190 + 350
0 450 + 1500
1100 + 4300
2400 + 8500
0 450 + 8
0 140 + 2.5
00 45 + 0.8
00 95 + 3.5
0 300 + 8
1300 + 90
4500 + 90
11,000 + 190
00360 + 16
00 50 + 3.5
00 55 + 4
0 105 + 6
0 320 + 11
0 320 + 11
1200 + 45
1-13
5725A
Instruction Manual
Stability
Range Frequency 24 Hours 10°-40 °C 0°-10 °C and
Hz ± μV ±μV/°C Ω ± (% output + μV)
2.2 mV
22 mV
220 mV
Load Regulation
2.2 V
22 V
220 V
1100 V
Note: 1. Stability specifications are included in Absolute Uncertainty values for the primary specifications.
Table 1-8. AC Voltage Secondary Performance Specifications and Operating Characteristics
Temperature Coefficient Maximum
± 1 °C [Note 1]
Output Impedance Bandwidth
40°-50 °C
0010 - 20
0020 - 40
0040 - 20 k
020 k - 50 k
050 k - 100 k
100 k - 300 k
300 k - 500 k
500 k - 1 M
0010 - 20
0020 - 40
0040 - 20 k
020 k - 50 k
050 k - 100 k
100 k - 300 k
300 k - 500 k
500 k - 1 M
5
5
2
2
3
3
5
5
5
5
2
2
3
5
10
15
0.05
0.05
0.05
0.1
0.2
0.3
0.4
0.5
0.2
0.2
0.2
0.4
0.5
0.6
1
1
0.05
0.05
0.05
0.1
0.2
0.3
0.4
0.5
0.3
0.3
0.3
0.5
0.5
0.6
1
1
50
50
± (ppm output + μV) ± (ppm output μV)/°C
0010 - 20
0020 - 40
0040 - 20 k
020 k - 50 k
050 k - 100 k
100 k - 300 k
300 k - 500 k
500 k - 1 M
150 + 20
080 + 15
012 + 2
010 + 2
010 + 2
020 + 4
100 + 10
200 + 20
002 + 1
002 + 1
002 + 1
015 + 2
015 + 4
080 + 5
080 + 5
080 + 5
02 + 1
02 + 1
02 + 1
15 + 2
15 + 4
80 + 5
80 + 5
80 + 5
50
±(ppm output+ μV)
0010 - 20
0020 - 40
0040 - 20 k
020 k - 50 k
050 k - 100 k
100 k - 300 k
300 k - 500 k
500 k - 1 M
0010 - 20
0020 - 40
0040 - 20 k
020 k - 50 k
050 k - 100 k
100 k - 300 k
300 k - 500 k
500 k - 1 M
0010 - 20
0020 - 40
0040 - 20 k
020 k - 50 k
050 k - 100 k
100 k - 300 k
300 k - 500 k
500 k - 1 M
0015 - 50
0050 - 1 k
150 + 20
080 + 15
012 + 4
015 + 5
015 + 5
030 + 10
070 + 20
150 + 50
150 + 20
080 + 15
012 + 8
015 + 10
015 + 10
030 + 15
070 + 100
150 + 100
150 + 200
080 + 150
012 + 80
015 + 100
015 + 100
030 + 400
100 + 10,000
200 + 20,000
±(ppm output + mV) ±(ppm output)/°C ±(% output)
150 + 0.5
020 + 0.5
050 + 10
015 + 5
002 + 1
010 + 2
010 + 4
080 + 15
080 + 40
080 + 100
050 + 100
015 + 30
002 + 10
010 + 20
010 + 40
080 + 150
080 + 300
080 + 500
0 50 + 1000
0 15 + 300
00 2 + 80
0 10 + 100
0 10 + 500
0 80 + 600
0 80 + 800
0 80 + 1000
50
2
50 + 10
15 + 5
05 + 2
15 + 4
20 + 4
80 + 15
80 + 40
80 + 100
50 + 100
15 + 40
04 + 15
20 + 20
20 + 40
80 + 150
80 + 300
80 + 500
50 + 1000
15 + 300
04 + 80
20 + 100
20 + 500
80 + 600
80 + 800
80 + 1000
50
5
0010 + 2
0010 + 2
0010 + 4
0030 + 10
0120 + 16
0300 ppm
0600 ppm
01200 ppm
0010 + 20
0010 + 20
0010 + 30
0030 + 50
0080 + 80
0100 + 700
0200 + 1100
0600 + 3000
0010 + 200
0010 + 200
0010 + 300
0030 + .600
0080 + 3,000
0250 + 25,000
0500 + 50,000
1000 + 110,000
0010 + 2
0010 + 1
Distortion
10 Hz-10 MHz
00.05 + 10
0.035 + 10
0.035 + 10
0.035 + 10
0.035 + 10
000.3 + 30
000.3 + 30
000 1 + 30
00.05 + 11
0.035 + 11
0.035 + 11
0.035 + 11
0.035 + 11
000.3 + 30
000.3 + 30
000 1 + 30
00.05 + 16
0.035 + 16
0.035 + 16
0.035 + 16
0.035 + 16
000.3 + 30
000.3 + 30
000 1 + 30
00.05 + 80
0.035 + 80
0.035 + 80
0.035 + 80
0.035 + 80
000.3 + 110
000.3 + 110
000 1 + 110
00.05 + 700
0.035 + 700
0.035 + 700
0.035 + 700
0.035 + 700
000.3 + 800
000.3 + 800
000 2 + 800
00.05 + 10,000
00.05 + 10,000
00.05 + 10,000
00.05 + 10,000
000.1 + 13,000
001.5 + 50,000
001.5 + 50,000
003.5 + 100,000
0.15
0.07
1-14
Introduction and Specifications
±
Table 1-8. AC Voltage Secondary Performance and Operating Characteristics (continued)
5725A Amplifier:
Range Frequency
040 - 1 k
1100 V
Voltage Range Maximum Current Limits Load Limits
5725A Amplifier: 1000 pF [Note 2]
040 Hz-5 kHz 50 mA
1100 V 05 kHz-30 kHz 70 mA 300 pF
30 kHz-100 kHz 70 mA
Notes:
1 Stability specifications are included in Absolute Uncertainty values
2. The 5725A will drive up to 1000 pF of load capacitance. Uncertainty
3. 2.2 V Range, 100 kHz-1.2 MHz only: uncertainty specifications
4. Applies from 0 °C to 40 °C
01 k - 20 k
20 k - 50 k
50 k - 100 k
2.2 V [Note 3]
22 V
220 V
1100 V 6 mA 600 pF
for the primary specifications.
specifications include loads to 300 pF and 150 pF as shown under
"Load Limits." For capacitances up to the maximum of 1000 pF, add
"Load Regulation."
cover loads to 10 mA or 1000 pF. For higher loads, load regulation
is added.
10000
40 Hz 30 Hz
1000
100
Voltage
10
3.5 V
0
50 Hz10 Hz 1 kHz 100 kHz 1 MHz 30 MHz
Stability
±1 °C [Note 1]
24 Hours 10°-40 °C
Hz ±(ppm output + mV) ±(ppm output)/°C
010 + .5
015 + 2
040 + 2
130 + 2
50 mA, 0 °C-40 °C
20 mA, 40 °C-50 °C
[Note 4]
15 Hz
Volt-Hertz Capability
Frequency
Temperature Coefficient
Adder
5
5
10
30
>50 Ω,
1000 pF
150 pF
5700A/5720A
5725A
2.2 x 107 V-Hz
5700A-03
ahp160f.eps
Figure 1-1. Volt-Hertz Capability
0°-10 °C
and
Load Regulation
[Note 2]
40°-50 °C
(ppm output + mV)
5
5
10
30
010 + 1
090 + 6
275 + 11
500 + 30
Output display formats: Voltage or dBm,
dBm reference 600 Ω.
Minimum output:: 10 % on each range
External sense: Selectable for 2.2 V, 22 V, 220 V, and
1100 V ranges; 5700A/5720A <100 kHz, 5725A <30 kHz
Settling time to full accuracy:
Frequency (Hz) Settling time (seconds)
+ 1 second for amplitude or frequency range change;
+ 2 seconds for 5700A/5720A 1100 V range;
+ 4 seconds for 5725A 1100 V range
Overshoot:: <10%
Common mode rejection: 140 dB, DC to 400 Hz
Frequency:
Ranges (Hz):
Uncertainty: ±0.01 %
Resolution: 11.999 counts
Phase lock: Selectable rear panel BNC input
Phase uncertainty (except 1100 V range):
Input voltage: 1 V to 10 V rms sine wave (do not exceed
1 V for mV ranges)
Frequency range: 10 Hz to 1.1999 MHz
Lock range: ±2 % of frequency
Lock-in time: Larger of 10/frequency or 10 msec
Phase reference: Selectable, rear panel BNC output
Range: ±180°
Phase Uncertainty (except 1100 V range):
Stability: ±0.1°
Resolution: 1°
Output level: 2.5 V rms ±0.2 V
Frequency range:
<20 7
120-120 k 5
>120 k 2
10.000-119.99
0.1200 k-1.1999 k, 1.200 k-11.999 k
12.00 k-119.99 k,120.0 k-1.1999
>30 Hz: ±1° + 0.05°/kHz), <30 Hz: ±3°
±1° at quadrature points (0°, ±90°, ±180°) elsewhere
±2°
50 kHz to 1 kHz, usable 10 Hz to 1.1999 MHz
AC Voltage Specifications 1
Distortion
Bandwidth
10 Hz-10 MHz
±(% output)
150 pF 1000 pF
0.10
0.10
0.30
0.40
0.10
0.15
0.30
0.40
1-15
5725A
Instruction Manual
1-14. Resistance Specifications
5720A
99%
Nominal
Value
0
1
1.9
10
19
100
190
1 k
1.9 k
10 k
19 k
100 k
190 k
1 M
1.9 M
10 M
19 M
100 M
Table 1-9. 5720A Series II Resistance Specifications: 99 % and 95 % Confidence Levels
99% Confidence Level
Absolute Uncertainty of Characterized Value
±5 °C from calibration temperature [Note 1]
24 Hours 90 Days 180 Days 1 Year 24 Hours 90 Days
Ω ±ppm ±ppm
50 μΩ
85
85
23
23
10
10
8
8
8
9
9
9
16
17
33
43
100
50 μΩ
95
95
25
25
11
11
9
9
9
9
11
11
18
19
37
47
110
50 μΩ
100
100
26
26
11.5
11.5
9.5
9.5
9.5
9.5
12
12
20
21
40
50
115
50 μΩ
110
110
27
27
12
12
10
10
10
10
13
13
23
24
46
55
120
Relative Uncertainty
±1 °C
50 μΩ
32
25
5
4
2
2
2
2
2
2
2
2
2.5
3
10
20
50
50 μΩ
40
33
8
7
4
4
3
3
3
3
3
3
5
6
14
24
60
5720A
95%
95 % Confidence Level
Nominal
Value
Ω ±ppm ±ppm
0
1
1.9
10
19
100
190
1 k
1.9 k
10 k
19 k
100 k
190 k
1 M
1.9 M
10 M
19 M
100 M
Note: 1. Specifications apply to displayed value. 4-wire connections, except 100 MΩ.
Absolute Uncertainty of Characterized Value
±5 °C from calibration temperature [Note 1]
24 Hours 90 Days 180 Days 1 Year 24 Hours 90 Days
40 μΩ
70
70
20
20
8
8
6.5
6.5
6.5
7.5
7.5
7.5
13
14
27
35
85
40 μΩ
80
80
21
21
9
9
7.5
7.5
7.5
7.5
9
9
15
16
31
39
95
40 μΩ
85
85
22
22
9.5
9.5
8
8
8
8
10
10
17
18
34
42
100
40 μΩ
95
95
23
23
10
10
8.5
8.5
8.5
8.5
11
11
20
21
40
57
100
Relative Uncertainty
40 μΩ
27
20
4
3.5
1.6
1.6
1.6
1.6
1.6
1.6
1.6
1.6
2
2.5
8
16
40
±1 °C
40 μΩ
35
26
7
6
3.5
3.5
2.5
2.5
2.5
2.5
2.5
2.5
4
4
12
20
50
1-16
Introduction and Specifications
Resistance Specifications 1
Table 1-10. 5700A Series II Resistance Specifications: 99 % and 95 % Confidence Levels
5700A
99%
99 % Confidence Level
Nominal
Value
Ω ±ppm ±ppm
0
1
1.9
10
19
100
190
1 k
1.9 k
10 k
19 k
100 k
190 k
1 M
1.9 M
10 M
19 M
100 M
Absolute Uncertainty of Characterized Value
±5 °C from calibration temperature [Note 1]
24 Hours 90 Days 180 Days 1 Year 24 Hours 90 Days
50 μΩ
85
85
26
24
15
15
11
11
9
9
11
11
16
17
33
43
110
50 μΩ
95
95
28
26
17
17
12
12
11
11
13
13
18
19
37
47
120
50 μΩ
100
100
30
28
18
18
13
13
12
12
14
14
20
21
40
50
125
50 μΩ
110
110
33
31
20
20
15
15
14
14
16
16
23
24
46
55
130
Relative Uncertainty
50 μΩ
32
25
5
4
2
2
2
2
2
2
2
2
2.5
3.5
10
20
50
±1 °C
50 μΩ
40
33
8
7
4
4
3.5
3.5
3.5
3.5
3.5
3.5
5
6
14
24
60
5700A
95%
95 % Confidence Level
Nominal
Value
Ω ±ppm ±ppm
0
1
1.9
10
19
100
190
1 k
1.9 k
10 k
19 k
100 k
190 k
1 M
1.9 M
10 M
19 M
100 M
Note: 1. Specifications apply to displayed value. 4-wire connections, except 100 MΩ.
Absolute Uncertainty of Characterized Value
±5 °C from calibration temperature [Note 1]
24 Hours 90 Days 180 Days 1 Year 24 Hours 90 Days
50 μΩ
70
70
21
20
13
13
9
9
7.5
7.5
9
9
13
14
27
35
90
50 μΩ
80
80
23
22
14
14
10
10
9.5
9.5
11
11
15
16
31
39
100
50 μΩ
85
85
27
24
15
15
11
11
10.5
10.5
12
12
17
18
34
42
105
50 μΩ
95
95
28
27
17
17
13
13
12
12
14
14
20
21
40
47
110
Relative Uncertainty
50 μΩ
32
25
5
4
2
2
2
2
2
2
2
2
2.5
3
10
20
50
±1 °C
50 μΩ
40
33
8
7
4
4
3.5
3.5
3.5
3.5
3.5
3.5
5
6
14
24
60
1-17
5725A
m
m
m
m
m
m
m
m
m
m
Instruction Manual
Nominal
Value
0 ⎯ ⎯ ⎯
1 32 4 5
1.9 25 6 7
10 5 2 3
19 4 2 3
100 2 2 3
190 2 2 3
1 k 2 2 3
1.9 k 2 2 3
Table 1-11. Resistance Secondary Performance Specifications and Operating Characteristics
Stability
±1 °C
[Note 1]
24 Hours 40°-50 °C 0.1Ω 1Ω
Ω ±ppm ±ppm/°C mA mA ±ppm ±mΩ
Temperature
Coefficient Adder
[Note 2]
10°-40 °C 0°-10 °C
and
Full Spec
Load Range
[Note 3] to Nominal
00
8 - 500 500 ⎯
00
8 - 100 700 500
00
8 - 100 500 500
00
8 - 11
00
8 - 11 160 300
00
8 - 11 70 150
00
8 - 11 50 150
00
1 - 2 22 150
00
1 - 1.5 16 150
Maximum
Peak
Current
Characterized
220 300
Maximum
Difference
of
Value
Two-Wire Adder
active
compensation
[Note 4]
Lead Resistance
4 V
μ
2 +
Im
4 V
μ
2 +
I
4 V
μ
2 +
I
4 V
μ
2 +
Im
4 V
μ
2 +
I
4 V
μ
2 +
I
4 V
μ
2 +
I
10 15
10 15
4 +
4 +
4 +
4 +
4 +
4 +
4 +
4 V
μ
Im
4 V
μ
I
4 V
μ
I
4 V
μ
Im
4 V
μ
I
4 V
μ
I
4 V
μ
I
10 k 2 2 3 100 - 500 μA 7 150
0
19 k 2 2 3
100 k 2 2 3 10 - 100 μA 1 150 Im= Current
190 k 2 2 3 00 5 - 50 μA 500 μA 150
1 M 2.5 2.5 6 00 5 - 20 μA 100 μA 200
1.9 M 3.5 3 10 02.5 - 10 μA 50 μA 200
10 M 10 5 20 00.5 - 2 μA 10 μA 300
19 M 20 8 40 0.25 - 1 μA 5 μA 300
100 M 50 12 100 0 50 - 200 nA 1 μA 500
50 - 250 μA 5 150
50 60
100 120
produced by
Ohmmeter
Notes:
1. Stability specifications are included in the Absolute Uncertainty values in the primary specification tables.
2. Temperature coefficient is an adder to uncertainty specifications that does not apply unless operated more
than 5 °C from calibration temperature, or calibrated outside the range 19 °C to 24 °C. Two examples:
• Calibrate at 20 °C: Temperature coefficient adder is not required unless operated below 15 °C or
above 25 °C.
• Calibrate at 26 °C: Add 2 °C temperature coefficient adder. Additional temperature coefficient adder is
not required unless operated below 21 °C or above 31 °C.
3. Refer to current derating factors table for loads outside of this range.
4. Active two-wire compensation may be selected for values less than 100 kΩ, with either the front panel or
the meter input terminals as reference plane. Active compensation is limited to 11 mA load, and to 2 V
burden. Two-wire compensation can be used only with Ω-meters that source continuous (not pulsed) dc
current.
1-18
Introduction and Specifications
Table 1-12. Current Derating Factors
Nominal Value Value of Derating Factor K for Over or Under Current
Four-Wire
I < I
L
[Note 1]
0.3
300
160
30
16
3.5
2.5
0.4
0.4
50
50
7.5
4.0
1.0
0.53
0.2
0.53
0.1
Notes:
Ω
SHORT
1
1.9
10
19
100
190
1 k
1.9 k
10 k
19 k
100 k
190 k
1 M
1.9 M
10 M
19 M
100 M
Tw
o-Wire Comp
I < I
[Note 1]
4.4
4.4
4.4
4.4
4.4
4.4
4.4
4.4
4.4
5000
5000
⎯
⎯
⎯
⎯
⎯
⎯
L
Resistance Specifications 1
Four-Wire
<
I
U
[Note 2]
I < I
⎯
4 x10
1.5 x 10
1.6 x 10
3 x 10
1 x 10
1.9 x 10
0.1
0.19
2.0
3.8
2 x 10
3.8 x 10
1.5 x 10
2.9 x 10
1 x 10
1.9 x 10
⎯
max
-5
-3
-2
-5
-3
-4
-3
-2
-5
-4
-4
-3
I < I
1. For
, errors occur due to thermally generated voltages within the 5720A. Use the following
L
equation to determine the error, and add this error to the corresponding uncertainty or stability
specification.
