Agilent Technologies N3280A User Manual

USER’S GUIDE

Agilent Technologies

Model N3280A

Component Test DC Source

5

Agilent Part No. 5964-8248

Microfiche No. 5964-8249

June, 2001

Warranty Information

CERTIFICATION

Agilent Technologies certifies that this product met its published specifications at time of shipment from the factory.
Agilent Technologies further certifies that its calibration measurements are traceable to the United States National
Institute of Standards and Technology, to the extent allowed by the Bureau's calibration facility, and to the calibration
facilities of other International Standards Organization members.

WARRANTY

This Agilent Technologies hardware product is warranted against defects in material and workmanship for a period
of three years from date of delivery. Agilent Technologies software and firmware products, which are designated by
Agilent Technologies for use with a hardware product and when properly installed on that hardware product, are
warranted not to fail to execute their programming instructions due to defects in material and workmanship for a
period of 90 days from date of delivery. During the warranty period Agilent Technologies will, at its option, either
repair or replace products which prove to be defective. Agilent does not warrant that the operation for the software
firmware, or hardware shall be uninterrupted or error free.

For warranty service, with the exception of warranty options, this product must be returned to a service facility
designated by Agilent Technologies. Customer shall prepay shipping charges by (and shall pay all duty and taxes)
for products returned to Agilent Technologies for warranty service. Except for products returned to Customer from
another country, Agilent Technologies shall pay for return of products to Customer.

Warranty services outside the country of initial purchase are included in Agilent Technologies' product price, only if
Customer pays Agilent Technologies international prices (defined as destination local currency price, or U.S. or
Geneva Export price).

If Agilent is unable, within a reasonable time to repair or replace any product to condition as warranted, the
Customer shall be entitled to a refund of the purchase price upon return of the product to Agilent Technologies.

LIMITATION OF WARRANTY

The foregoing warranty shall not apply to defects resulting from improper or inadequate maintenance by the
Customer, Customer-supplied software or interfacing, unauthorized modification or misuse, operation outside of the
environmental specifications for the product, or improper site preparation and maintenance. NO OTHER
WARRANTY IS EXPRESSED OR IMPLIED. AGILENT TECHNOLOGIES SPECIFICALLY DISCLAIMS THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

EXCLUSIVE REMEDIES

THE REMEDIES PROVIDED HEREIN ARE THE CUSTOMER'S SOLE AND EXCLUSIVE REMEDIES. AGILENT
TECHNOLOGIES SHALL NOT BE LIABLE FOR ANY DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR
CONSEQUENTIAL DAMAGES, WHETHER BASED ON CONTRACT, TORT, OR ANY OTHER LEGAL THEORY.

ASSISTANCE

The above statements apply only to the standard product warranty. Warranty options, extended support contacts,
product maintenance agreements and customer assistance agreements are also available. Contact your nearest
Agilent Technologies Sales and Service office for further information on Agilent Technologies' full line of Support
Programs.

2

Safety Summary

F

y

s

y

The following general safety precautions must be observed during all phases of operation of this instrument.

ailure to comply with these precautions or with specific warnings elsewhere in this manual violates safet

tandards of design, manufacture, and intended use of the instrument. Agilent Technologies assumes no liabilit

for the customer's failure to comply with these requirements.

GENERAL

This product is a Safety Class 1 instrument (provided with a protective earth terminal). The protective features of
this product may be impaired if it is used in a manner not specified in the operation instructions.
Any LEDs used in this product are Class 1 LEDs as per IEC 825-1.

ENVIRONMENTAL CONDITIONS

This instrument is intended for indoor use in an installation category II, pollution degree 2 environment. It is
designed to operate at a maximum relative humidity of 95% and at altitudes of up to 4500 meters. Refer to the
specifications tables for the ac mains voltage requirements and ambient operating temperature range.

BEFORE APPLYING POWER

Verify that the product is set to match the available line voltage, the correct fuse is installed, and all safety
precautions are taken. Note the instrument's external markings described under "Safety Symbols".

GROUND THE INSTRUMENT

To minimize shock hazard, the instrument chassis and cover must be connected to an electrical ground. The
instrument must be connected to the ac power mains through a grounded power cable, with the ground wire firmly
connected to an electrical ground (safety ground) at the power outlet. Any interruption of the protective (grounding)
conductor or disconnection of the protective earth terminal will cause a potential shock hazard that could result in
personal injury.

ATTENTION: Un circuit de terre continu est essentiel en vue du fonctionnement sécuritaire de l'appareil.
Ne jamais mettre l'appareil en marche lorsque le conducteur de mise … la terre est d‚branch‚.

FUSES

Only fuses with the required rated current, voltage, and specified type (normal blow, time delay, etc.) should be
used. Do not use repaired fuses or short-circuited fuseholders. To do so could cause a shock or fire hazard.

Vous devrez impérativement utiliser des fusibles calibrés aux spécifications de courant, tension et type
(coupure, délai de coupure, etc ...). N'utilisez jamais de fusibles réparés et ne court-circuitez pas les supports
de fusibles. Sinon, vous risquez de provoquer un choc électrique ou un incendie.

DO NOT OPERATE IN AN EXPLOSIVE ATMOSPHERE

Do not operate the instrument in the presence of flammable gases or fumes.

DO NOT REMOVE THE INSTRUMENT COVER

Operating personnel must not remove instrument covers. Component replacement and internal adjustments must be
made only by qualified service personnel.

Instruments that appear damaged or defective should be made inoperative and secured against unintended
operation until they can be repaired by qualified service personnel.

3

SAFETY SYMBOLS

Direct current

Alternating current

Both direct and alternating current

Three-phase alternating current

Earth (ground) terminal

Protective earth (ground) terminal

Frame or chassis terminal

Terminal is at earth potential. Used for measurement and control circuits designed to be
operated with one terminal at earth potential.

Terminal for Neutral conductor on permanently installed equipment

Terminal for Line conductor on permanently installed equipment

WARNING

Caution

On (supply)

Off (supply)

Standby (supply). Units with this symbol are not completely disconnected from ac mains when
this switch is off. To completely disconnect the unit from ac mains, either disconnect the power
cord or have a qualified electrician install an external switch.

In position of a bi-stable push control

Out position of a bi-stable push control

Caution, risk of electric shock

Caution, hot surface

Caution (refer to accompanying documents)

The WARNING sign denotes a hazard. It calls attention to a procedure, practice, or the like,
which, if not correctly performed or adhered to, could result in personal injury. Do not proceed
beyond a WARNING sign until the indicated conditions are fully understood and met.

The CAUTION sign denotes a hazard. It calls attention to an operating procedure, or the like,
which, if not correctly performed or adhered to, could result in damage to or destruction of part
or all of the product. Do not proceed beyond a CAUTION sign until the indicated conditions
are fully understood and met.

4

Declaration Page

Manufacturer’s Name:
Manufacturer’s Address:

declares that the product:

Product Name:

DECLARATION OF CONFORMITY

According to ISO/IEC Guide 22 and CEN/CENELEC EN 45014

Responsible Party Alternate Manufacturing Site
Agilent Technologies, Inc. Agilent Technologies
Power Products PGU
140 Green Pond Road
Rockaway, New Jersey 07866
U.S.A

Component Test dc Source

South Queensferry
West Lothian EH30 9TG
United Kingdom

Model Number:

Product Options:

Conforms with the following European Directives:

The product herewith complies with the requirements of the Low Voltage Directive 73/23/EEC and the EMC
Directive 89/336/EEC (including 93/68/EEC) and carries the CE Marking accordingly

EMC information:

The product herewith complies with the requirements of the EMC Directive 89/336/EEC (including
93/68/EEC) and carries the CE Marking accordingly (European Union).

As detailed in

Assessed by:

Safety information:

The product herewith complies with the requirements of the Low Voltage Directive 73/23/EEC and
carries the CE-marking accordingly

N3280A

This declaration covers all options of the above product(s).

Electromagnetic Compatibility (EMC) Certificate of Conformance No.TCF
CC/TCF/01/016 based on Technical Construction File (TCF) No. ANJ13, dated
8/03/2001

Celestica Ltd, Appointed Competent Body
Westfields House, West Avenue
Kidsgrove, Stoke-on-Trent
Straffordshire, ST7 1TL
United Kingdom

Supplemental information

The product conforms to the following safety standards:

IEC 1010-1:1990+A1+A2 / EN 61010-1:1993 +A2
UL 3111-1:1994
CSA C22.2 No. 1010.1:1993

March 19, 2001
Date Hank Kowalla / Quality Manager at PPPGU

For further information, please contact your local Agilent Technologies sales office, agent or distributor.
Authorized EU-representative: Agilent Technologies Deutschland GmbH, Herrenberger Stra
Böblingen, Germany

βe 130, D71034

5

Acoustic Noise Information

Herstellerbescheinigung

Diese Information steht im Zusammenhang mit den Anforderungen der
Maschinenläminformationsverordnung vom 18 Januar 1991.

* Schalldruckpegel Lp <70 dB(A)
* Am Arbeitsplatz
* Normaler Betrieb
* Nach EN 27779 (Typprüfung).

Manufacturer's Declaration

This statement is provided to comply with the requirements of the German Sound Emission Directive,
from 18 January 1991.

* Sound Pressure Lp <70 dB(A)
* At Operator Position
* Normal Operation
* According to EN 27779 (Type Test).