Error = K(
I
L
- I)/( I
L
x I)
Where: Error is in mΩ for all two-wire comp values and four-wire short, and in ppm for the remaining
four-w
ire values.
K
is the constant from the above table;
2. For
I and I
I and I
I
U
are expressed in mA for short to 1.9 kΩ;
L
are expressed in μA for 10 kΩ to 100 MΩ
L
< I < I
errors occur due to self-heating of the resistors in the calibrator. Use the following
MAX
equation to determine the error in ppm and add this error to the corresponding uncertainty or stability
spec
ification.
2
Error
Where: K
I and I
I and I
in ppm = K(I
is the constant from the above table;
are expressed in mA for short to 19 kΩ;
U
are expressed in μA for 100 kΩ to 100 MΩ
U
2
-I
)
U
1-19
5725A
Instruction Manual
1-15. DC Current Specifications
5720A
99%
Range Resolution
220 μA
2.2 mA
22 mA
220 mA
2.2 A
[Note 1]
11 A 10 330 + 470 340 + 480 350 + 480 360 + 480 100 + 130 110 + 130
Table 1-13. 5720A Series II DC Current Specifications: 99 % and 95 % Confidence Levels
99 % Confidence Level
Absolute Uncertainty
±5 °C from calibration temperature.
For fields strengths >0.4 V/m but ≤3 V/m,
add 1 % of range.
24 Hours 90 Days 180 Days 1 Year 24 Hours 90 Days
nA ± (ppm output + nA) ± (ppm output + nA)
0.1
1
10
μA ± (ppm output + μA) ± (ppm output + μA)
0.1
1
040 + 7
030 + 8
030 + 50
040 + 0.8
060 + 15
5725A Amplifier:
042 + 7
035 + 8
035 + 50
045 + 0.8
070 + 15
045 + 7
037 + 8
037 + 50
047 + 0.8
080 + 15
050 + 7
040 + 8
040 + 50
050 + 0.8
090 + 15
Relative Uncertainty ±1 °C
024 + 7
024 + 8
024 + 50
026 + 0.5
040 + 12
026 + 7
026 + 8
026 + 50
030 + 0.5
045 + 12
5720A
95%
95 % Confidence Level
Absolute Uncertainty
Range Resolution
nA ± (ppm output + nA) ± (ppm output + nA)
220 μA
2.2 mA
22 mA
220 mA
2.2 A
[Note 1]
11 A 10 330 + 470 340 + 480 350 + 480 360 + 480 100 + 130 110 + 130
Note: Maximum output from calibrator terminals is 2.2 A. Uncertainty specifications for 220 mA and 2.2 mA
0.1
1
10
μA ± (ppm output + μA) ± (ppm output + μA)
0.1
1
032 + 6
025 + 7
025 + 40
035 + 0.7
050 + 12
±5 °C from calibration temperature
For fields strengths >0.4 V/m but ≤3 V/m,
add 1 % of range.
24 Hours 90 Days 180 Days 1 Year 24 Hours 90 Days
035 + 6
030 + 7
030 + 40
040 + 0.7
060 + 12
5725A Amplifier:
037 + 6
033 + 7
033 + 40
042 + 0.7
070 + 12
040 + 6
035 + 7
035 + 40
045 + 0.7
080 + 12
ranges are increased by a factor of 1.3 when supplied through 5725A terminals.
Specifications are otherwise identical for all output locations.
1. Add to uncertainty specifications:
±200 x
±10 x
2
I
ppm for >100 mA on 220 mA range
2
I
ppm for >1 A on 2.2 A range
Relativ
020 + 6
020 + 7
020 + 40
020 + 0.7
032 + 12
e Uncertainty ±1 °C
022 + 6
022 + 7
022 + 40
025 + 0.7
040 + 12
1-20
Introduction and Specifications
DC Current Specifications 1
Table 1-14. 5700A Series II DC Current Specifications: 99 % and 95 % Confidence Levels
5700A
99%
99 % Confidence Level
bsolute Uncertainty
A
±5 °C from calibration temperature
Range Resolution
nA ± (ppm output + nA) ± (ppm output + nA)
220 μA
2.2 mA
22 mA
220 mA
2.2 A
[Note 1]
5725A Amplifier:
11 A 10 330 + 470 340 + 480 350 + 480 360 + 480 100 + 130 110 + 130
0.1
1
10
μA ± (ppm output + μA) ± (ppm output + μA)
0.1
1
For fields strengths >0.4 V/m but ≤3 V/m,
add 1% of range.
24 Hours 90 Days 180 Days 1 Year 24 Hours 90 Days
045 + 10
045 + 10
045 + 100
055 + 1
075 + 30
050 + 10
050 + 10
050 + 100
060 + 1
080 + 30
055 + 10
055 + 10
055 + 100
065 + 1
090 + 30
060 + 10
060 + 10
060 + 100
070 + 1
095 + 30
Relative Uncertainty ±1 °C
024 + 2
024 + 5
024 + 50
026 + .3
040 + 7
026 + 2
026 + 5
026 + 50
030 + .3
045 + 7
5700A
95%
95 % Confidence Level
A
Range Resolution
nA
220 μA
2.2 mA
22 mA
220 mA
2.2 A
[Note 1]
5725A Amplifier:
11 A 10 330 + 470 340 + 480 350 + 480 360 + 480 100 + 130 110 + 130
Note: Maximum output from the calibrator’s terminals is 2.2 A. Uncertainty specifications for 220 mA and
0.1
1
10
μA ± (ppm output + μA)
0.1
1
035 + 8
035 + 8
035 + 80
045 + 0.8
060 + 25
±5 °C from calibration temperature
For fields strengths >0.4 V/m but ≤3 V/m,
24 Hours 90 Days 180 Days 1 Year 24 Hours 90 Days
bsolute Uncertainty
add 1 % of range.
± (ppm output + nA
040 + 8
040 + 8
040 + 80
050 + 0.8
065 + 25
045 + 8
045 + 8
045 + 80
055 + 0.8
075 + 25
) ± (ppm output + nA)
050 + 8
050 + 8
050 + 80
± (ppm output + μA)
060 + 0.8
080 + 25
2.2 mA ranges are increased by a factor of 1.3 when supplied through 5725A terminals.
Specifications are otherwise identical for all output locations.
1. Add to uncertainty specifications:
±200 x
±10 x
2
I
ppm for >100 mA on 220 mA range
2
I
ppm for >1A on 2.2A range
Relative Uncertainty ±1 °C
020 + 1.6
020 + 4
020 + 80
022 + 0.25
035 + 6
022 + 1.6
022 + 4
022 + 80
025 + 0.25
040 + 6
1-21
5725A
Instruction Manual
Range Stability
220 μA
2.2 mA
22 mA
220 mA
2.2 A
5725A ± (ppm output
11 A
Notes:
Maximum output from the calibrator’s terminals is 2.2 A. Uncertainty specifications for 220 mA and 2.2 mA
ranges are increased by a factor of 1.3 when supplied through 5725A terminals.
Table 1-15. DC Current Secondary Performance Specifications and Operating Characteristics
Temperature
Coefficient [Note 2]
10 °-40 °C 0 °-10 °C
±1 °C [Note 1]
24 Hours 40 °-50 °C [Note 4] pk-pk RMS
± (ppm output
+ nA)
05 + 1
05 + 5
05 + 50
08 + 300
09 + 7 μA
+ μA)
25 + 100 20 + 75 30 + 120
± (ppm output + nA)/ °C ±nA/V Ω ppm output
1 + 0.40
1 + 2
1 + 20
1 + 200
1 + 2.5 μΑ
± (ppm output + μA)/
and
3 + 1
3 + 10
3 + 100
3 + 1 μA
3 + 10 μA
°C
Compliance
Limits
10
10
10
10
3 [Note 5]
4
Burden
Voltage
Adder
[Note 3]
0.2
0.2
10
100
2 μA
4 15 + 70 175
Maximum
Load for
Full
Accuracy
20k
2k
200
20
2
Bandwidth
0.1-10 Hz
06 + .9
06 + 5
06 + 50
09 + 300
12 + 1.5 μA
ppm output
Noise
Bandwidth
+ nA
+ μA
0 Hz-10 kHz
nA
10
10
50
500
20 μA
μA
1. Stability specifications are included in the Absolute Uncertainty values for the primary specifications.
2. Temperature coefficient is an adder to uncertainty specifications. It does not apply unless operating more
than ±5 °C from calibration temperature.
3. Burden voltage adder is an adder to uncertainty specifications that does not apply unless burden voltage is
greater than 0.5 V.
4. For higher loads, multiply uncertainty specification by:
The calibrator’s compliance limit is 2 V for outputs from 1 A to 2.2 A. 5725A Amplifier may be used in range-
5.
1
+
0.1 x actual load
maximum load for full accuracy
lock mode down to 0 A.
Minimum output: 0 for all ranges, including 5725A.
Settling time to full accuracy: 1 second for mA and mA ranges; 3 seconds for 2.2 A range; 6 seconds for 11 A
range; + 1 second for range or polarity change
Overshoot: <5 %
1-22
1-16. AC Current Specifications
Table 1-16. 5720A Series II AC Current Specifications: 99 % Confidence Level
5720A
99%
99 % Confidence Level
Range Resolution Frequency
Hz ± (ppm output + nA) ± (ppm output + nA)
010 - 20
220 μA 1 nA
2.2 mA 10 nA
22 mA 100 nA
020 - 40
040 - 1 k
01k - 5 k
05k - 10 k
010 - 20
020 - 40
040 - 1 k
01k - 5 k
05k - 10 k
010 - 20
020 - 40
040 - 1 k
01k - 5 k
05k - 10 k
Hz ± (ppm output + μA) ± (ppm output + μA)
010 - 20
220 mA 1 μA
2.2 A 10 μA
11 A 100 μA
020 - 40
040 - 1 k
01k - 5 k
05k - 10 k
020 - 1 k
01 k - 5 k
05 k - 10 k
040 - 1 k
01 k - 5 k
05 k - 10 k
0260 + 20
0170 + 12
0120 + 10
0300 + 15
1000 + 80
0260 + 50
0170 + 40
0120 + 40
0210 + 130
1000 + 800
0260 + 500
0170 + 400
0120 + 400
0210 + 700
1000 + 6000
0260 + 5
0170 + 4
0120 + 3
0210 + 4
1000 + 12
0290 + 40
0440 + 100
6000 + 200
5725A Amplifier:
0370 + 170
0800 + 380
3000 + 750
±5 °C from calibration temperature
For fields strengths >0.4 V/m but
24 Hours 90 Days 180 Days 1 Year 24 Hours 90 Days
Absolute Uncertainty
add 1 % of range.
0280 + 20
0180 + 12
0130 + 10
0320 + 15
1100 + 80
0280 + 50
0180 + 40
0130 + 40
0220 + 130
1100 + 800
0280 + 500
0180 + 400
0130 + 400
0220 + 700
1100 + 6000
0280 + 5
0180 + 4
0130 + 3
0220 + 4
1100 + 12
0300 + 40
0460 + 100
7000 + 200
0400 + 170
0850 + 380
3300 + 750
0290 + 20
0190 + 12
0135 + 10
0340 + 15
1200 + 80
0290 + 50
0190 + 40
0135 + 40
0230 + 130
1200 + 800
0290 + 500
0190 + 400
0135 + 400
0230 + 700
1200 + 6000
0290 + 5
0190 + 4
0135 + 3
0230 + 4
1200 + 12
0310 + 40
0480 + 100
7500 + 200
0440 + 170
0900 + 380
3500 + 750
≤3 V/m,
0300 + 20
0200 + 12
0140 + 10
0350 + 15
1300 + 80
0300 + 50
0200 + 40
0140 + 40
0240 + 130
1300 + 800
0300 + 500
0200 + 400
0140 + 400
0240 + 700
1300 + 6000
0300 + 5
0200 + 4
0140 + 3
0240 + 4
1300 + 12
0320 + 40
0500 + 100
8000 + 200
0460 + 170
0950 + 380
3600 + 750
Introduction and Specifications
AC Current Specifications 1
e Uncertainty
Relativ
±1 °C
0260 + 20
0130 + 12
0100 + 10
0250 + 15
0900 + 80
0260 + 50
0130 + 40
0100 + 40
0250 + 130
0900 + 800
0260 + 500
0130 + 400
0100 + 400
0250 + 700
0900 + 6000
0260 + 5
0130 + 4
0100 + 3
0250 + 4
0900 + 12
0300 + 40
0500 + 100
6000 + 200
0300 + 170
0700 + 380
2800 + 750
0280 + 20
0150 + 12
0110 + 10
0280 + 15
01000 + 80
0280 + 50
0150 + 40
0110 + 40
0280 + 130
1000 + 800
0280 + 500
0150 + 400
0110 + 400
0280 + 700
1000 + 6000
0280 + 5
0150 + 4
0110 + 3
0280 + 4
1000 + 12
0350 + 40
0520 + 100
7000 + 200
0330 + 170
0800 + 380
3200 + 750
Note: Maximum output from the calibrator’s terminals is 2.2 A. Uncertainty specifications for 220 μA and 2.2 mA
ranges are increased by a factor of 1.3 plus 2 μA when supplied through 5725A terminals. Specifications are
otherwise identical for all output locations.
1-23
5725A
Instruction Manual
5720A
95%
Range Resolution Frequency
220 μA 1 nA
2.2 mA 10 nA
22 mA 100 nA
220 mA 1 μA
2.2 A 10 μA
11 A 100 μA
Note: Maximum output from the calibrator’s terminals is 2.2 A. Uncertainty specifications for 220 μA and
2.2 mA ranges are increased by 1.3 x plus 2 μA when supplied through 5725A terminals. Specifications are
otherwise identical for all output locations.
Table 1-17. 5720A Series II AC Current Specifications: 95 % Confidence Level
95 % Confidence Level
Absolute Uncertainty
±5 °C from calibration temperature
For fields strengths >0.4 V/m but ≤3 V/m,
add 1 % of range.
24 Hours 90 Days 180 Days 1 Year 24 Hours 90 Days
Hz ± (ppm output + nA) ± (ppm output + nA)
010 - 20
020 - 40
040 - 1 k
01k - 5 k
05k - 10 k
010 - 20
020 - 40
040 - 1 k
01k - 5 k
05k - 10 k
010 - 20
020 - 40
040 - 1 k
01k - 5 k
05k - 10 k
0210 + 16
0130 + 10
0100 + 8
0240 + 12
0800 + 65
0210 + 40
0140 + 35
0100 + 35
0170 + 110
0800 + 650
0210 + 400
0130 + 350
0100 + 350
0170 + 550
0800 + 5000
0230 + 16
0140 + 10
0110 + 8
0250 + 12
0900 + 65
0230 + 40
0140 + 35
0110 + 35
0180 + 110
0900 + 650
0230 + 400
0140 + 350
0110 + 350
0180 + 550
0900 + 5000
0240 + 16
0150 + 10
0115 + 8
0270 + 12
1000 + 65
0240 + 40
0150 + 35
0115 + 35
0190 + 110
1000 + 650
0240 + 400
0150 + 350
0115 + 350
0190 + 550
1000 + 5000
0250 + 16
0160 + 10
0120 + 8
0280 + 12
1100 + 65
0250 + 40
0160 + 35
0120 + 35
0200 + 110
1100 + 650
0250 + 400
0160 + 350
0120 + 350
0200 + 550
1100 + 5000
Hz ± (ppm output + μA) ± (ppm output + μA)
010 - 20
020 - 40
040 - 1 k
01k - 5 k
05k - 10 k
020 - 1 k
01 k - 5 k
05 k - 10 k
0210 + 4
0130 + 3.5
0100 + 2.5
0170 + 3.5
0800 + 10
0230 + 35
0350 + 80
5000 + 160
0230 + 4
0140 + 3.5
0110 + 2.5
0180 + 3.5
0900 + 10
0240 + 35
0390 + 80
6000 + 160
0240 + 4
0150 + 3.5
0115 + 2.5
0190 + 3.5
1000 + 10
0250 + 35
0420 + 80
6500 + 160
0250 + 4
0160 + 3.5
0120 + 2.5
0200 + 3.5
1100 + 10
0260 + 35
0450 + 80
7000 + 160
5725A Amplifier:
040 - 1 k
01 k - 5 k
05 k - 10 k
0370 + 170
0800 + 380
3000 + 750
0400 + 170
0850 + 380
3300 + 750
0440 + 170
0900 + 380
3500 + 750
0460 + 170
0950 + 380
3600 + 750
Relative Uncertainty
±1 °C
0210 + 16
0110 + 10
0080 + 8
0200 + 12
0700 + 65
0210 + 40
0110 + 35
0080 + 35
0200 + 110
0700 + 650
0210 + 400
0110 + 350
0080 + 350
0200 + 550
0700 + 5000
0210 + 4
0110 + 3.5
0080 + 2.5
0200 + 3.5
0700 + 10
0250 + 35
0400 + 80
5000 + 160
0300 + 170
0700 + 380
2800 + 750
0230 + 16
0130 + 10
0090 + 8
0230 + 12
0800 + 65
0230 + 40
0130 + 35
0090 + 35
0230 + 110
0800 + 650
0230 + 400
0130 + 350
0090 + 350
0230 + 550
0800 + 5000
0230 + 4
0130 + 3.5
090 + 2.5
0230 + 3.5
0800 + 10
0300 + 35
0440 + 80
6000 + 160
0330 + 170
0800 + 380
3200 + 750
1-24
5700A
99%
Introduction and Specifications
AC Current Specifications 1
Table 1-18. 5700A Series II AC Current Specifications: 99 % Confidence Level
99 % Confidence Level
Range Resolution Frequency
±5 °C from calibration temperature
Relative Uncertainty
±1 °C
For fields strengths >0.4 V/m but ≤3 V/m,
add 1 % of range.