Printing History

The edition and current revision of this manual are indicated below. Reprints of this manual containing
minor corrections and updates may have the same printing date. Revised editions are identified by a new
printing date. A revised edition incorporates all new or corrected material since the previous printing
date.

Changes to the manual occurring between revisions are covered by change sheets shipped with the
manual. In some cases, the manual change applies only to specific instruments. Instructions provided on
the change sheet will indicate if a particular change applies only to certain instruments.

This document contains proprietary information protected by copyright. All rights are reserved. No part
of this document may be photocopied, reproduced, or translated into another language without the prior
consent of Agilent Technologies. The information contained in this document is subject to change
without notice.

 Copyright 2001 Agilent Technologies, Inc. Edition 1 March, 2001
Update 1 June, 2001

6

Table of Contents

Warranty Information 2
Safety Summary 3
Declaration Page 5
Acoustic Noise Information 6
Printing History 6
Table of Contents 7

GENERAL INFORMATION 13

Document Orientation 13
Safety Considerations 13
Options and Accessories 14
Description 14

Remote Programming 14

Output Characteristics 15

Voltage Priority Operation 15
Current Priority Operation 16

Measurement Characteristics 17

Start of a Measurement 18

INSTALLATION 19

Inspection 19

Damage 19
Packaging Material 19
Additional Items 19
Cleaning 19

Location 20

Bench Operation 20
Rack Mounting 20

Power Connections 21

Connect the Power Cord 21

Output Connections 22

Outputs 1 - 4 22
Current Ratings 23
Voltage Drops and Lead Resistance 23
Coaxial Guard Connections 24
Maintaining Stability 25
OVP Considerations 25

External Trigger Connections 25
Computer Connections 25

GPIB Interface 25
GPIB Address 26

TURN-ON CHECKOUT 27

Front Panel Description 27
Checkout Procedure 28
In Case of Trouble 29

Selftest Error Messages 29
Runtime Error Messages 29
Line Fuse 29

7

INTRODUCTION TO PROGRAMMING 31

External References 31

GPIB References 31
SCPI References 31

GPIB Capabilities of the DC Source 31
Introduction to SCPI 32

Conventions Used in This Guide 32

Types of SCPI Commands 32

Multiple Commands in a Message 33
Moving Among Subsystems 33
Including Common Commands 33
Using Queries 33

Types of SCPI Messages 34

The Message Unit 34
Channel List Parameter 34
Headers 35
Query Indicator 35
Message Unit Separator 35
Root Specifier 35
Message Terminator 35

SCPI Data Formats 35

Numerical Data Formats 35
Suffixes and Multipliers 36
Response Data Types 36

SCPI Command Completion 36
Using Device Clear 37

PROGRAMMING THE DC SOURCE 39

Introduction 39
Programming the Output 39

Power-on Initialization 39
Enabling the Output 39
Output Voltage 39
Overvoltage Protection 40
Output Current 40
Output Mode 40
Oscillation Protection 41

Triggering Output Changes 41

Output Trigger Model 41
Setting the Voltage and Current Trigger Levels 42
Enabling the Output Trigger System 42
Selecting the Output Trigger Source 42
Generating Output Triggers 43

Making Measurements 43

Average Measurements 43
Power Line Cycles 44
Measurement Samples and Time Interval 44
Current Ranges 45
Window Functions 45
Returning All Measurement Data From the Data Buffer 45

Triggered Measurements 45

Measurement Trigger Model 46
Enabling the Measurement Trigger System 46
Selecting the Measurement Trigger Source 46
Selecting the Sensing Function 47
Output Settling Delay 47
Generating Measurement Triggers 47

8

Pre-trigger and Post-trigger Data Acquisition 48

Programming the Status Registers 49

Operation Status Group 50
Questionable Status Group 51
Standard Event Status Group 51
Status Byte Register 51
Determining the Cause of a Service Interrupt 52
Servicing Operation Status and Questionable Status Events 52

LANGUAGE DICTIONARY 53

Introduction 53

Subsystem Commands 53
Common Commands 53
Programming Parameters 53

SCPI Programming Commands - At a Glance 54
Calibration Commands 57

CALibrate:CURRent 57
CALibrate:CURRent:LIMit[:POSitive] CALibrate:CURRent:LIMit:NEGative 57
CALibrate:CURRent:MEASure 57
CALibrate:DATA 58
CALibrate:DATE 58
CALibrate:LEVel 58
CALibrate:PASSword 58
CALibrate:SAVE 59
CALibrate:STATe 59
CALibrate:VOLTage 59

Measurement Commands 60

FETCh:ARRay:CURRent? FETCh:ARRay:VOLTage? 60
FETCh:CURRent? FETCh:VOLTage? 60
MEASure:ARRay:CURRent? MEASure:ARRay:VOLTage? 61
MEASure:CURRent? MEASure:VOLTage? 61
SENSe:CURRent:RANGe 61
SENSe:FUNCtion 62
SENSe:SWEep:NPLCycles 62
SENSe:SWEep:OFFSet:POINts 62
SENSe:SWEep:POINts 63
SENSe:SWEep:TINTerval 63
SENSe:WINDow 63

Output Commands 64

OUTPut 64
OUTPut:OSCProtect 64
OUTPut:PROTection:CLEar 64
[SOURce:]CURRent[:IMMediate] [SOURce:]CURRent:TRIGgered 65
[SOURce:]CURRent:LIMit[:IMMediate] [SOURce:]CURRent:LIMit:TRIGgered 65
[SOURce:]CURRent:LIMit:BWIDth 65
[SOURce:]CURRent:MODE [SOURce:]CURRent:LIMit:MODE 66
[SOURce:]DELay 66
[SOURce:]DELay:MODE 66
[SOURce:]FUNCtion:MODE 67
[SOURce:]VOLTage:ALC:BWIDth 67
[SOURce:]VOLTage[:IMMediate] [SOURce:]VOLTage:TRIGgered 67
[SOURce:]VOLTage:MODE 68
[SOURce:]VOLTage:PROTection:STATe 68

Status Commands 69

STATus:OPERation[:EVENt]? 69
STATus:OPERation:CONDition? 69
STATus:OPERation:ENABle 69

9

STATus:OPERation:NTR STATus:OPERation:PTR 70
STATus:PRESet 70
STATus:QUEStionable[:EVENt]? 70
STATus:QUEStionable:CONDition? 71
STATus:QUEStionable:ENABle 71
STATus:QUEStionable:NTR STATus:QUEStionable:PTR 71

System Commands 72

SYSTem:ERRor? 72
SYSTem:VERSion? 72

Trigger Commands 73

ABORt 73
INITiate:NAME 73
TRIGger:ACQuire 73
TRIGger:ACQuire:SOURce 74
TRIGger[:TRANsient]:SOURce 74
TRIGger[:TRANsient] 74

Common Commands 75

*CLS 75
*ESE 75
*ESR? 75
*IDN? 76
*OPC 76
*OPT? 76
*RST 77
*SRE 77
*STB? 77
*TRG 78
*TST? 78
*WAI 78

SPECIFICATIONS 79

Introduction 79

PERFORMANCE TESTS AND CALIBRATION 83

Introduction 83
Equipment Required 83
Performance & Verification Tests 84

Measurement Techniques 84
Electronic Load 85
Programming 85
Test Setup 85

Voltage Priority Tests 86

Voltage Programming and Readback Accuracy 86
Positive Current Limit (+CL) 86
Negative Current Limit (-CL) 87

Current Priority Tests 88

Current Programming and Readback Accuracy 88

Load Effect Tests 89

Voltage Priority, Constant Voltage Load Effect 89
Voltage Priority, +Current Limit Load Effect 90
Voltage Priority, -Current Limit Load Effect Test 90
Current Priority Constant Current Test 91

Source Effect Tests 91

Voltage Priority, Constant Voltage Source Effect 91
Voltage Priority, +Current Limit Source Effect 92
Voltage Priority, -Current Limit Source Effect 92

10

Current Priority, Constant Current Source Effect 93

Ripple and Noise Tests 94

Voltage Priority Ripple and Noise 94
Current Priority Ripple and Noise 95

Transient Response Tests 95

Voltage Priority, Transient Recovery Time 95
Current Priority Transient Recovery Time 96

Performance Test Equipment Form 97
Performance Test Record Form 98
Performing the Calibration Procedure 99

Enable Calibration Mode 99
Voltage Priority Mode Programming and Measurement Calibration 99
Negative Current Limit Calibration 100
Positive Current Limit Calibration 100

0.5A Range Current Measurement Calibration 100
15mA Range Current Measurement Calibration 101
Current Priority Mode Programming and 0.5mA Range Measurement Calibration 101
Saving the Calibration Constants 101
Changing the Calibration Password 102
Calibration Error Messages 102

ERROR MESSAGES 103

Error Number List 103

LINE VOLTAGE SELECTION 107

EARLIER VERSION OUTPUT CONNECTORS 109

Mating Connector Part Numbers 109
Rear Panel Pinout Assignments 109

INDEX 111

11

1

General Information

Document Orientation

This manual describes the operation of the Agilent Model N3280A Component Test DC Source. Unless
otherwise noted, the unit will be referred to by the description "dc source" throughout this manual.

The following Getting Started Map is a general guide to the location of information in this manual. Refer
to the table of contents or index for a complete list of information.