24 Hours 90 Days 180 Days 1 Year 24 Hours 90 Days
Hz ± (ppm output + nA) ± (ppm output + nA)
Absolute Uncertainty
220 μA 1 nA
2.2 mA 10 nA
22 mA 100 nA
010 - 20
020 - 40
040 - 1 k
01k - 5 k
5k - 10 k
010 - 20
020 - 40
040 - 1 k
01k - 5 k
5k - 10 k
010 - 20
020 - 40
040 - 1 k
01k - 5 k
5k - 10 k
0650 + 30
0350 + 25
0120 + 20
0500 + 50
1500 + 100
0650 + 50
0350 + 40
0120 + 40
0500 + 500
1500 + 1000
0650 + 500
0350 + 400
0120 + 400
0500 + 5000
1500 + 10,000
0700 + 30
0380 + 25
0140 + 20
0600 + 50
1600 + 100
0700 + 50
0380 + 40
0140 + 40
0600 + 500
1600 + 1000
0700 + 500
0380 + 400
0140 + 400
0600 + 5000
1600 + 10,000
0750 + 30
0410 + 25
0150 + 20
0650 + 50
1700 + 100
0750 + 50
0410 + 40
0150 + 40
0650 + 500
1700 + 1000
0750 + 500
0410 + 400
0150 + 400
0650 + 5000
1700 + 10,000
00 800 + 30
00 420 + 25
00 160 + 20
00 700 + 50
0 1800 + 100
00 800 + 50
0 0420 + 40
00 160 + 40
00 700 + 500
0 1800 + 1000
00 800 + 500
00 420 + 400
00 160 + 400
00 700 + 5000
0 1800 + 10,000
0450 + 30
0270 + 25
0110 + 20
0450 + 50
1400 + 100
0450 + 50
0270 + 40
0110 + 40
0450 + 500
1400 + 1000
0450 + 500
0270 + 400
0110 + 400
0450 + 5000
1400 + 10,000
0500 + 30
0300 + 25
0120 + 20
0500 + 50
1500 + 100
0500 + 50
0300 + 40
0120 + 40
0500 + 500
1500 + 1000
0500 + 500
0300 + 400
0120 + 400
0500 + 5000
1500 +
10,000
Hz ± (ppm output + μA) ± (ppm output + μA)
220 mA 1 μA
2.2 A 10 μA
010 - 20
020 - 40
040 - 1 k
01k - 5 k
5k - 10 k
20 - 1 k
1 k - 5 k
5 k - 10 k
0650 + 5
0350 + 4
0120 + 4
0500 + 50
1500 + 100
0600 + 40
0700 + 100
8000 + 200
0700 + 5
0380 + 4
0150 + 4
0600 + 50
1600 + 100
0650 + 40
0750 + 100
9000 + 200
0750 + 5
0410 + 4
0170 + 4
0650 + 50
1700 + 100
0700 + 40
0800 + 100
9500 + 200
00 800 + 5
00 420 + 4
00 180 + 4
0 700 + 50
0 1800 + 100
0 750 + 40
00 850 + 100
10,000 + 200
0450 + 5
0280 + 4
0110 + 4
0450 + 50
1400 + 100
0600 + 40
0650 + 100
7500 + 200
0500 + 5
0300 + 4
0130 + 4
0500 + 50
1500 + 100
0650 + 40
0750 + 100
8500 + 200
5725A Amplifier:
11 A 100 μA
40 - 1 k
1 k - 5 k
5 k - 10 k
0370 + 170
0800 + 380
3000 + 750
400 + 170
850 + 380
3300 + 750
0440 + 170
0900 + 380
3500 + 750
00 460 + 170
00 950 + 380
0 3600 + 750
0300 + 170
0700 + 380
2800 + 750
0330 + 170
0800 + 380
3200 + 750
Note: Maximum output from the calibrator’s terminals is 2.2 A. Uncertainty specifications for 220 μA and 2.2 mA
ranges are increased by 1.3 x plus 2 μA when supplied through 5725A terminals. Specifications are otherwise
identical for all output locations.
1-25
5725A
Instruction Manual
5700A
95%
Range Resolution Frequency
220 μA 1 nA
2.2 mA 10 nA
22 mA 100 nA
220 mA 1 μA
2.2 A 10 μA
11 A 100 μA
Note: Maximum output from the calibrator’s terminals is 2.2 A. Uncertainty specifications for 220 μA and
2.2 mA ranges are increased by a factor of 1.3 plus 2 μA when supplied through 5725A terminals.
Specifications are otherwise identical for all output locations.
Table 1-19. 5700A Series II AC Current Specifications: 95 % Confidence Level
95 % Confidence Level
Absolute Uncertainty
±5 °C from calibration temperature
For fields strengths >0.4 V/m but ≤3 V/m,
add 1 % of range.
24 Hours 90 Days 180 Days 1 Year 24 Hours 90 Days
Hz ± (ppm output + nA) ± (ppm output + nA)
010 - 20
020 - 40
040 - 1 k
01k - 5 k
5k - 10 k
010 - 20
020 - 40
040 - 1 k
01k - 5 k
5k - 10 k
010 - 20
020 - 40
040 - 1 k
01k - 5 k
5k - 10 k
0550 + 25
0280 + 20
0100 + 16
0400 + 40
1300 + 80
0550 + 40
0280 + 35
0100 + 35
0400 + 400
1300 + 800
0550 + 400
0280 + 350
0100 + 350
0400 + 4000
1300 + 8000
Hz ± (ppm output + μA) ± (ppm output + μA)
010 - 20
020 - 40
040 - 1 k
01k - 5 k
5k - 10 k
20 - 1 k
1 k - 5 k
5 k - 10 k
0550 + 4
0280 + 3.5
0100 + 3.5
0400 + 40
1300 + 80
0500 + 35
0600 + 80
6500 + 160
5725A Amplifier:
40 - 1 k
1 k - 5 k
5 k - 10 k
0370 + 170
0800 + 380
3000 + 750
0600 + 25
0310 + 20
0120 + 16
0500 + 40
1400 + 80
0600 + 40
0310 + 35
0120 + 35
0500 + 400
1400 + 800
0600 + 400
0310 + 350
0120 + 350
0500 + 4000
1400 + 8000
0600 + 4
0310 + 3.5
0120 + 3.5
0500 + 40
1400 + 80
0550 + 35
0650 + 80
7500 + 160
0400 + 170
0850 + 380
3300 + 750
0650 + 25
0330 + 20
0130 + 16
0550 + 40
1500 + 80
0650 + 40
0330 + 35
0130 + 35
0550 + 400
1500 + 800
0650 + 400
0330 + 350
0130 + 350
0550 + 4000
1500 + 8000
0650 + 4
0330 + 3.5
0130 + 3.5
0550 + 40
1500 + 80
0600 + 35
0700 + 80
8000 + 1600
0440 + 170
0900 + 380
3500 + 750
0700 + 25
0350 + 20
0140 + 16
0600 + 40
1600 + 80
0700 + 40
0350 + 35
0140 + 35
0600 + 400
1600 + 800
0700 + 400
0350 + 350
0140 + 350
0600 + 4000
1600 + 8000
0700 + 4
0350 + 3.5
0140 + 3.5
0600 + 40
1600 + 80
0650 + 35
0750 + 80
8500 + 160
0460 + 170
0950 + 380
3600 + 750
Relative Uncertainty
±1 °C
0375 + 25
0220 + 20
090 + 16
0375 + 40
1200 + 80
0375 + 40
0220 + 35
0090 + 35
0375 + 400
1200 + 800
0375 + 400
0220 + 350
0090 + 350
0375 + 4000
1200 + 8000
0375 + 4
0220 + 3.5
0090 + 3.5
0375 + 40
1200 + 80
0500 + 35
0550 + 80
6000 + 160
0300 + 170
0700 + 380
2800 + 750
0400 + 25
0250 + 20
0100 + 16
0400 + 40
1200 +80
0400 + 40
0250 + 35
0100 + 35
0400 + 400
1200 + 800
0400 + 400
0250 + 350
0100 + 350
0400 + 4000
1200 + 8000
0400 + 4
0250 + 3.5
0100 + 3.5
0400 + 40
1200 + 80
0550 + 35
0650 + 80
7000 + 160
0330 + 170
0800 + 380
3200 + 750
1-26
Introduction and Specifications
Table 1-20. AC Current Secondary Performance Specifications and Operating Characteristics
Stability
±1 °C [Note 1]
Range Frequency 24 Hours 10°-40 °C 0°-10 °C and
Hz ± (ppm output + nA) ± (ppm output + nA)/°C V rms Ω ± (% output + μA)
220 μA 010 - 20
020 - 40
040 - 1 k
01k - 5 k
05k - 10 k
2.2 mA 010 - 20
020 - 40
040 - 1 k
01k - 5 k
05k - 10 k
22 mA 010 - 20
020 - 40
040 - 1 k
01k - 5 k
05k - 10 k
Hz ± (ppmutput + μA) ± (ppm output + μA)/°C
220 mA 010 - 20
020 - 40
040 - 1 k
01k - 5 k
05k - 10 k
2.2 A 20 - 1 k
1 k - 5 k
5 k - 10 k
5725A Amplifier: ± (% output)
11 A 40 - 1 k
1 k - 5 k
5 k - 10 k
Notes:
Maximum output from 5720A terminals is 2.2 A. Uncertainty specifications for 220
factor of 1.3, plus 2
1. Stability specifications are included in the Absolute Uncertainty values for the primary specifications.
2. Temperature coefficient is an adder to uncertainty specifications that does not apply unless operating more than
calibration temperature.
3. For larger resistive loads multiply uncertainty specifications by:
4. 1.5 V compliance limit above 1 A. 5725A Amplifier may be used in range-lock mode down to 1 A.
5. For resistive loads within rated compliance voltage limits.
6. For outputs from the Aux Current terminals, the maximum resistive load for full accuracy is 1 k
multiply the uncertainty as described in Note 3.
Minimum output: 9
Inductive load limits: 400
Power factors: 5700A/5720A, 0.9 to 1; 5725A, 0.1 to 1. Subject to compliance voltage limits.
Frequency:
Range (Hz): 10.000-11.999, 12.00-119.99, 120.0-1199.9, 1.200 k-10.000 k
Uncertainty:
Resolution: 11,999 counts
Settling time to full accuracy: 5 seconds for 5700A/5720A ranges; 6 seconds for 5725A 11 A range; +1 second for amplitude
or frequency range change.
Overshoot: <10 %
μA when supplied through 5725A terminals. Specifications are otherwise identical for all output locations.
μA for 220 μA range, 10 % on all other ranges. 1 A minimum for 5725A.
±0.01 %
150 + 5
080 + 5
030 + 3
050 + 20
400 + 100
150 + 5
080 + 5
030 + 3
050 + 20
400 + 100
150 + 50
080 + 50
030 + 30
050 + 500
400 + 1000
150 + 0.5
080 + 0.5
030 + 0.3
050 + 3
400 + 5
050 + 5
080 + 20
800 + 50
075 + 100
100 + 150
200 + 300
μH (5700A/5720A, or 5725A). 20 μH for 5700A/5720A output >1 A.
Temperature Coefficient
[Note 2]
40°-50 °C
050 + 5
020 + 5
004 + 0.5
010 + 1
020 + 100
050 + 5
020 + 4
004 + 1
010 + 100
050 + 400
050 + 10
020 + 10
004 + 10
010 + 500
050 + 1000
050 + 0.05
020 + 0.05
004 + 0.1
010 + 2
050 + 5
004 + 1
010 + 5
050 + 10
020 + 75
040 + 75
100 + 75
050 + 5
020 + 5
010 + 0.5
020 + 1
020 + 100
050 + 5
020 + 4
010 + 2
020 + 100
050 + 400
050 + 10
020 + 10
010 + 20
020 + 400
050 + 1000
050 + 0.05
020 + 0.05
010 + 0.1
020 + 2
050 + 5
010 + 1
020 + 5
050 + 10
030 + 75
050 + 75
100 + 75
(
maximum load for full accuracy
Compliance
Limits
For Full
7 2k
7 500 0.05 + 0.1
7 150 0.05 + 0.1
7 15 0.05 + 10
1.4
[Note 4]
3 3 0.05
μA and 2.2 mA ranges are increased by a
actual load
AC Current Specifications 1
Bandwidth
10 Hz-50 kHz
<0.5V Burden
Noise and
Distortion
0.05 + 0.1
0.05 + 0.1
0.05 + 0.1
0.25 + 0.5
00.5 + 1
0.05 + 0.1
0.05 + 0.1
0.25 + 0.5
00.5 + 1
0.05 + 0.1
0.05 + 0.1
0.25 + 0.5
00.5 + 1
0.05 + 10
0.05 + 10
0.25 + 50
00.5 + 100
0.3 + 500
0 1 + 1 mA
0.12
0.5
[Note 5]
±5 °C from
Maximum
Resistive
Load
Accuracy
[Note 3]
[Note 6]
0.5 0.5 + 100
2
)
Ω. For larger resistive loads,
1-27
5725A
Instruction Manual
1-17. Wideband AC Voltage (Option 5700-03) Specifications
Specifications apply to the end of the cable and 50 Ω termination used for calibration
1.1 mV -46 10 nV 0.4 + 0.4 00.5 + 0.4 00.6 + 0.4 0.8 + 2
3 mV -37 10 nV 0.4 + 1 0.45 + 1 00.5 + 1 0.7 + 3
11 mV -26 100 nV 0.2 + 4 0.35 + 4 00.5 + 4 0.7 + 8
33 mV -17 100 nV 0.2 + 10 00.3 + 10 0.45 + 10 0.6 + 16
110 mV -6.2 1 μV 0.2 + 40 00.3 + 40 0.45 + 40 0.6 + 40
330 mV +3.4 1 μV 0.2 + 100 0 2.5 + 100 0.35 + 100 0.5 + 100
1.1 V +14 10 μV 0.2 + 400 0.25 + 400 0.35 + 400 0.5 + 400
3.5 V +24 10 μV 0.15 + 500 00.2 + 500 00.3 + 500 0.4 + 500
Table 1-21. Wideband AC Voltage (Option 5700-03) Specifications
Absolute Uncertainty
Range Resolution
Volts dBm 24 Hours 90 Days 180 Days 1 Year
±5 °C from calibration temperature
30 Hz-500 kHz
± (% output + μV)
Settling
Frequency
00 10 - 30 0.01 0.3 0.3 0.3 100 7 -40
00 30 - 120 0.01 0.1 0.1 0.1 100 7 -40
0 120 - 1.2 k 0.1 0.1 0.1 0.1 100 5 -40
01.2 k - 12 k 1 0.1 0.1 0.1 100 5 -40
0 12 k - 120 k 10 0.1 0.1 0.1 100 5 -40
120 k - 1.2 M 100 00.2 + 3 μV 00.1 + 3 μV 0.1 + 3 μV 100 5 -40
1.2 M - 2 M 100 k 00.2 + 3 μV 00.1 + 3 μV 0.1 + 3 μV 100 0.5 -40
0 2 M - 10 M 100 k 00.4 + 3 μV 00.3 + 3 μV 0.2 + 3 μV 100 0.5 -40
10 M - 20 M 1 M 00.6 + 3 μV 00.5 + 3 μV 0.4 + 3 μV 150 0.5 -34
20 M - 30 M 1 M 10.5 + 15 μV 10.5 + 3 μV 0 1 + 3 μV 300 0.5 -34
Additional Operating Information:
dBm reference = 50
Range boundaries are at voltage points, dBm levels are approximate.
dBm = 10 log
Minimum output: 300
Frequency uncertainty:
Frequency resolution: 11,999 counts to 1.1999 MHz, 119 counts to 30 MHz.
Overload protection: A short circuit on the wideband output will not result in damage. After settling time, normal operation is
restored upon removal.
Frequency
Resolution
Hz Hz ± (% output + floor indicated) ±ppm/°C Seconds dB
Ω
Power
(
) ; 0.22361 V across 50 Ω = 1 mW or 0 dBm
1 mW
μV (-57 dBm)
±0.01 %
Amplitude Flatness, 1 kHz Reference
Voltage Range
1.1 mV 3 mV >3 mV
Temperature
Coefficient
Time To
Full
Accuracy
Harmonic
Distortion
1-28
Introduction and Specifications
General Specifications 1
1-18. General Specifications
Warm-Up Time: Twice the time since last warmed up, to a maximum of 30 minutes.
System installation: Rear output configuration and rack- mount kit available.
Standard interfaces: IEEE-488, RS-232, 5725A, 5205A or 5215A, 5220A, phase lock in (BNC), phase
reference out (BNC).
Temperature performance: Operating: 0 °C to 50 °C. Calibration: 15 °C to 35 °C. Storage: -40 °C to
75 °C; DC Zeros calibration required every 30 days.
Relative humidity: Operating: <80 % to 30 °C, <70 % to 40 °C, <40 % to 50 °C. Storage: <95 %, non-
condensing. A power stabilization period of four days may be required after extended storage at high
temperature and humidity.
Safety: Designed to comply with UL3111; EN61010; CSA C22.2 No. 1010; ANSI/ISA S82.01-1994
Guard isolation: 20 V
EMI/RFI: Designed to comply with FCC Rules Part 15, Subpart B, Class B; EN50081-1, EN50082-1
Electro Static Discharge: This instrument meets criteria C for ESD requirements per EN61326
Line Power: 47 to 63 Hz; ±10 % allowed about selectable nominal line voltage: 100 V, 110 V, 115 V,
120 V, 200 V, 220 V, 230 V, 240 V. Maximum power: 5700A/5720A, 300 VA; 5725A, 750 VA.
Size:
5700A/5720A: Height 17.8 cm (7 in), standard rack increment, plus 1.5 cm (0.6 in) for feet; Width 43.2 cm
(17 in), standard rack width; Depth 63.0 cm (24.8 in), overall; 57.8 cm (22.7 in), rack depth.
5725A: Height 13.3 cm, (5.25 in); Width and depth same as 5700A/5720A. Both units project 5.1 cm, (2 in)
from rack front.
Weight: 5700A/5720A: 27kg (62 lbs); 5725A: 32kg (70 lbs).
43.2 cm (17 in)
17.8 cm (7 in)
63 cm (24.8 in)
6.35 cm (2.5 in)
FOR CABLE
ACCESS
1-29
5725A
Instruction Manual
1-19. Auxiliary Amplifier Specifications
5205A (220V - 1100 V ac, 0 V - 1100 V dc)
For complete specifications, see the 5205A and 5220A Operators Manuals.
Overshoot: < 10 %
Distortion (bandwidth 10 Hz - 1 MHz):
10 Hz - 20 kHz
20 kHz - 50 kHz
50 kHz - 100 kHz
quency
Fre
(Hz)
0.07 %
0.2 %
0.25 %
90 Day Accuracy
at 23° ±5 °C
± (% output + % range)
Temperature Coefficient for
0°-18 °C and 28°-50 °C
± (ppm output + ppm range)/ °C
00 dc
010 - 40
040 - 20 k
20 k - 50 k
50 k - 100 k
0.05 + 0.005
0.15 + 0.005
0.04 + 0.004
0.08 + 0.006
00.1 + 0.01
5220A (AC Current, 180-day specifications):
Accuracy:
20 Hz - 1 kHz
1 kHz - 5 kHz
Temperature Coefficient (0° - 18 °C and 28° - 50 °C): (0.003 % + 100 μA)/°C
Distortion (bandwidth 300 kHz):
20 Hz - 1 kHz
1 kHz - 5 kHz
Note: 5700A/5720A combined with 5220A is not specified for inductive loads.
0.07% + 1 mA
(0.07% + 1mA) x frequency in kHz
0.1% + 1 mA
(0.1% + 1 mA) x frequency in kHz
15 + 3
45 + 3
15 + 3
50 + 10
70 + 20
1-30
Chapter 2
Installation
Title Page
2-1. Introduction
2-2. Unpacking and Inspection .................................................................... 2-3
2-3. Service Information .............................................................................. 2-5
2-4. Placement and Rack Mounting ............................................................. 2-5
2-5. Cooling Considerations......................................................................... 2-5
2-6. Connecting to the 5700A Calibrator ..................................................... 2-6
2-7. Selecting Line Voltage .......................................................................... 2-7
2-8. Accessing the Fuse ................................................................................ 2-8
2-9. Connecting to Line Power .................................................................... 2-9
........................................................................................... 2-3
2-1
5725A
Instruction Manual
2-2
Warning
The 5725A amplifier is capable of supplying lethal voltages. Do
not touch the 5700A output terminals. Read this section before
operating the 5725A.
2-1. Introduction
This section provides instructions for unpacking and installing the 5725A. Procedures for
line voltage selection, fuse replacement, and connection to line power and the 5700A
Calibrator are provided here. Read this section before operating the 5725A.
Instructions for connecting cables to a UUT (Unit Under Test) are in Section 4 of the
5700A/5720A Series II Operator Manual.
2-2. Unpacking and Inspection
The 5725A is shipped in a container that is specially designed to prevent damage during
shipping. Inspect the 5725A carefully for damage, and immediately report any damage to
the shipper. Instructions for inspection and claims are included in the shipping container.
Installation
Introduction 2
If you need to reship the 5725A, use the original container. If it is not available, you can
order a new container from Fluke by identifying the amplifier's model and serial number.
When you unpack the 5725A, check for all the standard equipment listed in Table 2-1.
Report any shortage to the place of purchase or to the nearest Technical Service Center. If
performance tests are required for your acceptance procedures, refer to Section 3 of the
5700A/5720A Series II Service Manual for instructions.
Line power cords available from Fluke are listed in Table 2-2 and illustrated in
Figure 2-1.
Table 2-1. Standard Equipment
Item Model or Part Number
Amplifier 5725A
Line Power Cord (See Table 2-2 and Figure 2-1)
Shielded 5700A/5725A Interface Cable 842901
5725A Getting Started Manual 1780175
5725A CD-ROM (contains Instruction Manual) 1780182
Spare 4A, 250V Fuse 216846
Certificate of Calibration (No Part Number)
2-3
5725A
Instruction Manual
Table 2-2. Line Power Cord Types Available from Fluke
TYPE VOLTAGE/CURRENT FLUKE OPTION NUMBER
North America 120V/15A LC-1
North America 240V/15A LC-2
Universal Euro 220V/16A LC-3
United Kingdom 240V/13A LC-4
Switzerland 220V/10A LC-5
Australia 240V/10A LC-6
South Africa 240V/5A LC-7
LC-1 LC-2 LC-3 LC-4
LC-5 LC-6 LC-7
Figure 2-1. Line Power Cords Available for Fluke Instruments
aq2f.eps
2-4
2-3. Service Information
Each 5725A Amplifier is warranted to the original purchaser for a period of one year
beginning on the date received. The warranty is located at the front of this manual.
Factory-authorized service and technical advice for the 5725A is available at Fluke
Service Centers. A complete list of service centers is available at www.fluke.com.
Warning
Servicing described in this manual is to be done by qualified
service personnel only. To avoid electrical shock, do not
service the 5725A unless you are qualified to do so.
The owner may choose to repair a 5725A using the troubleshooting information in
Section 7 to isolate a faulty module, then use the Module Exchange Program. Refer to the
Fluke catalog or contact a Service Center representative for the module exchange
procedure.
2-4. Placement and Rack Mounting
You can stack the 5725A on top of or below the 5700A Calibrator. (Choose the
configuration that provides the easiest access to the 5700A Calibrator controls.) Or, you
can mount the 5725A in a standard-width, 24-inch (61-cm) deep equipment rack. For
bench-top stacking, the 5725A is equipped with non-skid feet. To mount the 5725A in an
equipment rack, order the accessory 5725A Rack Mount Kit, Model Y5735. An
instruction sheet is packed with the kit.
Installation
Service Information 2
Caution
Use only the rack mount slides included in the Y5735 kit. Rack
mount slides intended for other instruments can block the side
ventilation holes on the 5725A and cause overheating.
2-5. Cooling Considerations
Caution
Damage caused by overheating may occur if the area around
the air intake is restricted, the intake air is too warm, or the fan
filter becomes clogged.
Accuracy
maintaining the coolest possible internal temperature. By observing the following rules
you can lengthen the life of the 5725A:
• The area around the fan filter must be at least 3 inches from nearby
• Exhaust perforations on the sides of the 5725A must be clear of obstructions. Most of
• Air entering the instrum
• Clean the fan filter every
and dependability of all internal parts of the 5725A are enhanced by
enclosures.
the heat exits from the side vents near the front.
ent must be room temperature. Make sure that exhaust from
another instrume
dusty
environm
nt is not directed into the fan inlet.
30 days, or more frequently
ent. (Instructions for cleaning the fan filter are in Section 6.)
walls or rack
if the 5725A is operated in a
2-5
5725A
Instruction Manual
2-6. Connecting to the 5700A Calibrator
Proceed as follows to connect the 5725A to the 5700A:
1. Turn the power off for both instruments and disconnect their line power cords.
2. Connect either end of the interface cable to the 5725A connector labeled 5700A.
Dress the cable only as Figure 2-2 shows. The figure shows how to dress the cable in
installation arrangements with the 5725A on top or bottom.
3. Connect the other end to th e 5700A connector labeled 5725A.
The 5700A/5725A interface cable provides all the digital and analog control signals for
the amplifier, and it provides conductors to route amplified voltage to the 5700A
OUTPUT binding posts.
5700A
5725A
5725A
AMPLIFIER
5700A
CALIBRATOR
5700A
CALIBRATOR
5725A
5725A
AMPLIFIER
Figure 2-2. Correct Way to Dress Interface Cable
5700A
aq3f.eps
2-6
Installation
Selecting Line Voltage 2
2-7. Selecting Line Voltage
The 5725A arrives from the factory configured for the line voltage normally appropriate
for the country of purchase, or as specified at the time of purchase. Check the line power
label on the rear panel of the 5725A to verify that the line voltage matches local line
power. Figure 2-3 shows the location of the line power label and switches, and the switch
settings for each line voltage.
The 5725A can be set to operate from eight different nominal line voltages; each voltage
setting has a voltage tolerance of ±10% and a frequency range of 47 to 63 Hz. The line
voltage switches are located on the bottom left side of the rear panel.
To change the line voltage setting, set the line voltage selection switches to the correct
setting shown in Figure 2-3.
CAUTION
FOR FIRE PROTECTION
REPLACE ONLY WITH A 250V FUSE
OF INDICATED RATING.
CHASSIS
GROUND
GROUNDING
WARNING
CONNECTOR IN POWER CORD
MUST BE CONNECTED TO
ENSURE PROTECTION FROM
ELECTRONIC SHOCK.
47-63 Hz
750VA MAX
!
FUSE
VOLTAGE
SELECTION
FUSE
S2 S3 S4
100V
110V
115V
!
F8A 250V
(FAST)
120V
S2 S3 S4
200V
220V
230V
!
F4A 250V
(FAST)
240V
CAUTION
FOR FIRE PROTECTION
REPLACE ONLY WITH A 250V FUSE
OF INDICATED RATING.
VOLTAGE
FUSE
SELECTION
S2 S3 S4
100V
!
110V
F8A 250V
(FAST)
115V
120V
S2 S3 S4
200V
!
220V
F4A 250V
(FAST)
230V
240V
S4S3S2
JOHN FLUKE MFG. CO., INC.
MADE IN U.S.A.
PATENTS PENDING
NO INTERNAL USER SERVICEABLE
PARTS REFER SERVICE TO
QUALIFIED SERVICE PERSONNEL
TO CLEAN FILTER
REMOVE FROM INSTRUMENT
AND FLUSH WITH WARM
SOAPY WATER
5700A CALIBRATOR
Figure 2-3. Line Power Label and Switch Location
CURRENT
OUTPUT
HI
11A MAX
20V PK
LO
MAX
CALIBRATION
ENABLE NORMAL
aq4f.eps
2-7
5725A
Instruction Manual
2-8. Accessing the Fuse
Caution
To prevent instrument damage, verify that the correct fuse is
installed for the line voltage setting. Acceptable fuse types are
Bussman type MTH or Littelfuse type 312 or equivalent, of the
appropriate amperage rating. Use only a 4A, 250V fast-blow
fuse when the line voltage selection switches are set in the
range 200-240V.
Note
A spare 4A, 250V fuse is shipped with the 5725A to ensure that one is
available for use on the 200-240V range.
The line power fuse is accessible on the rear panel. The fuse rating label to the right of
the fuse holder (labeled FUSE) shows the correct replacem
voltage setting. To check or replace the fuse, refer to Figure 2-4 and proceed as follows:
ent fuse rating for each line
1. Turn off the POWER switch and disconnect the line power cord from
ac line power.
2. Insert the blade of a standard screwdriver in the slot of the fuse holder labeled FUSE.
3. Turn the screwdriver counterclockwise until the cap and fuse pop free.
4. To reinstall the fuse, reverse this procedure.
JOHN FLUKE MFG. CO., INC.
MADE IN U.S.A.
PATENTS PENDING
NO INTERNAL USER SERVICEABLE
PARTS REFER SERVICE TO
QUALIFIED SERVICE PERSONNEL
TO CLEAN FILTER
REMOVE FROM INSTRUMENT
AND FLUSH WITH WARM
SOAPY WATER
5700A CALIBRATOR
CURRENT
OUTPUT
HI
11A MAX
20V PK
LO
MAX
CALIBRATION
ENABLE NORMAL
CHASSIS
GROUND
WARNING
GROUNDING
CONNECTOR IN POWER CORD
MUST BE CONNECTED TO
ENSURE PROTECTION FROM
ELECTRONIC SHOCK.
47-63 Hz
750VA MAX
!
FUSE
CAUTION
FOR FIRE PROTECTION
REPLACE ONLY WITH A 250V FUSE
OF INDICATED RATING.
VOLTAGE
FUSE
SELECTION
S2 S3 S4
100V
!
110V
F8A 250V
(FAST)
115V
120V
S2 S3 S4
200V
!
220V
F4A 250V
(FAST)
230V
240V
S4S3S2
2-8
Figure 2-4. Accessing the Fuse
aq5f.eps
Installation
Connecting to Line Power 2
2-9. Connecting to Line Power
Warning
To avoid shock hazard, connect the factory-supplied, threeconductor line power cord to a properly grounded power outlet.
Do not use a two-conductor adapter or extension cord; this will
break the protective ground connection.
After verifying that the line voltage selection switches are correctly set, verify that the
correct fuse is installed. Connect the 5725A to a properly grounded three-prong outlet.
2-9
5725A
Instruction Manual
2-10
Chapter 3
Operating Notes
Title Page
3-1. Introduction ........................................................................................... 3-3
3-2. Front Panel Features ............................................................................. 3-4
3-3. Rear Panel Features .............................................................................. 3-6
3-4. Turning on the 5725A Amplifier .......................................................... 3-8
3-5. Warm Up............................................................................................... 3-8
3-6. 5725A Operating Functions and Modes ............................................... 3-9
3-7. Standby ............................................................................................. 3-9
3-8. Voltage Standby ............................................................................... 3-10
3-9. Current Standby ................................................................................ 3-11
3-10. Voltage Operate ................................................................................ 3-12
3-11. Current Operate ................................................................................ 3-13
3-12. Conditions That Activate the 5725A .................................................... 3-14
3-1
5725A
Instruction Manual
3-2
3-1. Introduction
This section provides setup and operation information for the 5725A Amplifier. This
section begins with a reference for the 5725A front and rear panel features. Information
about setting up and powering up the 5725A follows. Please read this information before
operating the amplifier. Also contained in this section is a description of all 5725A
operating functions and modes. Because the amplifier operates under complete control of
the 5700A Calibrator, operating instructions such as how to call up a specific output
value are contained in Section 4 of the 5700A/5720A Series II Operator Manual.
Operating the 5725A in remote control is covered in Section 5 of the 5700A/5720A
Series II Operator Manual.
Operating Notes
Introduction 3
3-3
5725A
Instruction Manual
3-2. Front Panel Features
Front panel features are called out in Figure 3-1. Each front panel feature is described in
Table 3-1.
1
4
3
2
CURRENT
LO
HI
OUTPUT
11A
MAX
2OV
PK
MAX
8
VOLTAGE MODE
CURRENT MODE
5725A STANDBY
FAULT
OVERLOAD
CABLE OFF
6
POWER
5
7
aq6f.eps
Figure 3-1. Front Panel Features
3-4
Operating Notes
Table 3-1. Front Panel Features
Front Panel Features 3
CURRENT OUTPUT Binding Posts
The source of all amplified current if the 5725A is configured for front output. You can set the
5700A to source all unamplified as well as amplified current through these binding posts. The LO
binding post is isolated from ground when in the current function, and is open-circuited at other
times. Cable and connection recommendations are made in Section 4 of the 5700A/5720A
Series II Operator Manual.
5725A STANDBY Indicator
Lit whenever the 5725A is in any of three standby modes. This indicator is lit alone in standby
mode; it is lit at the same time as VOLTAGE MODE in voltage standby mode; and it is lit at the
same time as CURRENT MODE in current standby mode. (See "5725A Operating Functions
and Modes," further on in this section.)
CURRENT MODE Indicator
Lit when the 5725A is in current standby or current operate mode. In current standby mode, the
STANDBY indicator is also lit. (See "5725A Operating Functions and Modes," further on in this
section.)
VOLTAGE MODE Indicator
Lit when the 5725A is in voltage standby or voltage operate mode. In voltage standby mode, the
STANDBY indicator is also lit. (See "5725A Operating Functions and Modes," further on in this
section.)
POWER Switch
Turns the power on and off. The switch is a push-push type; the first push turns the power on
and locks the switch in, and the second push turns the power off and releases the switch.
CABLE OFF Indicator
Lit when the 5700A/5725A interface cable is not connected, or when the 5700A power is turned
off. This condition also lights the FAULT indicator.
OVERLOAD Indicator
Lights on entering current operate mode in overcompliance conditions (load not connected to the
proper binding posts, or load resistance too high). The OVERLOAD indicator also lights on
entering voltage operate mode if the load resistance is too low.
FAULT Indicator
Lit whenever any fault condition is detected. Normally, a fault code and message appears on the
5700A Control Display when this happens. The FAULT indicator also comes on with the CABLE
OFF indicator when the 5700A/5725A interface cable is not connected. In case of a FAULT
indication, check the 5700A/5725A interface cable connections, make sure the 5700A power is
on, and check that the load is appropriate and connected to the correct binding posts. Refer to
"Service Information" in Section 2, or to Section 7, Troubleshooting, in case of a FAULT
indication that appears to be a malfunction.
3-5
5725A
Instruction Manual
3-3. Rear Panel Features
Rear panel features are called out in Figure 3-2. Each rear panel feature is briefly
described in Table 3-2.
1
JOHN FLUKE MFG. CO., INC.
MADE IN U.S.A.
PATENTS PENDING
NO INTERNAL USER SERVICEABLE
PARTS REFER SERVICE TO
QUALIFIED SERVICE PERSONNEL
TO CLEAN FILTER
REMOVE FROM INSTRUMENT
AND FLUSH WITH WARM
SOAPY WATER
5700A CALIBRATOR
20V PK
CURRENT
OUTPUT
HI
11A MAX
MAX
LO
CALIBRATION
ENABLE NORMAL
CHASSIS
GROUND
GROUNDING
WARNING
CONNECTOR IN POWER CORD
MUST BE CONNECTED TO
ENSURE PROTECTION FROM
ELECTRONIC SHOCK.
47-63 Hz
750VA MAX
!
FUSE
CAUTION
FOR FIRE PROTECTION
REPLACE ONLY WITH A 250V FUSE
OF INDICATED RATING.
VOLTAGE
FUSE
SELECTION
S2 S3 S4
100V
!
110V
F8A 250V
(FAST)
115V
120V
S2 S3 S4
200V
!
220V
F4A 250V
(FAST)
230V
240V
S4S3S2
9
7
8
6
5
4
3
2
aq7f.eps
Figure 3-2. Rear Panel Features
3-6
Operating Notes
Table 3-2. Rear Panel Features
Rear Panel Features 3
CURRENT OUTPUT Binding Posts
The source of all amplified current if the 5725A is configured for rear output. You can set the
5700A to source all its unamplified as well as amplified current through these binding posts. The
LO binding post is isolated from ground when in the current function, and is open-circuited at
other times. Cable and connection recommendations are made in Section 4 of the 5700A/5720A
Series II Operator Manual.
CALIBRATION Switch
A slide switch that enables and disables writing to the nonvolatile memory that stores 5725A
calibration constants. Switching to ENABLE allows writing to the memory, and switching to
NORMAL protects data in memory from being overwritten. The switch must be in the ENABLE
position to store corrections generated during calibration. The switch is recessed to allow a
metrologist to cover it with a calibration seal to guarantee calibrator integrity.
5700A CALIBRATOR Connector
Provides the analog and digital interface to the 5700A Calibrator. After connecting to the 5700A,
you control the 5725A from the 5700A front panel or by sending remote commands to the
5700A. Refer to "Using an Auxiliary Amplifier" in Section 4, or for remote operation to Section 5,
of the 5700A/5720A Series II Operator Manual for details.
Fan Filter
Covers the air intake to keep dust and debris out of the instrument. The fan directs a constant
cooling air flow throughout the chassis.
Line Voltage/Fuse Rating Label
Shows the various settings of the line voltage switches, and the correct replacement fuse for
operating voltages of 110 (90 to 132) and 220 (180 to 264) volts ac. Refer to "Accessing the
Fuse" in Section 2 for the fuse replacement procedure.
Line Voltage Selection Switches
Select the operating line voltage. Refer to "Selecting Line Voltage" in Section 2 for instructions
on how to select operating line voltage.
Fuse Holder
The line power fuse. Refer to "Accessing the Fuse" in Section 2 for fuse rating information and
the fuse replacement procedure.
CHASSIS GROUND Connector
If the 5725A is the location of the ground reference point in a system, the CHASSIS GROUND
binding post can be used for connecting other instruments to earth ground. (The chassis is
connected to earth ground through the three-conductor line cord.)
Line Power Input
A grounded male three-prong connector that accepts the line power cord.
3-7
5725A
Instruction Manual
3-4. Turning on the 5725A Amplifier
Warning
To avoid electric shock, make sure the 5725A is safely
grounded as described in section 2.
Caution
Before turning the 5725A on, make sure that the line voltage
selection switches are set properly for your line voltage. Refer
to Figure 2-3 or the line voltage switch label and check the line
voltage setting now if you have not already done so.
When you turn on the 5725A, all six front panel indicators light briefly and the 5725A
undergoes a self test. If the self test fails, a fault message on the 5700A Control Display
identifies the failure, indicating that you should service the 5725A.
After the 5725A passes its self test, it transfers its calibration constants to the 5700A.
During the transfer, the BOOST indicator on the 5700A flashes. For the few seconds that
the BOOST indicator is flashing, the 5725A is not usable. After the transfer is complete,
the 5725A is in standby mode. (See "5725A Operating Functions and Modes" for more
information about standby mode.)
3-5. Warm Up
When you turn on a cold 5725A, warm it up for 30 minutes to allow the components
inside to stabilize. This ensures that the 5725A meets or exceeds the specifications listed
in Section 1.
If you turn off the 5725A after it has warmed up, allow it to warm up again for at least
twice the length of time it was turned off (up to a maximum of 30 minutes of warm-up).