Getting Started Map

Task Where to find information

General information

Capabilities and characteristics

Installing the unit

Line connections
Load connections
Computer connections

Checking out the unit

Verifying proper operation

Using the programming interface

GPIB interface

Programming the unit using SCPI commands

SCPI commands
SCPI programming examples
SCPI language dictionary

Specifications

Verifying and Calibrating the Unit

Chapter 1

Chapter 2

Chapter 3

Chapter 4

Chapters 5 and 6

Appendix A

Appendix B

Safety Considerations

This dc source is a Safety Class 1 instrument, which means it has a protective earth terminal. That
terminal must be connected to earth ground through a power source equipped with a ground receptacle.
Refer to the Safety Summary page at the beginning of this guide for general safety information. Before
installation or operation, check the dc source and review this guide for safety warnings and instructions.
Safety warnings for specific procedures are located at appropriate places in the guide.

13

1 - General Information

Options and Accessories

Table 1-1. Options

Option Description

100
220
230

8ZL Add instrument feet - for bench mounting (p/n 5041-9167)

1

AXS

1

1CM

1

Support rails are required when rack mounting units. Use E3663A support rails for Agilent rack cabinets. If you are

using non-Agilent rack cabinets, contact the rack manufacturer to obtain support rails for your cabinet.

Item Part Number

GPIB cables 1.0 meter (3.3 ft) Agilent 10833A

Rack mount with slide - for two side-by-side units Order 5063-9255 and 1494-0015
Rack mount with slide - for one unit Order 5063-9255, 1494-0015, and 5002-3999

87−106 Vac, 47−63 Hz
191−233 Vac, 47−63 Hz
207−253 Vac, 47−63 Hz

Rack mount kit for two side-by-side N3280A units. Consists of:
Lock-link kit (p/n 5061-9694), Flange kit (p/n 5063-9212), Tie bracket (p/n 5002-1587)
Rack mount kit for one unit (p/n 5063-9240)

Table 1-2. Accessories

2.0 meters (6.6 ft) Agilent 10833B

4.0 meters (13.2 ft) Agilent 10833C

0.5 meters (1.6 ft) Agilent 10833D

Description

The Agilent Model N3280A Component Test DC Source is a quad output dc power supply designed to
simplify the testing of integrated circuits. It has the following key features and performance capabilities:

♦ High density – four isolated outputs in a 2U half-rack package
♦ Four quadrant bipolar output
♦ High programming and measurement accuracy (refer to Appendix A)
♦ Active guard available for accurate current measurements
♦ Solid-state output and sense terminal disconnect relays
♦ High GPIB throughput

Additional features include:

♦ Positive and negative overvoltage protection shutdown
♦ Over-temperature and oscillation protection
♦ Programmable current limit in voltage priority mode

Remote Programming

NOTE: With the exception of the power switch, there are no front panel controls for the Agilent

N3280A dc source. The N3280A can be controlled only with SCPI programming commands.

The dc source may be remotely programmed via the GPIB bus. GPIB programming is with SCPI
commands (Standard Commands for Programmable Instruments), which make dc source programs
compatible with those of other GPIB instruments. Dc source status registers allow remote monitoring of a
wide variety of operating conditions. Refer to chapters 5 and 6 for more information.

14

General Information - 1

Output Characteristics

Voltage Priority Operation

Each Agilent N3280A output is a four-quadrant bipolar dc source that can be operated in either voltage
or current priority mode. In voltage priority mode the output is controlled by a bi-polar constant voltage
feedback loop, which maintains the output voltage at its positive or negative programmed setting. The
output voltage will remain at its programmed setting as long as the load current remains within the
positive or negative current limit. A single positive value programs both the positive and negative current
limit.

Figure 1-1 shows the voltage priority operating characteristics of the dc source. The area in quadrants 1
and 3 shows the characteristics of the output when it is being operated as a source (sourcing power). The
area in quadrants 2 and 4 shows the characteristics of the output when it is being operated as a load
(sinking power).

+ 10.25V

-

- 10.25V

- 512.5mA

+ OV

-I limit

Output
Voltage

+

V setting

1+

324

+I limit

-

- OV

+ 512.5mA

Key

Sinking power

Sourcing power

Programmable

Output
Current

Figure 1-1. Output Characteristic (Voltage Priority)

The heavy line illustrates the locus of possible operating points as a function of the output load, which
may be purely resistive, or possibly include external voltage or current sources. In voltage priority mode,
the constant voltage loop will regulate the output voltage as the load changes, unless the output current
attempts to exceed the current limit setting.

If this occurs, either the negative or the positive current limit loop will regulate the output current at the
programmed value. Either a CV (constant voltage), CL+ (positive current limit), or CL− (negative current
limit) status flag is set to indicate which loop is presently controlling the output.

15

1 - General Information

If the output voltage exceeds either the positive or negative overvoltage set point, the output will shut
down and be disabled, automatically opening the output and sense relays. This leaves the output in a
high-impedance state.

The full ±512.5 milliampere output current is available only in voltage priority mode. In this mode, the
output voltage should be programmed to the desired positive or negative value. A positive current limit
value should also be programmed. Note that the negative current limit tracks the positive current limit set
point. The output will regulate at the desired voltage level, provided that the current limit has been set
higher that the actual output current requirement of the external load. Note that if the current limit is set
to a value between zero and 75 µA, the actual current limit will be ±75 µA. Thus, it is not possible to
program current limit values less than 75 µA in voltage priority mode. (This limitation does not apply in
current priority mode.)

Current Priority Operation

Each Agilent N3280A output is a four-quadrant bipolar dc source that can be operated in either voltage
or current priority mode. In current priority mode the output is controlled by a bi-polar constant current
feedback loop, which maintains the output current (source or sink) at its programmed setting. The output
current will remain at its programmed setting as long as the load voltage remains within the positive and
negative voltage limits. The voltage limits are not programmable and vary somewhat with the output
current. When the output current is zero, the voltage limits are typically ±10.75 V.

Figure 1-2 shows the current priority operating characteristics of the dc source. The area in quadrants 1
and 3 shows the characteristics of the unit when it is being operated as a source (sourcing power). The
area in quadrants 2 and 4 shows the characteristics of the unit when it is being operated as a load (sinking
power).

+ 12V

-

+V limit

Output
Voltage

+

+ 10.75V

+VL status set

I setting

132

4

Key

Sinking power

Sourcing power

Programmable

+ 9.5V

+

Output
Current

16

- 9.5V

- 0.5125mA

-VL status set

- 10.75V

-

-V limit

+ 0.5125mA

- 12V

Figure 1-2. Output Characteristic (Current Priority)

General Information - 1

The heavy line illustrates the locus of possible operating points as a function of the output load, which
may be purely resistive, or possibly include external voltage or current sources. In current priority mode,
the constant current loop will regulate the output current as the load changes, until the positive or
negative voltage limit is reached. A CC (constant current) status flag indicates when the current loop is
controlling the output.

If the output voltage reaches either the positive or negative voltage limit, the unit no longer operates in
constant current mode and the output current is no longer held constant. Instead, the output current is
limited at either the positive or negative voltage limit line. When the unit is sinking power, the output
voltage will continue to increase in the positive or negative direction as more current is forced into the
unit. Note that a VL+ (positive voltage limit) or VL− (negative voltage limit) status bit will be set to
register a voltage limit at about 0.8 V before the positive or negative voltage line is reached.

The maximum current available in current priority mode is about 0.5 mA, which is ideal for testing
sensitive devices such as input diodes. In this mode, the output current must be programmed to the
desired positive or negative value. However, the positive and negative voltage limits are not
programmable, and vary with the actual output current as shown in the figure. The typical positive
voltage limit ranges from about 10.75V at no load to about 9.5V at full load. The typical negative voltage
limit ranges from about –10.75V to about –9.5V.

NOTE: Overvoltage protection is not functional in current priority mode.

Measurement Characteristics

The N3280A uses a digitizing measurement system with a single timebase for all output channels. The
number of measurement samples and the sampling interval of the timebase can be explicitly programmed.
These values will apply to measurements taken on all outputs. For example, if simultaneous
measurements are made on four output channels and one of the three channels is set to one power line
cycle (PLC), then all three channels will be set to one power line cycle per measurement.

Conversely, each output channel of the N3280A has its own measurement buffer. This means that each
output can be configured to measure a different parameter (either voltage or current), and a different
current range. However, the number of measurement samples and sampling interval for each type of
measurement is the same for all channels.

There is one voltage measurement range and three current measurement ranges. The current range must
be selected explicitly. If a measured value exceeds the presently selected range, an error message is
returned. Voltage measurements and current measurements using the 0.5A or 15mA range can be made to
full accuracy using the default measurement sample (5 data points @30.4µs intervals = 152 µs). To
achieve full accuracy on the 0.5mA current range, a longer sampling interval of one power line cycle
(PLC) is required to filter out line noise. Thus, a full accuracy measurement on the 0.5mA current range
will typically take between 18 and 21.3 ms, depending on the line frequency.

Note that faster measurements using lower PLC values (<1) are only appropriate for loads that do not
draw currents with a significant noise component. If the load current is noisy, it may be necessary to
increase the sampling interval to provide additional filtering.

All voltage and current measurements return the average value of the samples taken. Measurements can
be made using either a Rectangular or Hanning window. The default Rectangular window is used on all

17

1 - General Information

measurement ranges to make fast measurements. The Hanning window can be used to reduce errors
caused by other periodic noise sources, provided that the sample period is long enough to capture three or
more noise waveform cycles. Using a Hanning window will result in slower measurement speed.