For example, if the 5725A is turned off for 10 minutes, allow it to warm up again for at
least 20 minutes.
3-8
Operating Notes
5725A Operating Functions and Modes 3
3-6. 5725A Operating Functions and Modes
Warning
Both the 5700A and 5725A can produce fatal voltages. boosted
voltage operation produces high voltage at higher current
levels than normally available from the 5700A. during 5725A
voltage operation, the potential risk of injury or fatal accident is
greater than during unamplified 5700A voltage operation.
The 5725A has five normal modes of operation, including active output in its three output
functions: ac voltage, dc current, and ac current. The five normal operating modes are:
• Standby (also referred to as "dormant" on the schematics)
• Voltage Standby
• Current Standby
• Voltage Operate
• Current Operate
Each normal operating mode is described in the following paragraphs. For the meaning of
FAULT, OVERLOAD, or CABLE OFF indications, refer to Table 3-1.
3-7. Standby
NO OUTPUT
CURRENT
OUTPUT
HI
11A
MAX
LO
2OV
PK
MAX
Standby mode is when only the 5725A STANDBY indicator is lit. In standby mode, the
5725A is not supplying an output. However, the 5700A, depending on how it is set, can
be supplying up to 1100V or 2.2A. Standby occurs under any of the following
conditions:
• At power-up with no pending 5725A entry on the 5700A.
• When the 5725A is not selected in a 5700A setup menu as the amplifier for the
5700A output function in use, and the 5725A is not selected as the output location for
all 5700A current.
VOLTAGE MODE
CURRENT MODE
5725A STANDBY
FAULT
OVERLOAD
CABLE OFF
NO
OUTPUT
OUTPUT
HI
LO
HI
CURRENT
V A
Ω
AUX
SENSE
V A
Ω
GUARD
HI
LO
WIDEBAND
GROUND
Figure 3-3. Standby Mode Indicator
OPR
STBY
+/-
BOOST
OFF
EX SNS
EX GRD
87
9
5
4
1
6
2
3
0
•
W BND
BOOST
μ
m
k
M
aq8i.eps
3-9
5725A
Instruction Manual
3-8. Voltage Standby
Figure 3-4. Voltage Standby Mode
aq9i.eps
Voltage standby mode is when both VOLTAGE MODE and 5725A STANDBY
indicators are lit. In voltage standby mode, the 5725A is not supplying an output. Voltage
standby occurs if "5725A" is selected in a 5700A setup menu as the voltage amplifier,
and the next two conditions are true:
• An ac voltage 220V or above is showing on the 5700A Output Display
with the
STANDBY annunciator lit.
• The BOOST indicator on the 5700A is lit.
Note
If condition 1 is true, the BOOST indicator can be toggled on and off
by pressing the 5700A BOOST key. If the BOOST indicator is off,
the 5725A is in standby m
ode, not voltage standby.
3-10
3-9. Current Standby
Operating Notes
5725A Operating Functions and Modes 3
NO OUTPUT
CURRENT
OUTPUT
HI
LO
BOOST
LIT
OUTPUT
SENSE
V A
Ω
V A
AUX
Ω
GUARD
WIDEBAND
HI
LO
μ
GROUND
•
aq10i.eps
VOLTAGE MODE
CURRENT MODE
11A
MAX
2OV
PK
MAX
5725A STANDBY
FAULT
OVERLOAD
CABLE OFF
NO
OUTPUT
HI
LO
HI
CURRENT
Figure 3-5. Current Standby Mode
Current standby mode is when both CURRENT MODE and 5725A STANDBY
indicators are lit. In current standby mode, the 5725A is not supplying an output. Current
standby occurs under any of the following conditions:
• When the 5700A current output location is set to "5725A", and any
ac or dc current
level is showing on the 5700A Output Display with the STANDBY annunciator lit.
• If "5725A" is selected in a 5700A setup m
enu as the current amplifier, and any
of the
following conditions are true:
1. An ac or dc current 2.2A or above is showing on the 5700A Output Display with
the STANDBY annunciator lit.
2. Any
level of dc current is showing on the 5700A Output Display
with the
STANDBY annunciator lit, and the BOOST key on the 5700A is pressed so that
the BOOST indicator is lit.
3. An ac current 1A or above is showing on the 5700A Output Display with the
STANDBY annunciator lit, and the BOOST key on the 5700A is pressed so that
the BOOST indicator is lit.
4. The 5700A is ranged locked on the 11A range, and any dc current or an ac
current 1A or above is showing on the Output Display with the STANDBY
annunciator lit.
3-11
5725A
Instruction Manual
3-10. Voltage Operate
NO OUTPUT
CURRENT
OUTPUT
HI
LO
BOOST
LIT
VOLTAGE MODE
CURRENT MODE
11A
MAX
2OV
PK
MAX
5725A STANDBY
FAULT
OVERLOAD
CABLE OFF
VOLTAGE
OUTPUT
HERE
OUTPUT
HI
LO
HI
CURRENT
V A
Ω
AUX
SENSE
V A
Ω
GUARD
WIDEBAND
HI
LO
μ
GROUND
•
aq11i.eps
Figure 3-6. Voltage Operate Mode
Warning
Both the 5700A and 5725A can produce fatal voltages. boosted
voltage operation produces high voltage at higher current
levels than normally available from the 5700A. during voltage
operation, the potential risk of injury or fatal accident is greater
than during normal operation.
Voltage operate mode is when only the VOLTAGE MODE indicator is lit. In voltage
operate mode, amplified voltage output is available at the 5700A binding posts. Voltage
operate occurs if "5725A" is selected in a 5700A setup menu as the voltage amplifier, and
the next two conditions are true:
• An ac voltage 220V or above is showing on the 5700A Output Display
OPERATE annunciator lit.
• The BOOST indicator on the 5700A is lit.
Note
If condition 1 is true, the BOOST indicator can be toggled on and off
by pressing the 5700A BOOST key. If the BOOST indicator is off,
then the 5725A is in standby m
ode.
Note
Under certain settings of ac voltage, especially high voltage between
1 to 5 kHz, a whine from the 5725A is audible. This originates from
the output transformer, and is normal.
with the
3-12
Operating Notes
5725A Operating Functions and Modes 3
3-11. Current Operate
CURRENT
OUTPUT
HERE
OUTPUT
SENSE
Ω
V A
V A
AUX
Ω
GUARD
HI
LO
WIDEBAND
GROUND
HI
LO
CURRENT
OUTPUT
VOLTAGE MODE
CURRENT MODE
11A
MAX
2OV
PK
MAX
5725A STANDBY
FAULT
OVERLOAD
CABLE OFF
NO
OUTPUT
HI
LO
HI
CURRENT
Figure 3-7. Current Operate Mode
Note
An overcompliance fault occurs if a low-resistance load is not
connected to the enabled 5725A binding posts when entering
current operate mode.
•
BOOST
LIT
μ
aq12i.eps
Current operate mode is when only the CURRENT MODE indicator is lit. In current
operate mode, current output (either 5725A amplified current or redirected 5700A
current) is available at the 5725A binding posts. Current operate occurs under the
following conditions:
• When, on the 5700A, the current output location is set to "5725A", and any ac or dc
current level is showing on the 5700A Output Display with the OPERATE
annunciator lit.
• If "5725A" is selected in a 5700A setup menu as the current amplifier, and any of the
following conditions are true:
1. An ac or dc current 2.2A or above is showing on the 5700A Output Display with
the OPERATE annunciator lit.
2. Any level of dc current is showing on the 5700A Output Display with the
OPERATE annunciator lit, and the BOOST key on the 5700A is pressed so that
the BOOST indicator is lit.
3. An ac current 1A or above is showing on the 5700A Output Display with the
OPERATE annunciator lit, and the BOOST key on the 5700A is pressed so that
the BOOST indicator is lit.
4. The 5700A is ranged locked on the 11A range, and any dc current or an ac
current 1A or above is showing on the Output Display with the OPERATE
annunciator lit.
Note
Under certain settings of ac current, especially high current at
frequencies above 1 kHz, a whine from the 5725A is audible. This is
caused by a piezo effect in the current output transistors, and is
normal.
3-13
5725A
Instruction Manual
3-12. Conditions That Activate the 5725A
When the 5725A is connected to the 5700A, and is selected as the amplifier for the active
output function, it supplies an output under the conditions shown in the following list.
(These conditions are the same as VOLTAGE OPERATE and CURRENT OPERATE as
previously described.)
• Whenever current above 2.2A is selected
and the 5700A is set to operate. (Output
available at the 5725A binding posts.)
• Whenever ac voltage in the 220-1100V range is selected and the 5700A is set to
operate. Note that the 5725A takes over the 1100V ac range of the 5700A if the
5725A is selected as the voltage am
plifier in a setup me
nu. (Output available at the
5700A binding posts.)
• Whenever the 5700A BOOST key
is toggled
on while the 5700A output setting is in
the operating range of the 5725A, voltage or current. (Output location is 5725A for
current, 5700A for voltage.)
• If the "Range" softkey
is set to "LOCKED" while supplyi
ng a current greater than
2.2A, then the 5725A stays active if the 5700A output setting is adjusted down to 0A
dc, or down to 1A ac. (Output available at the 5725A binding posts.)
Regardless of the "BOOST AMP TYPES" setting in the 5700A setup m
enus, all
unamplified 5700A current is supplied through the 5725A binding posts when, on the
5700A, the current output location is set to "5725A"; the 5700A output is set to any ac or
dc current level; and the 5700A OPERATE annunciator is lit.
3-14
Chapter 4
Theory of Operation
Title Page
4-1. Introduction ........................................................................................... 4-3
4-2. Overall Functional Description ............................................................. 4-3
4-3. 1100V AC Range Functional Description ........................................ 4-5
4-4. 11A Range Functional Description .................................................. 4-6
4-5. Operation in the 11A DC Range .................................................. 4-7
4-6. Operation in the 11A AC Range .................................................. 4-7
4-7. Voltage and Current Standby Modes ............................................... 4-7
4-8. Voltage Standby ........................................................................... 4-7
4-9. Current Standby ........................................................................... 4-7
4-10. How the 5700A and 5725A Communicate ....................................... 4-8
4-11. Description of the Out-Guard Lines (5725A Side) ...................... 4-8
4-12. Description of the In-Guard Lines ............................................... 4-9
4-13. Functional Summaries by Assembly ................................................ 4-10
4-14. Detailed Circuit Description ................................................................. 4-11
4-15. Interconnect Assembly (A1) ............................................................. 4-11
4-16. Power Supply Assembly (A4) .......................................................... 4-12
4-17. High Voltage Supply Section ....................................................... 4-13
4-18. Switching Section ........................................................................ 4-14
4-19. Current-Limit Section .................................................................. 4-15
4-20. System Supply Section ................................................................. 4-15
4-21. Fan Supply Section ...................................................................... 4-16
4-22. Digital Assembly (A5) ..................................................................... 4-16
4-23. Microcomputer ............................................................................. 4-16
4-24. External RAM. ............................................................................. 4-16
4-25. External ROM .............................................................................. 4-16
4-26. EEROM ........................................................................................ 4-18
4-27. Data Latch .................................................................................... 4-18
4-28. Strobe Lines ................................................................................. 4-18
4-29. Led Driver .................................................................................... 4-18
4-30. Optoisolator Link ......................................................................... 4-18
4-1
5725A
Instruction Manual
4-31. Break-Detect Circuitry ................................................................. 4-18
4-32. Power Up and Reset Circuitry ...................................................... 4-19
4-33. Watchdog Timer........................................................................... 4-19
4-34. Current Amplifier Assembly (A2) .................................................... 4-19
4-35. Error Amplifier Section ................................................................ 4-21
4-36. Output Stage Section .................................................................... 4-22
4-37. Monitor Section ............................................................................ 4-22
4-38. Control and Switching Section..................................................... 4-23
4-39. Power Supply Section .................................................................. 4-23
4-40. High Voltage Amplifier (A3) ........................................................... 4-24
4-41. Input Amplifier ............................................................................ 4-24
4-42. Integrator ...................................................................................... 4-26
4-43. Window Comparator .................................................................... 4-26
4-44. Input Clamp .................................................................................. 4-26
4-45. Transconductance and Cascode Stage .......................................... 4-27
4-46. Midstage ....................................................................................... 4-27
4-47. Midstage -400V Filter .................................................................. 4-27
4-48. High Voltage Heat Sink Assemblies ............................................ 4-27
4-49. Autobias Current Source .............................................................. 4-28
4-50. Autobias Sense Circuit ................................................................. 4-28
4-51. High Voltage Amplifier Feedback ............................................... 4-29
4-52. Signal Transformers ..................................................................... 4-29
4-53. Temperature Monitoring .............................................................. 4-29
4-54. High Voltage Sense Assembly (A6) ................................................. 4-30
4-55. Sense Amplifier Section ............................................................... 4-32
4-56. Analog Monitor Section ............................................................... 4-34
4-57. Serial Interface/Guard Crossing Section ...................................... 4-35
4-58. Analog Input Switching Section .................................................. 4-35
4-59. Control Section ............................................................................ 4-36
4-60. AC Line Voltage Selection Section ............................................. 4-37
4-2
Theory of Operation
Circuit Description 4
4-1. Introduction
This section presents theory of operation in increasing level of detail. The 5725A
Amplifier is first broadly defined in an overall functional description and block diagram.
The overall functional description continues in more detail with functional descriptions
by function (ac V, dc I, ac I, and standby). The overall picture is completed with a
detailed discussion of how the 5700A and 5725A communicate. The largest part of this
section is devoted to detailed component-level circuit descriptions, grouped by assembly.
Warning
Lethal voltage (±500V) appears on the internal heat sink
assemblies, and at many other points inside the 5725A chassis.
Do not open the 5725A cover without referring to the access
procedures and warnings in section 6. Theory text in this
section is here strictly for the purpose of describing how
circuits work, and contains no access procedures.
4-2. Overall Functional Description
The 5725A provides three primary functions for the 5700A Calibrator:
• Extended frequency range for high ac voltage
• High-range dc current
• High-range ac current
The 5725A also has a secondary function of sourcing all 5700A current outputs (without
the 5700A Current guard) through its own binding posts, if so selected at the 5700A front
panel controls. Refer to Figure 4-1, the overall block diagram of the 5725A, for this
discussion. Each 5725A function is described briefly next.
• 1100V AC Function:
The 1100V ac function can output 220 to 1100V, 40 Hz to 30 kHz; and 220 to 750V,
30 kHz to 100 kHz. The 1100V ac function is implemented with a gain of -100
amplifier. Input for the ac voltage function comes from the 5700A Oscillator,
spanning the range of 2.2 to 11V. The 5725A returns an oscillator sense voltage of
precisely -1/100 of the output voltage to the 5700A. Voltage outputs go through the
5725A/5700A interconnect cable to either the 5700A front or rear panel OUTPUT
binding posts.
4-3
5725A
Instruction Manual
4-4
Figure 4-1. 5725A Overall Block Diagram
• 11A DC Function:
Theory of Operation
Circuit Description 4
The 11A dc function is im
plemented with
a transconductance (voltage in/current out)
amplifier with a gain of -5. If the 5700A outputs -2V into the 5725A, the 5725A
output is 10A. (This is transparent to the user.) The output range is 0 to 11A. The
5725A delivers am
plified current to either th
e front or rear panel binding posts of the
5725A, depending on an internal hardware setup. Reconfiguration requires removing
the covers, and is described in Section 6.
• 11A AC Function
The 11A ac function is sim
ilar to the 11A dc function. The frequency
to 10 kHz. The output range is 1 to 11A rms. As in the dc current function, all
outputs from the 5725A either go through the front or rear panel of the 5725A. Input
to the 5725A com
es from the 5700A Oscillator assembly.
4-3. 1100V AC Range Functional Description
The 5700A Oscillator assembly generates the driving ac voltage, then sends it to the
5725A Power Amplifier for amplification. The 5725A returns an attenuated feedback
voltage for output correction. The final output voltage is kept accurate by the high
voltage sense amplifier and a real-time, software-controlled feedback loop within the
5700A, incorporating a 5700A ac/dc thermal rms converter. The 5700A Oscillator, DAC
(digital-to-analog converter), and ac/dc thermal rms converter work together with the
5725A Power Amplifier and high voltage attenuator circuits to produce the desired
output.
Active assemblies in the 5725A ac voltage function are as follows:
range is 40 Hz
• In the 5700A: CPU, DAC, Oscillator, Oscilla
tor Control, High-Resolution Oscillator,
Switch Matrix, Motherboard, Rear Panel assemblies.
• In the 5725A: CPU, High Voltage Amplifier, High Voltage Sense, Signal
Transform
er, Power Supply, Digital, and Interconnect assem
blies.
When an ac voltage in the 220 to 1100V range is selected, the 5700A calls the 5725A
plifier and leaves its own high voltage amplifier dormant. The 5725A takes over the
am
1100V ac range automatically. The 5725A produces ac voltage in the following
sequence:
1. The 5700A sets the Oscillator assembly to the proper frequency and am
5700A sets the initial am
Oscillator am
plifier assembly, yielding an Oscillator output accuracy
2. Next, the 5725A Power Am
plitude using an 8-bit resistive hy
plifier amplifies this signal by
brid dac located on the
-100 and returns an
plitude. The
of about 0.5%.
accurately attenuated signal to the 5700A.
3. The 5700A therm
al sensor and adc (analog-to-digital converter) monitoring system
fine tune the Oscillator amplitude. The DAC assembly output is switched directly
the Oscillator assem
bly, controlling the dac output am
plitude. AC voltage calibration
constants stored in the 5725A determine the 5700A DAC voltage setting.
to
4-5
5725A
Instruction Manual
The 5700A/5725A system uses the following method for ac amplitude control:
1. An rms thermal sensor alternately measur
ac signal, and a known calibrated dc signal.
2. The output of the therm
the sensor each tim
al sensor is measured by the adc, allowing settling tim
e its input is changed. The ac signal is adjusted until the therma
sensor output is the same for both signals. Thus, the dc voltage at the output of the
al sensor is not important, but differe
therm
input is switched between the ac variable and dc reference are important.
To ensure safe, reliable operation, the High Voltage Am
following sequence:
1. The 5700A Oscillator is set to the 22V range
High Voltage Amplifier on line BOOST IN.
2. Then the output of the High Voltage Am
voltage step-up transformer (one of three).
4-4. 11A Range Functional Description
The 5725A Current Amplifier is a transconductance amplifier that has a compliance
voltage of 3.0V rms for the ac current function and 4.0V for the dc current function. The
transconductance amplifier has a gain of -5 (e.g., 1V in gives -5A out). Either the 5700A
2V range for dc operation, or the Oscillator for ac operation, drives the transconductance
amplifier. Input voltage to the transconductance amplifier comes in on BOOST IN (for ac
current) or B-FEEDBACK (for dc current) and enters the High Voltage Sense assembly.