Start of a Measurement

The dc source delays the start of a measurement until a previous output voltage or current change has
settled. When voltage or current settings are changed in either voltage priority or in current priority
mode, an internal timer is started that delays any subsequent measurements. At power-on or after *RST
this delay allows the output to settle to better than 0.1% of its final value. In voltage priority mode, the
final value is based on a 20 ohm load. In current priority mode, the final value is based on a short-circuit
load.

The settling delay can also be explicitly programmed. This may be required, for example, if the load
requires more or less delay than the representative load or if the measurement requires less accuracy.

18

2

Installation

Inspection

Damage

When you receive your dc source, inspect it for any obvious damage that may have occurred during
shipment. If there is damage, notify the shipping carrier and the nearest Agilent Sales and Support Office
immediately. The list of Agilent Sales and Support Offices is at the back of this guide. Warranty
information is printed in the front of this guide.

Packaging Material

Until you have checked out the dc source, save the shipping carton and packing materials in case the unit
has to be returned. If you return the dc source for service, attach a tag identifying the owner's name and
address, the model number, and a brief description of the problem.

Additional Items

Table 2-1. Items Supplied

Item Part Number Description

Power Cord contact the nearest Agilent

Sales and Support Office

4 - Output
connectors

Trigger
connector

Line Fuse 2110-0638

User's Guide 5964-8248 This manual.

1253-4893 A 6-terminal connector plug for connecting the output,

1252-8670 3-terminal digital plug for connecting the trigger input

2110-0773

A power cord appropriate for your location.

sense, ground, and guard. The connector installs in the
back of the unit.

signal. The connector installs in the back of the unit.

3.15 AT (time delay) for 100/120 Vac operation

1.6 AT (time delay) for 220/230 Vac operation

Cleaning

Use a dry cloth or one slightly dampened with water to clean the external case. Do NOT open the unit.

WARNING: To prevent electric shock, unplug the unit before cleaning.

19

2 - Installation

Location

Figure 2-1 gives the dimensions of your dc source. The dc source must be installed in a location that
allows enough space at the sides and back of the unit for adequate air circulation (see Bench Operation).

NOTE: This dc source generates magnetic fields that may affect the operation of other

instruments. If your instrument is susceptible to operating magnetic fields, do not locate
it in the immediate vicinity of the dc source. Typically, at 5 millimeters from the dc
source, the electromagnetic field is less than 5 gauss. Many CRT’s, such as those used in
computer displays, are susceptible to magnetic fields much lower than 5 gauss. Check
susceptibility before mounting any display near the dc source.

Bench Operation

Do not block the fan exhaust at the rear of the unit.

A fan cools the dc source by drawing air in through the sides and exhausting it out the back. Minimum
clearances for bench operation are 1 inch (25 mm) along the sides.

Rack Mounting

The dc source can be mounted in a standard 19-inch rack panel or cabinet. Table 1-1 documents the part
numbers for the various rack mounting options that are available for the dc source. Installation
instructions are included with each rack mount option.

NOTE: Support rails or an instrument shelf is required when rack mounting units.

20

Figure 2-1. Outline Diagram

Installation - 2

Power Connections

Connect the Power Cord

Connect the power cord to the IEC 320 connector on the rear of the unit. If the wrong power cord was
shipped with your unit, contact your nearest Agilent Sales and Support Office to obtain the correct cord
(refer to the list at the back of this guide).

Check the line voltage rating label on the back of the unit to make sure that it agrees with your ac mains
voltage. Refer to appendix E if the voltage at your site is different from the voltage indicated on the unit.

Figure 2-2 identifies all rear panel connections on the dc source.

1 42 3 5

QQQQ GPIB

connector

RRRR Trigger Connector

SSSS Address Switch

TTTT Output

Connectors (4)

UUUU Line

Figure 2-2. Rear Panel Connectors and Switches

GPIB connector for computer connection.

A 3-terminal trigger input connector. Only the center and left-most
terminals are used.

Switch to select GPIB address. Refer to the end of this chapter.

Pin 1 = Active guard
Pin 2 = High sense
Pin 3 = High output
Pin 4 = Low output
Pin 5 = Low sense
Pin 6 = chassis ground connection

AC line cord is installed here. Also used to set the ac line voltage see
Appendix E.

21

2 - Installation

Output Connections

Turn the unit off before connecting any wires.

Outputs 1 - 4

Disconnect the mating plug from the unit by pulling it straight back.

The output connectors (outputs 1-4) have a termination for the Hi and Lo output terminals, the Hi and Lo
sense terminals, a guard terminal, and an earth ground terminal (see figure 2-3). For proper operation of
the dc source, you must connect the Hi sense and Lo sense terminals to their respective high and low
monitoring points. Install the connector plug with its sense terminals connected before applying power to
the unit.