From there it is routed to the error amplifier on the Current assembly whenever the
5725A is in the current function. The B-FEEDBACK line returns the current calibration
amplifier output to OSC SENSE HI during ac current operation.
es two signals: an unknown but adjustable
e for
nces in the dc voltage when the sensor
plifier is turned on in the
and its output is channeled to the 5725A
ier is connected to the appropriate high
plif
l
The following assemblies are active in the 5725A current function:
• In the 5700A: CPU, DAC, Oscillator, Sw
assem
blies. (Plus the Oscillator assembly
itch Matrix, Motherboard, Rear Panel
in the ac current function.)
• In the 5725A: CPU, Current, High Voltage Sense, Digital, and Power Supply
.
4-6
4-5. Operation in the 11A DC Range
For the dc current function, the 5700A is configured for the dc 2.2V range. The 5700A
2V dc range drives an error amplifier with an input impedance of 40 kΩ. The gain of this
amplifier is determined by this 40 kΩ resistor with a 4 kΩ feedback resistor, and the
value of the precision shunt. The 5725A uses a 0.02Ω shunt for the 11A function. There
is no feedback to the 5700A.
The 5725A monitors the error amplifier output voltage using the 16-channel multiplexer.
One channel of the multiplexer, ICOMPL M, is scanned every 30 milliseconds or faster,
with its output compared to -2V from the DAC. If the peak error amplifier output is more
negative than the dac voltage, MONCOMP goes LOW and is read by bit 6 of port 5 of
U507, the CPU. This indicates an overload condition, and lights the OVERLOAD LED.
If a later scan shows the same result, the CPU trips the Current Amplifier into standby
and reports this condition to the 5700A.
A soft-start from standby to operate transitions reduces sudden current changes. This
allows the 5725A to drive inductive loads such as power meters and clamp-on type
current probes.
4-6. Operation in the 11A AC Range
Theory of Operation
Circuit Description 4
For ac current operation, input to the 5725A comes from the 5700A Oscillator. The
5700A Oscillator is configured for the 2.2V ac range, with sensing back to the 5700A
Oscillator coming from the current shunt through the calibration amplifier circuit (on the
Current Assembly).
4-7. Voltage and Current Standby Modes
When a change in output function is selected, the 5725A goes through voltage or current
standby mode before connecting the output to the 5725A binding posts, or to the 5700A.
Voltage or current standby allows for local sensing within the 5725A, and for
establishment of a known input condition in current and ac voltage.
4-8. Voltage Standby
In voltage standby, the 5700A binding posts are completely disconnected from the rest of
the instrument circuitry, and the 5725A high voltage output and sense lines (B-OUT HI
and B-SENSE HI) are disconnected from the 5725A/5700A connector. The High Voltage
Amplifier remains powered from the high voltage supply, but its input is grounded by
pulling CLAMPD, and its output (MV OUT) is disconnected from the output
transformers. Analog monitor circuitry continues to check the voltage and current on the
high voltage supplies as well as the heat sink temperatures and cable integrity. It prevents
the 5725A from switching to operate if a fault is present.
4-9. Current Standby
In current standby, the binding posts are disconnected from the instrument circuitry, but
all 5725A/5700A connections are made as in the operate mode. In dc current standby, the
5700A DAC supplies a voltage that corresponds to the dc current selected. In ac current
standby, 5725A relay settings are identical to those for dc current standby. The 5700A
Oscillator supplies an ac voltage level that corresponds to the selected output current and
frequency.
4-7
5725A
Instruction Manual
4-10. How the 5700A and 5725A Communicate
The 5725A and 5700A maintain all analog and digital communication over an external
cable connected to subminiature D-type connectors on the back of each instrument. All
in-guard (analog) signals, except B-VGRD, connect to relays that isolate the 5725A and
5700A whenever the 5725A is not in use.
Digital communication occurs over five out-guard (digital) 5700A lines, B-SCT, B-SCR,
B+5V, B+5VCOM, and B-CINT*. The B+5V and B+5VCOM lines power the 5725A
guard crossing and allow the 5725A to detect when the cable is disconnected. Lines BSCT and B-SCR provide serial communication of data over an RS-232 type line.
Optoisolators on the 5725A maintain the integrity of the guard. Line B-CINT* is a
hardwire loop that allows the 5700A to detect a cable off or 5725A power off condition.
4-11. Description of the Out-Guard Lines (5725A S
The following list describes the five 5725A out-guard lines:
• B-RCV (Serial Communication Receive)
Receives serial data from the 5700A; connects to the B-SCT line of the 5700A.
• B-XMIT (Serial Communication Transmit)
Transmits serial data to the 5700A; connects to the B-SCR line of the 5700A.
• B+5V
5700A out-guard supply that powers optoisolators and 5725A CABLEOFF relay.
• B+5VCOM
5700A out-guard supply common for above.
• B-CINT* (Boost Cable Interlock)
Hardwire "loop around system" on the 5725A that is polled at least every 100 ms by
the 5700A to determine if the 5700A/5725A cable is connected and if the 5725A is
turned on. Returns a low to the 5700A if above is true. A pull-up resistor on the
5700A leaves this line high if the interconnect cable is open or if the 5725A is turned
off.
ide)
4-8
4-12. Description of the In-Guard Lines
The following list describes the 11 5725A in-guard lines:
• B-RCL
High-quality analog line from the 5725A which carries critical signals to be
easured by
m
diagnostics. During calibration, these signals are ICAL (output of the current
calibration amplifier), HVSENSE (DC output of the sense amplifier during dc gain ac
characterization), AC/AC (buffered output of the 5725A thermal rms sensor that does
frequency characterization).
• B-OUT HI
High voltage output from the 5725A step-up transformers, to be routed to either the
5700A front or rear panel terminals.
• B-SENSE HI
High voltage sense line from the 5700A output terminals. This signal is then
attenuated -100:1 by the High Voltage Sense assembly.
• BOOST IN
the 5700A adc during either 5725A calibration or 5725A self
Theory of Operation
Circuit Description 4
During normal 5725A ac operation, carries the 5700A DAC outputs, which in turn
drives either the High Voltage Amplifier or Current Amplifier. During 5725A
calibration, BOOST IN drives the High Voltage Sense assem
with up to -260V
bly
from the 5700A Power Amplifier.
• B-CURRENT
Analog line that carries the current high output from the 5700A. When the user sets
the current output location to "5725A" in a 5700A menu, this signal is routed to the
5725A binding posts. Under this operating condition, all 5700A/5725A current
ranges are available from the same binding posts. Line B-CURRENT carries up to
2.2A in normal operation. During current calibration, this line carries 1.3A to
easure the value of the 0.02Ω
m
5725A current shunt.
• B-IRTN
Current return for B-CURRENT; carries up to 2.2A. Line B-IRTN eventually ties to
the same node as SCOM on the 5700A.
• B-IGRD
Current guard voltage from the 5700A; enables internal guarding within the 5725A
only
.
• B-VGRD
5700A guard. Enables discrete guarding/shielding within the 5725A.
• B-PACOM
System common from the 5700A. Once inside the 5725A, it becomes VCOM,
HVCOM, DCOM, and KCOM. B-PACOM is the current return for signals from the
5700A, including source current for driving the 5725A in the ac voltage function.
Current output from the 5700A, when "5725A" is selected as the current output
location, returns via B-IRTN.
• B-SENSE LO
High quality ground from the 5700A that is the reference point for the 5700A DAC
and Oscillator assemblies.
4-9
5725A
Instruction Manual
Inside the 5725A, B-SENSE LO is buffered by the 5725A, with the equivalent
voltage called MCOM.
•
B-FEEDBACK
During ac voltage operation, B-FEEDBACK is the output of the High Voltage Sense
bly; this signal represents B-SENSE HI divided by
assem
ac/dc therm
al sensor. During low-frequency
path for the -260V dc from
ac voltage calibration, this is the sense
the 5700A Power Am
plifier.
-100, and drives the 5700A
During ac current operation, B-FEEDBACK is the output of the current calibration
plifier. It represents the output current divided by
am
-5 and drives the 5700A
Oscillator feedback.
During dc current operation, voltage from
on B-FEEDBACK.
If B-FEEDBACK is out of tolerance during 5725A ac voltage or current operation
but no other faults are reported, the 5700A sends a message to the 5725A asking for a
sequenced shutdown into standby
Display
. The 5725A FAULT indicator lights. A faulty
, and displays a fault m
connection could cause this problem.
4-13. Functional Summaries by Assembly
For an overview of all the assemblies in the 5725A and the functions contained on each,
refer to Figure 4-1, the overall block diagram, and the following list:
• Interconnect Assembly
• Connectors and traces to link other assemblies and fan
• High voltage transform
• Power Supply Assembly
• Rectifiers for high voltage supplies
• Filters for high voltage supplies
• High voltage current-lim
• High voltage supply-monitoring circuitry
• Rectifiers for system
• Filters for sy
• Regulators for sy
• Rectifiers for fan supply
• Filter for fan supply
stem
(A1):
er secondary switching circuitry
(A4):
it circuitry
supplies
supplies
stem
supplies
e 5700A 2V dc range is fed to the 5725A
th
essage on its Control
5700A/5725A interface
4-10
• Digital Assem
bly
(A5)
• LED front panel status annunciators
• CPU, RAM, ROM, EEROM, watchdog timer, logic
• Current Am
plifier Assembly
(A2):
• Transconductance amplifier
• Current shunt
• Heat sink and current power devices
• 5700A current routing circuits
• Filters for high current supply
• Rectifier bridge for high current supply
• Regulators for low current supply
• Current heat sink tem
perature m
onitor
• High Voltage Power Amplifier Assembly (A3)
• Power amplifier
• Harness to heat sink and its high voltage power devices
• Connections to the output transformers
• High voltage heat sink tem
perature monitoring circuitry
Theory of Operation
Circuit Description 4
• High Voltage Sense Assembly
(A6):
• High voltage sense (attenuator) and calibration circuits
• 5725A input and output switching relay
• Analog m
• Subm
onitor, an 8-bit dac, latch for m
iniature D-ty
pe connector to the 5700A
• 5700A current routing circuits
• Guard crossing
• AC line power selection circuitry
• AC line inrush current lim
iting circuitry
4-14. Detailed Circuit Description
Detailed circuit descriptions for each pca (printed circuit assembly) are provided next.
Individual block diagrams are provided for the Current Amplifier (A2), High Voltage
Amplifier (A3), High Voltage Sense (A6), and Digital (A5) assemblies. You may also
find it helpful to refer to the schematic diagrams (Section 9) while reading theory for
each assembly.
4-15. Interconnect Assembly (A1)
The Interconnect assembly (A1) links the other five assemblies in the 5725A. The
interconnect assembly contains the following parts:
• Connectors and traces to interconnect the other assem
three 32-pin DIN connectors on the Interconnect pca which connect the Power
Supply
Am
the High Voltage Sense assem
Interconnect assem
to the Interconnect assem
voltage transformers.
assembly (A4), High Voltage Amplifier assembly
plifier assembly (A2). A 64-pin DIN connector links the Interconnect assembly
bly
bly to the Digital assembly (A5). Other cable assem
bly go to the fan, High Voltage assembly
s, relay
drivers
ux, latch for dac
blies and the fan. There are
(A3), and Current
(A6). A 34-pin ribbon cable connector links the
blies attached
output, and high
to
• High voltage transform
relay
s (K013, K014, and K015) select one of three ac voltage output transforme
fourth relay
the low-frequency
(K001) is a high voltage armature ty
transforme
The circuit board has four lay
er secondary-switching circuitry.
pe that connects the secondaries of
r in either a series or parallel fashion.
ers. Most connections are done on the inner two layers. One
Three high voltage reed
outer layer is an earth ground plane; the other outer layer is tied to the signal VCOM.
rs. A
4-11
5725A
Instruction Manual
4-16. Power Supply Assembly (A4)
The Power Supply assembly (A4) provides regulated system supplies for all 5725A
assemblies except as noted below, as well as unregulated fan supply and high voltage
supplies for the High Voltage Amplifier. The assembly also includes microprocessorcontrolled switching and an independent current-limit circuit.
Note
Other power supplies are contained on the Current Amplifier assembly
±
(A2). The A2 assembly includes a high-current supply and a local
20V
supply.
The Power Supply assembly has four sections: high voltage supply, switching, current
limit, and system supply section. Each section is first briefly described, then described in
detail.
• High Voltage Supply
The high voltage supply
the additional capability
50V dc for troubleshooting.
or at ±
Section
section consists of a simple unregulated power supply
of being run at ±400V dc for normal instrume
• Switching Section
The switching section behaves like an electronic DPST switch, which by
of the m
icroprocessor or the current-lim
it section, shuts down the high voltage
supplies. Microprocessor control alone can turn on the high voltage supplies in
norm
al operation. At the board level, manua
enable stand-alone turn on of the Power Supply
plifier assembly
Am
(A3).
l control of the switch is possible to
assembly
(A4) and the High Voltage
• Current-Limit Section
The current-lim
excessive current is drawn by
supplies fail. This section of the Power Supply
a pair of com
stem Supply
• Sy
The sy
com
stem supply section contains vari
prised of five linear regulators. In addition, the system supply
it section shuts down the high voltage supply in a latching m
the High Voltage Amplifier or if the ±
parators, and a system supply m
assembly
onitor.
consists of a pair of shunts,
15V or +5V
Section
ous regulated power supplies, and is
section contains an
unregulated supply for the fan.
with
nt operation,
comma
nd
ode if
4-12
4-17. High Voltage Supply Section
The high voltage supply allows normal operation from a pair of nominal 400V dc
supplies, or troubleshooting operation in a reduced voltage mode with a pair of nominal
50V dc supplies. Switching between normal and reduced-voltage operation is done by
removing the plug from J301 and inserting it into J303. See Section 7 for the procedure to
do this. (Plug P301 is wired with both 400V and 50V transformer taps so that the 400V
taps are connected in the circuit when P301 is plugged into J301, and the 50V taps are
connected in the circuit when P301 is plugged into J303.)
Two sets of high voltage rectifiers, CR301 through CR304 and CR310 through CR313,
form bridge rectifiers for the positive and negative supplies, respectively. The output
from these bridges is filtered by C301/C321 and C320/C322. The capacitor pairs are
configured in series to obtain the necessary working voltage. Bleeder resistors R303,
R314, R315, and R 308 discharge C301/C321 when power is removed and form a
voltage divider that equalizes the voltage across halves of C301. Resistors R335, R337,
R336, and R339 do the same function for C302/C322.
Warning
Do not rely on the power supply LEDs as an indication of the
presence of high voltage. Always use a voltmeter to check for
high voltage between TP307 and TP301, and between TP307
and TP304.
Theory of Operation
Circuit Description 4
Components CR317 and CR318 are high intensity red LEDs that provide visual
indication of the presence of high voltage. These LEDs have high luminosity at low
current levels. They are located in series with the bleeders for the positive and negative
supplies, using about 1 mA of current for bias. Under average lighting conditions, these
LEDs are visibly lit with as little as 40V on C301/C321 and C320/C322. Zeners VR306
and VR307 are normally off, as their zener voltages are greater than the forward voltage
of the LEDs. However, should an LED fail, these zeners carry enough current to allow
the bleeder resistors to function.
Fuses F301 and F302 protect the transformer against overload in case the 400V supplies
are shorted. Without these internal fuses, a short-circuit would cause excessive power
dissipation in the power transformer, even though ac line current would be insufficient to
blow the main fuse. Table 4-1 lists data for fuses F301 and F302, and the other internal
fuses in the 5725A.
Caution
For safety, replace internal fuses only with fuses of the rating
and type specified in Table 4-1.
Surge arrestor E302 fires if the secondary voltage of the +400V supply exceeds 600V.
This should only occur if the 5725A is plugged into an ac line voltage of 200V or more
when it is set to 100-120V. E302 would then draw enough current to blow the main fuse,
thereby protecting the 5725A.
Table 4-1. Internal Fuse Data
REF DES. ASSEMBLY RATING TYPE
F301 Power Supply (A4) 2A, 600V Littelfuse BLS or equivalent
F302 Power Supply (A4) 2A, 600V Littelfuse BLS or equivalent
F201 Current Amplifier (A2) 20A, 32V Bussman AGC or equivalent
F202 Current Amplifier (A2) 20A, 32V Bussman AGC or equivalent
4-13
5725A
Instruction Manual
4-18. Switching Section
MOSFETs Q301/Q317 and Q302/Q318 (each in parallel) are series-switch elements for
the +400V supply. Similarly, Q312/Q319 and Q313/Q320 are series-switch elements for
the -400V supply. Resistor pairs R301/R302 and R342/R343 equalize the voltage across
the transistors in their "off" state. Series transistors guarantee operation within the
MOSFET 500V absolute rating.
The MOSFET switches are controlled by the signal at TP305. When this point is at +5V,
the series connected base-emitter junctions of Q305/Q307 and Q304/Q306 are zero
biased. In this condition, only leakage current flows through Q305/Q307 and
Q304/Q306, which is insufficient to develop enough source-gate voltage to turn on
Q301/Q317, Q302/Q318, Q312/Q319, or Q313/Q320. When TP305 is taken low, the
series base-emitter junctions are now forward biased sufficiently so that the Q305/Q307
and Q304/Q306 pairs conduct with about 0.5 mA collector current. This current flows
through the source-gate resistor and zener diode bias networks of Q301/Q317,
Q302/Q318, Q312/Q319, and Q313/Q320. The zener diodes limit the source-gate voltage
to near 15V, which is enough to turn on the MOSFETs completely without exceeding
their source-gate voltage ratings.
Transistors Q303/Q321, Q311/Q323, Q315/Q322, and Q316/Q324 are emitter followers
that prevent Q305 and Q307 from experiencing excessive collector-emitter voltages in
their "off" state. The networks of resistors, capacitors, and diodes formed by
R344/C305/CR305, R327/C304/CR316 and R345/C306/CR309 are included to slow
supply turn-on to prevent a transient current-limiting condition, while still allowing rapid
supply turn-off.
Resistors R310/R311/R306 provide a divided voltage for low-level monitoring of the
+400V supply by the analog monitor on the High Voltage Sense assembly (A6).
Resistors R332/R346/R347 do the same for the -400V supply. Diodes CR314, CR315,
CR319, and CR320 prevent damage to the series-switches from inductive kickback
during shutdown.
Control over the potential at TP305 is controlled in one of the two following ways:
1. In normal operation (P301 plugged onto the E301 header where the label SYS
appears, pins 1 and 2), the microprocessor strobes the control data HVSUPPLY* into
U302 by pulsing HVSTROBE. This action occurs in parallel with writing
HVSUPPLY* information into a latch on the High Voltage Sense assembly (A6), but
there the sense of the HVSTROBE line is inverted.
Transistor Q304 provides correct polarity to the clock of U302. At any time, the
supply can be switched off (i.e., TP305 brought to +5V) independent of the processor
by the current-limit circuitry or by SW301 pulling the "set" line of U302 high
(TP306).
2. To turn on a Power Supply assembly (A4) by itself for troubleshooting, you can plug
P301 onto the E302 header where the label MAN appears (pins 2 and 3). This allows
momentary-contact pushbutton switch SW302 to generate a strobe signal for U302,
turning the supplies on. You turn the supplies off by pressing switch SW301. You
may wish to troubleshoot in the low-voltage mode by plugging the high voltage
secondary plug into J303. Section 7 contains the procedures to do this.
4-14
4-19. Current-Limit Section
Resistors R313 and R329 are current shunts for the high voltage supplies. These are
connected in series with the bridge rectifiers, with the common point between the shunts
being the high voltage supply common, HVCOM. The voltage developed across the
+400V shunt is negative; the voltage across the -400V shunt is positive.
The shunt voltages, +400V IMON and -400V IMON, in addition to being monitored by
comparators in the current-limit section, are routed via the Interconnect assembly (A1) to
the High Voltage Sense assembly (A6), where they are scanned by the analog monitor,
and to the High Voltage Amplifier assembly (A3) to control the autobias circuitry. The
negative current monitor signal is clamped by CR307 and filtered by R328 and C308
before being directly compared to 0.36V by U301B. The positive current monitor is more
complicated because of its negative value. To stay within the common-mode operating
range of U301A, the shunt signal is first summed with a reference voltage via the
R319/R318 network, after which it is clamped by CR306 and filtered by C308. The
comparator switching level is 0.18V. The summing network scales the shunt signal for
equal supply trip currents.
The outputs of U301A and U301B are open collector, which allows them to be wireOR'ed with the open drain output of Q309. The output of this logic drives Q308, resetting
the high voltage supply switches and signaling the processor via HVCLR. Transistor
Q310 monitors the presence of the ±15V supplies. If either of these supplies fail, the high
voltage supplies are switched off.
Theory of Operation
Circuit Description 4
4-20. System Supply Section
The digital/relay power supply tap (+5V) is routed via J350 through RT350 and bridge
rectifier CR351. A positive temperature-coefficient thermistor protects the instrument
from the secondary supply short circuits. This prevents them from thermally stressing the
power transformer. Three-terminal regulator U350 regulates the digital/relay supply with
1% initial tolerance and about 2% accuracy over temperature. Capacitor C350 filters the
input of U350; C351 filters the output.
The +5V digital supply powers both logic and relays. The power for each routes away
from the +5V regulator separately, via lines +5V and +5VK. This prevents relay drive
currents from causing drops in the logic supply voltage.
Because the ±20V supplies draw little current, they can share power transformer
secondary windings with the ±15V supply with little efficiency lost. This center-tapped
winding is brought to the Power Supply assembly via J350, where each half of the
winding is protected from short circuits by a thermistor. Bridge rectifier CR355, as well
as filter capacitors C353 and C356 again serve both supplies. The center tap of this
transformer winding forms VCOM, to which PACOM and HVCOM are tied to provide a
common reference for the instrument.
An accurate +15V supply is obtained by using U351. Regulator U352 regulates the -15V
supply.
An accurate +20V supply is obtained by regulating with U353, a 5V regulator, but
referencing it to the accurate +15V supply. VR351 forces U353 to be forward biased as
the +15V supply comes into regulation. This avoids powering up the +20V supply
through CR359 (at the improper voltage), reverse biasing U353.
A discrete regulator makes the negative -20V supply accurate. U354 is an error amplifier
that forces the junction of R352 and R350 to be 0V. In doing so, the -20V supply is
forced to be the inverse of the +20V supply within the matching of R350 and R352.
Transistor Q350 provides a pass element for the negative regulator; VR352 provides level
shifting so that the drive required from U354 is within its output swing range.
4-15
5725A
Instruction Manual
4-21. Fan Supply Section
4-22. Digital Assembly (A5)
The fan supply uses the same transformer secondary windings as the ±15 and ±20V
supplies. Its own full-wave bridge rectifier diodes create a supply voltage of +25V.
Transistor Q351 is operated near saturation, and provides the measurement point to tell
the CPU whether the fan is running. The output of Q351 is sent to the analog multiplexer
on line -FAN to accomplish this.
From a software standpoint, digital circuitry functions as a subset of the 5700A in-guard
CPU. Digital circuitry resides on three assemblies within the 5725A: the Digital assembly
(A5), the High Voltage Sense assembly (A6), and the Current Amplifier assembly (A2).
All the 5725A hardware, including digital, is in-guard, except for the guard crossing and
the CABLEOFF detection circuit.
Figure 4-2 is a block diagram of the Digital assembly. The Digital assembly contains
most of the digital circuitry, including the following:
• Microcomputer (Hitachi 6303Y CMOS)
• External RAM (CMOS static)
• External ROM
• EEROM (2Kb X 8)
• Break-detect circuitry
• Power up and reset circuitry
• Watchdog timer circuitry
• Front panel LEDs
• LED decoder and driver
The High Voltage Sense assembly (A6) contains the optoisolator link (guard crossing) to
the 5700A Main CPU and the CABLEOFF circuit.
The Current Amplifier assembly (A2) contains the interface to the digital bus (two
latches and three relay drivers) and a relay driver chip.
4-23. Microcomputer
The 6303Y CMOS microcomputer is configured for Mode 1 operation, with external
RAM and external ROM. Port 3 provides a common data bus (D00-D07), while port 1
and bits 0 through 5 of port 4 provide the address bus (A0-A13). Bits 6 and 7 of port 4
are address lines A14 and A15.
24. External RAM.
4-
External RAM is enabled whenever A15 is high, A14 is low (hex 8000-BFFF), and either
RD* or WR* is true. Reading and writing is controlled by bit 2 of port 7.
25. External ROM
4-
The external ROM (U515) is enabled via ROMSEL* whenever A15 and A14 are high
(hex C000-FFFF). Bit 0 of Port 7 (RD*) is OUTPUT ENABLE*.
4-16
Theory of Operation
Circuit Description 4
Figure 4-2. Digital Assembly Block Diagram
aq19f.eps
4-17
5725A
Instruction Manual
4-26. EEROM
4-27. Data Latch
A 2Kb X 8 EEROM (U512) stores 5725A calibration constants plus the date and
temperature of calibration. If the rear panel CALIBRATION switch is in the NORMAL
position, the EEROM is software write disabled. The 6303Y reads the CALIBRATION
switch via bit 1 of port 5 and enables the EEROM when the switch is in the ENABLE
position. The EEROM is selected when A15 and A14 are low, A13 is high (2000 through
3FFF), and either RD* or WR* is TRUE. Writing is controlled by bit 2 of port 7 and the
RESET* line.
The 5725A does not automatically format its own EEROM. The 5725A informs the
5700A Calibrator if a problem has been encountered at power-up. The 5700A assumes
responsibility for formatting the 5725A EEROM.
The Data Latch (U510) is enabled via LATCHSEL when three conditions are met:
address bit A15 is 0, A14 is 1 (hex 4000-7FFF), and WR* is 0 (true). Data Latch U510 (a
74HCT373) latches information on the external data bus (D0-D7) and sends this
information to the LED latch (U501), Current Amplifier assembly (A2), and the High
Voltage Sense assembly (A6).
4-28. Strobe Lines
The Current Amplifier (A2) and High Voltage Sense (A6) assemblies tie to the Data
Latch external data bus output with latching relay drivers and/or latches. Information is
strobed into the respective relay drivers/latches by the state of any of the seven strobe
lines. The seven strobe lines (STROBE 1-5,21,22) and a clear line (CLR), all asserted
high, are buffered (U503) outputs on port 6. An additional strobe line called
HVSTROBE, for use by the High Voltage Sense and Power Supply assemblies, is created
from STROBE 2 combined with STROBE 2 ENABLE* and HVSUPPLY*.
Line HVSUPPLY* is generated on the High Voltage Sense assembly. The strobe rate
varies from 50 ms for STROBE 2 to over 100 ms for the other strobe lines. The CLR line
opens all relays except K202.
4-29. Led Driver
Front panel LEDs are driven by U501, a 74HCT373 latch, which is capable of sinking 35
mA of LED operating current. An output LOW turns an LED on. The LED driver is
selected by bit 7 of port 5, LEDSEL.
30. Optoisolator Link
4-
An optoisolator circuit links the two-channel guard crossing. This guard crossing circuit
and the related 5725A/5700A interconnection reside on the High Voltage Sense assembly
(A6). Serial communication to and from this guard crossing uses the RECEIVE and
TRANSMIT lines, respectively.
4-18
When the 5725A is not being used, all cable inputs into the 5700A are tied to the 5700A
guard to shunt noise currents away.
4-31. Break-Detect Circuitry
The 6303Y divides the 4.9152-MHz crystal frequency by four to create the 1.2288-MHz
ECLK. This signal serves as the clock for the 74HC4020 counter (U506), which is
configured as a divide-by-16384. The RECEIVE line is usually high, except for the brief
interval when characters are being transmitted. As long as the low state is less than 13.34
ms, RECEIVE holds the CLR of the 74HC4020 TRUE. However, if communication
between the 5725A Amplifier and the 5700A Calibrator fails, the 5700A attempts to reset
the 5725A by sending a break (holding RECEIVE low for greater than 26.7 ms). This
action causes the 74HC4020 counter output (BREAK) to go high. Signal BREAK is
NOR'ed with CABLEOFF from the High Voltage Sense assembly (A6); either signal
causes a NON-MASKABLE INTERRUPT to the 6303Y. The 5700A also uses BREAK
to reset the 5725A.
4-32. Power Up and Reset Circuitry
Reset and glitch-detection circuitry primarily consists of U508, a TL7705A. This chip
detects if the power supply falls below 4.5V, if a reset input from a momentary contact
switch occurs, or if there is an output from the watchdog timer. Any combination of these
conditions resets the board via RESET* for 130 ms.
4-33. Watchdog Timer
Watchdog circuitry contains a 4538 Dual Monostable Multivibrator. The first
multivibrator (U509A) is configured as a 300 ms retriggerable one-shot that can fire a
second 3 ms one-shot (U509B). Control line STROBE 2 of the 6303 (bit 1, port 6)
retriggers the first one-shot every 50 ms and refreshes the high voltage relay driver. If
STROBE 2 is stuck high or low during operation, the first one-shot is no longer
retriggered, and its output transitions low. The second one-shot, configured to trigger on
a falling edge, now sends a pulse via RESIN* to the TL7705A reset IC U508. This action
forces the reset circuit to pull a hard reset on the 6303Y for 130 ms.
Theory of Operation
Circuit Description 4
The first trigger to the 4538 occurs when the 7705A RESET* line makes a transition
from low to high. During normal operation, STROBE 2 prevents another reset by
retriggering the first one-shot well before the 300 ms timeout. The watchdog fires only if
the CPU is executing erroneous code which does not activate STROBE 2.
4-34. Current Amplifier Assembly (A2)
The Current Amplifier assembly enables the 5725A to extend the current output range of
the 5700A Calibrator to ±11A dc or 11A ac. The 5700A drives the Current Amplifier
assembly input through the 5725A interface cable. There are no user input terminals.
Output current is available at binding posts on the 5725A front or rear panel. Selection of
front or rear 5725A binding posts is done by unplugging one cable and plugging in
another cable on the Current Amplifier assembly inside the 5725A chassis. Additionally,
relays on the Current Amplifier assembly can route the 5700A current source to the
5725A output terminals, if so selected at the 5700A front panel (or by remote command).
The Current Amplifier assembly has five distinct sections: the error amplifier, output,
control, monitor, and power supply. Each section is first briefly described, then described
in detail in the following paragraphs. Refer to Figure 4-3, a block diagram of the Current
Amplifier assembly, to see the interrelationship of the following function blocks.
4-19
5725A
Instruction Manual
4-20
Figure 4-3. Current Amplifier Assembly Block Diagram
aq20f.eps
Theory of Operation
Circuit Description 4
• Error Amplifier Section
The error amplifier section contains three differential amplifiers and a precision high-
current shunt resistor. Two differential amplifiers set the gain and uncorrected
frequency response of the current amplifier. The remaining differential amplifier is
used during the internal portion of 5700A/5725A calibration and during ac current
operation.
• Output Section
The output section contains several power transistors, a heat sink, two operational
amplifiers, a current buffer amplifier, two current sensing resistors and related
components. The output stage is driven by the error amplifier section, converting a
±3V signal into a ±15A signal. The output section is powered by floating supplies
that are referenced to the ICOM current common. The output stage is designed to
drive inductive loads.
• Monitor Section
The monitor section contains several op amps and comparators, and a thermistor. A
temperature monitor circuit observes the temperature of the voltage output
transistors. Excessive output compliance voltage is detected by the drive monitor
circuit. Both monitor circuits send scaled voltages to a multiplexed comparator on the
High Voltage Sense assembly (A6), where abnormal operating conditions are
detected.
• Control Section
The control section contains nine relays, a latched relay driver, several transistors,
and a quad comparator. The relays and transistors switch the Current Amplifier into
ac current and dc current operating states, a standby state, and several self calibration
and diagnostics states during which 5725A operation is monitored and characterized
by measurement circuitry and software residing in the 5700A.
• Power Supply Section
The power supply section contains two bipolar power supplies. Regulated ±20V
supplies and unregulated ±12V supplies are referenced to ICOM and power only the
output section. The error amplifier section and control section are powered from the
±15V and +5V 5725A system supplies.
35. Error Amplifier Section
4-
Refer to page 1 of the Current Amplifier schematic. Components U201, Z201, R235,
C230, and Q211 make up the "outer loop error amplifier," a differential amplifier with
high common-mode rejection ratio. The outer loop error amplifier controls a first-order
feedback loop that determines the dc accuracy and uncorrected ac frequency response of
the current amplifier. Q211 shuts off the outer loop error amplifier during standby and,
through modulation of its channel resistance by R255 and C210, yields a soft-start
transition into the operate modes.
Components U202, R232, R241, R251, R252, R234, C213, and Q213 comprise the inner
loop error amplifier. The inner loop error amplifier works with the outer loop amplifier in
a second-order feedback loop that significantly diminishes the effects of output stage
non-linearities. Q213 reduces the inner loop gain during standby.
Refer to page 2 of the Current Amplifier schematic. Resistor R272 is a specially
constructed 0.02Ω shunt resistor that senses the Current Amplifier output. U208 and
Z203 comprise a gain of ten differential amplifier called the calibration amplifier (Cal
Amp). The calibration amplifier scales the voltage dropped across R272, creating a signal
4-21
5725A
Instruction Manual
4-36. Output Stage Section
(ICAL, TP208) with the same amplitude and polarity as the current amplifier input voltage.
The calibration amplifier output is measured by circuitry within the 5700A during
calibration of the 5725A current amplifier. The calibration amplifier output is fed back to
the 5700A Oscillator during ac current operation.
The feedback signal from the precision shunt is applied to both the inner and outer loop
error amplifiers (ISENSE HI, ISENSE LO , pages 1 and 2). The error amplifier section
drives the output stage (TP204) so that the voltage across R272 is one-tenth of the
Current Amplifier input voltage (VINI). Thus, the Current Amplifier is a
transconductance amplifier: output current is proportional to input voltage. This
transconductance is -5A/V.
Refer to page 1 of the Current Amplifier schematic. Components U203, R203, R204, and
R209 convert the bipolar ground-referenced output signal from the error amplifier section
into two unipolar supply-referenced waveforms at the inputs to U204A and U204B. IC
U203 also isolates the output stage, which is referenced to a floating common (ICOM),
from the rest of the circuitry, which is referenced to circuit common (VCOM). The
operation of the positive and negative output halves are similar. Only the positive output
section is described below.
In response to a positive polarity error amplifier output (TP204), the current through
R209 increases. This same current flows into pin 2 of U203, causing the voltage drop
across R203 to increase. The voltage across R203 is applied to the positive input of
U204A. U204A drives Q203, Q205, and Q207 until the voltage at the emitter of Q207 is
identical to the voltage at the non-inverting input of U204A. Test point TP204 is a test
input for the output stage when in standby mode. The resulting output stage current can
be monitored at TP208 with a scaling of 200 mV/A.
The quiescent operating point of the output devices is fixed by the bias current of U203
and current source CR205 at about 1A. There is no output stage bias adjustment.
Capacitor C235 and resistors R256 through R260 provide a tertiary feedback path that
guarantees stability when the 5725A is driving the specified inductive loads.
4-37. Monitor Section
Refer to page 1 of the Current Amplifier schematic. Components U211C and D, U210C,
RT203, CR207, and associated resistors and capacitors make up the temperaturemonitoring circuit. Heat sink temperatures above approximately 85°C signal the
ITEMPM fault condition.
Components U207, R280 through 284, and C234 generate a negative voltage at TP207
(DRIVE MONITOR) that remains less than 3.1V in magnitude when the output
compliance voltage is within the linear operating range of the output stage. The output
compliance voltage is not measured by the drive monitor circuit; an overcompliance
condition is inferred from excessive error amplifier output.
4-22
4-38. Control and Switching Section
Refer to page 2 of the Current Amplifier schematic. Relays K201 through 209, Q214
through 216, and U209 through 210 configure the Current Amplifier circuitry for the
following six modes:
• Current Standby
Current Amplifier input is active through K201. Current Amplifier output is
disconnected from instrument output terminals but is routed through the sense path
through K202.
• Operate1
Input is connected to BOOST IN and MCOM. Output is connected to front or rear
output terminals. FET switches Q211 and Q213 are off, enabling the error amplifier
circuitry. Operate1 is the active mode for delivering up to 11A (ac or dc) to a UUT.
• Operate2
The Current Amplifier is configured as in standby mode, except K201 is off. 5700A
current source is routed to the 5725A current output terminals through K205.
Operate2 is the active mode for delivering 2.2A or less to the 5725A terminals unless
the 5725A 11A current range has been explicitly enabled from the 5700A front panel
or by remote command.
Theory of Operation
Circuit Description 4
• Calibrate1 (Shunt Calibration)
Input is shorted. Error amplifiers are disabled with Q211 and Q213. Output is routed
directly to current return path through K207, bypassing sense circuits. 5700A current
source is routed through K206 to the 5725A current sense path. Procedures
performed during Calibrate1 determine the value of R272. This is one of the factors
in the dc gain and the only factor in the ac gain of the Current Amplifier.
• Calibrate2 (Offset Calibration)
The amplifier is configured as in Calibrate1, except with its output routed by K208 to
the 5700A. Procedures performed during Calibrate2 determine the dc offset of the
Current Amplifier.
• Calibrate3 (Gain Calibration)
Input is connected to BOOST IN, B-FEEDBACK, and MCOM as in Operate1, but
Output is routed through the current sense path through K202. Output is not
connected to output terminals. Procedures performed during Calibrate3 determine the
gain of the error amplifier, the other factor in the dc gain of the Current Amplifier.
4-39. Power Supply Section
Refer to page 3 of the Current Amplifier schematic. The unregulated, high-current supply
is made from K208 through 209, F201 through 202, CR206, and C218 through C221.
The regulated ±20V supplies are composed of RT201 through 202, U205, U206, CR212
through 215, C222, C223, and associated components. Thermistors RT201 and RT202
are PTC thermistors for current limiting and transformer protection.
4-23
5725A
Instruction Manual
4-40. High Voltage Amplifier (A3)
The High Voltage Amplifier assembly, operating with the step-up signal transformers,
constitutes an amplifier with an inverting gain of 100. It amplifies 2.2V to 11V signals
from the 5700A Oscillator and returns 220V to 1100V to the 5700A where they go to the
5700A OUTPUT HI/OUTPUT LO binding posts. The signals to and from the 5700A
come through the High Voltage Sense assembly (A6) where they are switched.
The High Voltage Amplifier assembly consists of an input amplifier, integrator, window
comparator, input clamp, transconductance and cascode stage, midstage, midstage -400V
filter, high voltage heat sink assemblies, autobias current source, autobias sense circuit,
high voltage amplifier feedback, and temperature monitoring circuits.
The High Voltage Amplifier drives the primary winding of the appropriate signal
transformer depending on the frequency of operation. Signal transformers are interfaced
to the High Voltage Amplifier via connector J604. Relays that select signal transformers
are mentioned under the heading "Signal Transformers" further on.
The High Voltage Amplifier assembly uses the ±400V supplies from the Power Supply
assembly. Lethal voltage appears on the heat sink assemblies. Do not open the 5725A
cover without referring to the access procedures and warnings in Section 6.
Figure 4-4 is a block diagram of the High Voltage Amplifier assembly. Refer to the block
diagram or the schematic to better understand theory of operation.
4-41. Input Amplifier
The input amplifier, U602, is an op amp whose input comes from HV IN on J653 through
R623 and R621. HV IN is the 2.2V to 11V ac signal generated by the 5700A and routed
through the High Voltage Sense assembly. The input amplifier has a high-frequency gain
of 5.5, but because feedback resistor R622 is ac-coupled through C615, the gain is much
higher at low frequencies. The inverting input of U602 is buffered with Q601. The
nominal output of the input amplifier, LVAMP TP602, is about 6V dc.
4-24
Theory of Operation
Circuit Description 4
Figure 4-4. High Voltage Amplifier Assembly Block Diagram
aq22f.eps
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Instruction Manual
4-42. Integrator
4-43. Window Comparator
Op amp U601A is configured as an integrator to reduce the output offset of the input
amplifier circuit. This integrator senses the output voltage of the amplifier (MVOUT)
through R604 and R605 and forces it to be zero with respect to HVCOMM.
Comparators U604A and U604B form a window comparator that monitors the output of
the input amplifier, U602. The window is set to about +2.2V to +9V by R626, VR602,
and R636. If the output of U602 exceeds the window limits, the appropriate comparator
turns on the clamp, Q604, shorting the input to ground. The comparator also pulls control
line CLAMPS high via U604D, where the comparator routes to the Digital Assembly
(A5) through the Interconnect assembly (A1). Comparator U604D is a level shifter to
translate the window comparator output to a TTL level.
Exceeding the limits of the window comparator is an indication that the loop is in an
abnormal condition when the instrument is in the ac voltage standby or ac voltage operate
states. In current standby or current operate states, the comparator causes CLAMPS to be
asserted, which turns off the +400V and -400V supplies.
4-44. Input Clamp
A FET clamp, Q604, is turned on until the output of U602 returns to the region within the
window. When this occurs, the comparator turns off Q603. To avoid a large transient at
the output of the High Voltage Amplifier assembly (A6), the clamp must be turned off
slowly. Resistor R637 and C618 slow the clamp drive signal to accomplish this. Though
Q604 can be turned off slowly by removing its gate drive slowly, it clamps
asymmetrically in the transition region. The body of the FET is held at -7.5V. This keeps
the FET from turning on at the negative peaks of the input waveform. The asymmetrical
clamping appears as a dc shift in the waveform, which can cause the transformer to
saturate. To alleviate this problem, a second clamp is placed in parallel with Q604.
This second clamp is the photoresistor portion of the optical isolator, U605. It has a
considerably higher on resistance than Q604, so the two are used together. When the
clamp is to be turned off, Q603 is turned off and the voltage on C618 begins its transition
from nearly +15V to -15V. At +15V, Q604 is turned on but because Q605 is also on,
shunting current from the input of U605, the photoresistor is in the high impedance state.
When the voltage on C618 reaches about +9V, Q605 turns off and the optoisolator is
turned on, putting the photoresistor into its low resistance state. This has little effect on
the input signal because the photoresistor is a higher impedance than the FET. As the
control voltage approaches zero, Q604 turns off and the input is clamped only by the
photoresistor. As the control voltage continues toward -15V, the photoresistor makes the
transition to its off, or high impedance state. The photoresistor clamps symmetrically,
eliminating the dc transient on the input. A similar transition takes place when light turns
on the clamp but it happens much faster, as the turn-on transition is controlled by the time
constant R631*C618 which is about an order of magnitude faster than the R637*C618
turn-off time constant.
4-26
The microprocessor on the Digital assembly can also pull the clamp via control line
CLAMPD, which is latched into a driver on the High Voltage Sense assembly (A6). Line
CLAMPD is asserted during a sequenced turn on, power down of the High Voltage
Amplifier assembly (A3), or during a transition to another frequency range. Comparator
U604C level shifts CLAMPD and provides an OR function with the window comparator
output.
4-45. Transconductance and Cascode Stage
The output voltage of the input amplifier U602, LVAMP, is transformed into a current by
Q602. The nominal current is about 8.5 mA. This implies that the nominal output voltage
of the input amplifier is about 6V; 15V - (.0085 * 1000) - .6 = 5.9V.
The current is passed through a cascode FET Q661, which can stand off the voltage
required, about 400V. A zener diode similar to VR656 protects most of the power
MOSFETs from damage to their gate oxide layer by excessive gate voltage
(approximately ±20V). A gate resistor similar to R675 suppresses high frequency
oscillations.
4-46. Midstage
The current from Q661 generates a voltage of about 8.5V across R698. The ac voltage
gain from TP602, the LVAMP output, to R698 is unity. Transistor Q666 mirrors the
current into the midstage with an ac gain of 5. The dc midstage current is about 28 mA.
The midstage current passes through two cascode FETs, Q662 and Q665, to bias resistor
R674. Transistor Q660, VR658, and R678 form a 21 mA current source that, along with
R674 establishes the midstage bias current at about 28 mA. FET Q653 is a current source
from the +400V supply controlled by the auto-bias circuitry. The bias for Q654 and Q662
comes from the high voltage heat sink assemblies and is maintained about halfway
between the output voltage and the +400V supply or -400V supply, respectively. The
bias for Q665 comes from zener VR665, FET Q667, and its associated parts, which form
a 3 mA current source to bias the zener.
Theory of Operation
Circuit Description 4
Zener VR661 provides some additional protection for Q665 and Q666. Capacitor C660
and R612 provide the dominant pole to stabilize the midstage amplifier. Gain-bandwidth
is set to about 7 MHz.
4-47. Midstage -400V Filter
FET Q670 is a filter to reduce the 120 Hz and output signal ripple on the -400V supply.
Zener VR663, acting as a normal diode, clamps the gate of Q670 at the positive peak of
the ripple on the -400V supply. As soon as the -400V supply moves away from the
positive peak, the gate voltage is heavily filtered by R695 and C663. The zener action of
VR663 and VR664 prevents Q670 from being damaged by excessive gate voltage as the 400V supply is turned on.
48. High Voltage Heat Sink Assemblies
4-
The output power MOSFET devices are mounted in pairs on the four high voltage heat
sink assemblies. Each pair is driven with the same gate voltage. To ensure they equally
divide the current, the MOSFETS are matched for gate-source voltage at 0.5A and have
3.9Ω source resistors. The push-pull output stage consists of Q655 and Q656 on the N-
channel heat sink assembly #2 and Q663 and Q664 on the P-channel heat sink assembly
#2. Their gates are driven with the voltage on R674. Resistors R670 through R673 sense
the output current, while Q658 and Q659 limit the current to about 2.4A. Diodes CR652
and CR654 help to reduce the amount of stored charge in the power MOSFETs that must
be driven when they are turned on and off.
The power MOSFETs on the #1 heat sink assemblies are driven cascode to share the
voltage drop between the output (MVOUT) and their respective 400V supply. This also
balances their power dissipation with the #2 heat sink assemblies. Their gates are driven
from the voltage divider R654 and R661 or R684 and R692. Capacitors C654 and C661
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5725A
Instruction Manual
4-49. Autobias Current Source
compensate for the capacitance seen at the gates of the power MOSFETs on the #1 heat
sink assemblies. Their sources establish the voltage on the gates of the cascode FETs in
the midstage, Q654 and Q662.
The power MOSFETs are in the TO3 package and are mounted to the heat sinks using a
heat conductive pad (electrically conductive as well) to minimize thermal resistance to
the heat sink. This means that the heat sinks can have ±400V on them during normal
operation. Do not open the 5725A cover without referring to the access procedures and
warnings in Section 6.
Lower voltage supplies of about ±50V are available on the board to replace the ±400V
supplies during test and troubleshooting. How to power up in the reduced-voltage
troubleshooting mode is described in Section 7.
The four heat sink assemblies are attached to the High Voltage Amplifier assembly (A3)
via connectors P661-664. A thermistor is stud mounted to the P-channel heat sink
assembly #2 and attaches to the High Voltage Amplifier Assembly through J603. The
temperature monitoring circuit, described further on, uses this thermistor.
FET Q653 is a current mirror that provides a dc current to bias the midstage. FET Q654
is a cascode stage to share the voltage and power. Since the loop forces the dc output of
the amplifier back to zero if the midstage current is increased, the effect of increasing the
midstage current is to increase the voltage drop across R674. Midstage current is
increased until the gates of the output devices (connected to either end of R674) are
driven just hard enough to establish the desired idle current in the output stage.
The current that Q653 mirrors comes from Q657, which is driven by BIAS from the
Autobias Sense Circuit. FET Q657 stands off the high voltage to the +400V supply and
makes the autobias circuit less sensitive to its ripple.
4-50. Autobias Sense Circuit
The autobias sense circuit senses the +400V IM from the Power Supply assembly (A4).
Signal +400V IM is a voltage developed across a R313 in the low side of the +400V
supply, which provides a voltage proportional to the current in the 400V supply. If the
High Voltage Amplifier were operating Class B, the +400V IM waveform would be half
sines for a sinusoidal output current waveform.
The autobias sense circuit forces the average current in the +400V supply to be greater
than the average of a half sine to produce Class A-B operation. This results in Class A
operation for small output currents and for high output currents, a +400V IM waveform
that looks like a half sine at the peak but is more rounded at the base. The autobias sense
circuit does this by measuring the average of +400V IM and comparing it to the peak of
+400V IM / pi (the average that would have been obtained for Class B operation), plus an
offset.
Op amp U606A and C621 are configured as a peak detector. Resistors R647 and R648
divide the peak by pi. Resistor R643 and the 15V supply provide the offset: (15V * 10K)
/ (4.3M * 0.39) = 90 mA.
These signals are summed into integrator U601B. The integrator is an error amplifier that
drives the autobias current source circuitry, via BIAS, to achieve the desired relationship
between the peak and average values of the current delivered by the +400V supply.
4-28
Op amp U606B senses the -400V supply and forces the autobias to the minimum bias
condition when the ±400V supplies are turned off. Transistor Q606 forces the minimum
bias condition when the window comparator is activated.
4-51. High Voltage Amplifier Feedback
Feedback for the High Voltage Amplifier is provided by R606, R607, and R608 from the
output signal MVOUT. This means that the high voltage signal transformers are driven
open loop by the High Voltage Amplifier. Feedback for amplitude leveling is provided
on the High Voltage Sense Assembly (A6).
The turns ratio of the hf transformer is less than the other transformers. Resistor R608
compensates for the difference in turns ratio so the overall gain of the High Voltage
Amplifier, plus the signal transformers, is -100 independent of frequency range. Resistor
R608 is switched in by K601 only in standby mode and in hf operation.
4-52. Signal Transformers
Three transformers cover the four frequency ranges as shown in Table 4-2. The lf
transformer is a C-core. The mf and hf transformers are toroids. All three signal
transformers are located in the transformer box on the left side of the instrument when
viewed from the front.
Theory of Operation
Circuit Description 4
Table 4-2. Signal Transformer Usage
High Voltage
Frequency Range
40 Hz to 120 Hz LF (Series) 1:5.5 40 to 200V 220 to 1100V
120 Hz to 3.4 kHz LF (Parallel) 1:5.5 40 to 200V 220 to 1100V
3.4 kHz to 30 kHz MF 1:5.5 40 to 200V 220 to 1100V
30 kHz to 100 kHz H F 1:4.5 49 to 167V 220 to 750V
Transformer Turns Ratio
Amplifier Output
(MVOUT)
High Voltage
Transformer
Output
Four control lines: HFPD, MFPD, LFPD, and VLFPD, control the frequency ranges. The
control lines are generated on the High Voltage Sense assembly. These lines control
relays K601 to K604, which direct the High Voltage Amplifier output to the primary of
the appropriate transformer and switch in feedback resistor R608 to compensate for the hf
transformer turns ratio. Relay K604 switches the primary windings of the lf transformer
into a series connected configuration for 40 to 120 Hz operation, and into a parallel
connected configuration for 120 Hz to 3.5 kHz operation.
Relays on the Interconnect assembly (A1) switch the secondary transformer windings.
These Interconnect relays are driven by the same control lines as the High Voltage
Amplifier assembly. These lines originate from latch/driver U157 on the High Voltage
Sense assembly (A6).
4-53. Temperature M
onitoring
The temperature monitoring circuit estimates the junction temperature of the power
MOSFETs by measuring the temperature of one of the high voltage heat sinks and adding
a calculated temperature rise from heat sink to junction, based on the current in the
+400V supply.
The heat sink temperature is sensed with a stud-mounted thermistor mounted into the Pchannel heat sink #2 via connector J603. Its negative temperature coefficient is linearized
4-29
5725A
Instruction Manual
4-54. High Voltage Sense Assembly (A6)
to approximately 33Ω/°C by R615. Op amp U603A provides a reference voltage of about
-0.77V. This reference voltage is applied to the circuit containing summing amplifier
U603B, R611, and the linearized thermistor. The output of U603B is signal HV TEMP
M, equal to 10 mV/°C.
A voltage proportional to the temperature rise from the heat sink to the junction of the
transistor is added to HV TEMP M through R610. This is done via +400V IM from the
Power Supply assembly. Resistor R610 is selected to properly scale this contribution to
the 10 mV/°C output of U603B. Capacitor C610 provides averaging for the ripple on the
current-sensing resistor, and CR604 prevents C610, an electrolytic capacitor from being
reverse charged.
In addition to ac voltage sensing for which it is named, the High Voltage Sense assembly
provides four major functions for the 5725A. These additional functions are the
following:
• Analog m
onitoring of the 5725A status
• Interface with the 5700A controller
• Switching input signals from the 5700A
• AC Line Power switching
Because it perform
s all the above functions, the High Voltage Sense assembly plays a
primary role in controlling the instrument, attaining ac voltage specifications, performing
5725A calibration, and maintaining instrument safety.
The High Voltage Sense assembly has the following six sections: sense amplifier, analog
monitor, serial interface/guard crossing, analog input switching, control, and mains
switching. Each section is first briefly described, then described in detail. For reference,
see Figure 4-5, the block diagram for the High Voltage Sense assembly.
• Sense Am
The sense am
active attenuator, a buffer am
the 5700A ground reference, and a precision true rm
plifier Section
plifier section consists of a precision ac am
plifier that isolates the 5725A high quality ground from
plifier configured as an
s converter circuit for 5725A
calibration. Together, these circuits accurately attenuate the output of the 5725A in ac
voltage function to drive the 5700A Oscillator control circuitry
. The sense am
plifier
section is essentially a gain-determining feedback element of a loop whose forward
path consists of the 5700A Oscillator and the High Voltage Am
plifier assembly
(A3).
• Analog Monitor Section
The analog m
16-channel m
representing critical param
involving high voltage and/or current. Each input can be com
its set by the dac under microprocessor control. The comparator gives simp
lim
go/no go decisions, which are then acted on in a m
onitor section is comprised of a bipolar output dac, a comp
ultiplexer. The inputs to the mu
ltiplexer are scaled voltages
eters in the other 5725A assemblies, particularly
pared to programme
ore sophisticated way by
arator, and a
those
d
le
the
software. An additional function of the analog monitor section is to provide access to
the B-RCL line used by the 5700A during 5725A calibration.
4-30
Theory of Operation
Circuit Description 4
Figure 4-5. High Voltage Sense Assembly Block Diagram
aq21f.eps
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5725A
Instruction Manual
• Serial Interface/Guard Crossing Section
The serial interface/guard crossing section consists of an RS-232 interface integrated
circuit that provides the hardware for 5700A/5725A communication within the
5725A. Two optoisolators provide the serial guard crossing to the Digital assembly
(A5), and two more provide integrity checks for the interface. A relay remotely
powered by the 5700A provides a software independent path to guarantee 5725A
shutdown if the 5700A/5725A cable is disconnected.
• Analog Input Switching Section
The analog input switching section consists of a bank of relays that route ac and dc
voltages and dc currents from the 5700A to various functional blocks inside the
5725A. Assemblies that receive inputs from the Analog Input Switching Section are
the High Voltage Amplifier assembly (A3); the Current Amplifier assembly (A2);
and the sense amplifier section of the High Voltage Sense assembly.
• Control Section
The control section is implemented with a bank of four latches connected to the
microprocessor data bus. A pair of latches with their integral drivers control relays, a
pair of latches control the 16-channel multiplexer and the bipolar output dac in the
analog monitor section.
• AC Line Voltage Switching Section
The ac line voltage switching section is independent of the other five sections of the
High Voltage Sense assembly. The ac line voltage section contains three switches
(labeled S2, S3, and S4 on the rear panel) that configure the input to the transformer
to accept one of eight nominal line voltage levels. Also included in this section are a
simple unregulated power supply and a time delayed relay driver circuit. These
circuits control a shunt switch around a pair of surge current-limiting NTC
thermistors.
To avoid meter damage, do not measure the ac line voltage
section unregulated supply with a meter tied to earth ground.
55. Sense Amplifier Section
4-
Op amp U102, transistors Q100 through Q103, and their associated parts comprise the
forward gain elements of a precision ac amplifier. Since this monolithic device does not
accept supply voltages large enough to accommodate output swings of ±15.6V, a quartet
of discrete transistors is configured as an output stage with voltage gain. This provides
the necessary output swing of 11V rms as well as limits the additional forward gain of the
overall amplifier to simplify frequency compensation.
Inputs to the output voltage stage are derived from deviations of the supply current of
U102 from its quiescent value. This topology depends on the increase in current from a
particular power supply as the output of the monolithic op amp moves toward the value
of that power supply. This increasing current develops a drop across R108 for positive
output voltages or a drop across R116 for negative output voltages. These drops are
amplified by Q100 and Q103. Transistors Q101 and Q102 buffer the output signal to
present a low source impedance to the load.
Caution
4-32
Overall gain at low frequencies is controlled by Z100, a resistor network designed for
good ac frequency response, low power coefficient, and low thermal settling time. This
network provides a feedback ratio of 0.99, or a closed-loop gain of 0.01. As a result, the
entire sense amplifier is running in a virtual unity gain configuration. Zeners VR103 and
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