CAUTION: Connect the sense leads carefully so that they do not become open-circuited. If the sense

leads are left unconnected or become open during operation, the dc source will revert to
a local sense mode using internal sense protect resistors. This will result in an incorrect
voltage being applied at the load terminals.

The 6-pin connector is removable and accepts wires sizes from AWG 28 to AWG 16. Insert the wire into
the wire terminal, then use a small, flat-bladed screwdriver to tighten the wire terminal. Agilent
Technologies does not recommend using wire sizes smaller than AWG 24. After you insert the mating
plug into the output connector, tighten the two locking screws to secure the connection.

OUTPUT 1
MATING PLUG

TIGHTEN SCREWS

LOCKING SCREW

INSERT WIRES

TWIST PAIR

SHOWN

Hsen Hi Lo Lsen

TWIST LEADS

_

LOAD

+

Figure 2-3. Remote Sense Connections

Figure 2-4 shows how to connect remote sense and load leads when using a removable test fixture. For
best transient response and load regulation, keep the resistance and inductance as low as possible, as
illustrated in the figure. The addition of a low-leakage RC network may help improve output transient
response when the unit is operating in voltage priority mode.

22

TIGHTEN SCREWS

Installation - 2

OUTPUT 1
MATING PLUG
SHOWN

LOCKING SCREW

INSERT WIRES

Current Ratings

Hsen Hi Lo Lsen

TWIST LEADS

TWIST PAIR

ADDITION OF LOW-LEAKAGE

RC NETWORK MAY IMPROVE

TRANSIENT RESPONSE IN

VOLTAGE PRIORITY MODE.

KEEP RESISTNCE AND
INDUCTANCE LOW.
USE TWISTED PAIR OR
SANDWICHED PCB TRACKS.

_

+

FIXTURE

CONNECTIONS

Figure 2-4. Remote Sense Connections with Test Fixture

LOAD

The following table lists the characteristics of AWG (American Wire Gauge) copper wire for some
common wire sizes that can be accommodated in the output connectors.

Table 2-2. Ampacity and Resistance of Stranded Copper Conductors

AWG No. Maximum Ampacity (in

free air)

Resistance (at 20 deg. C)

ΩΩΩΩ/m ΩΩΩΩ/ft

24 3.52 0.0843 0.0257
22 5.0 0.0531 0.0162
20 8.33 0.0331 0.0101
18 15.4 0.0210 0.00639
16 19.4 0.0132 0.00402

Voltage Drops and Lead Resistance

To optimize the performance and transient response in your test system, please observe the following
guidelines:

♦ Twist the load leads together and keep them short. The shorter the leads, the better the performance.

♦ Twist the sense leads together, but do not bundle the sense leads with the load leads.

♦ For best performance, keep the total cable length to the load to about 5 meters (15 ft) or less.

The load wires must also be of a diameter large enough to avoid excessive voltage drops due to the
impedance of the wires. In general, if the wires are heavy enough to carry the maximum short circuit
current without overheating, excessive voltage drops will not be a problem.

23

2 - Installation

NOTE: Any voltage drop in the load leads must be subtracted from the full-scale voltage

available at the output terminals.

Coaxial Guard Connections

An active guard connection is available at the output connector. When the guard connection is extended
to a test fixture for example, it can be used to eliminate the effects of leakage current that can exist
between the Hi and Lo output terminals when testing high-impedance devices. In particular, the Hi output
terminal and the Hi sense terminal may benefit from guarding. In this way, any leakage current that is not
load current will be collected by the circuit and not be included in the output current measurement.

The guard connection is always enabled and provides a buffered voltage that is at approximately the
same potential as the Hi output terminal. The output impedance of the guard is approximately 2.1K
ohms.

If you are using tri-axial cables to extend the guard connection to the test fixture, use the center
connector for the Hi connection, the inner shield for the guard connection, and the outer shield as the Lo
connection (see figure 2-5).

OUTPUT 1
MATING PLUG

TIGHTEN SCREWS

SHOWN

LOCKING SCREW

INSERT WIRES

Hsen Hi Lo Lsen

TRIAXIAL CABLE

TEST FIXTURE

_

+

GUARD SHIELD

Figure 2-5. Guard Connections for Test Fixtures

24

Installation - 2

Maintaining Stability

In voltage priority mode, the constant voltage loop has the following three compensation bandwidths:

♦ 30 kHz, 20 kHz; and 10 kHz

In current limit operation, only two compensation bandwidths are available:

♦ 30 kHz and 10 kHz

If the output of your unit is being shut down by the oscillation protection circuit because of long load
wires or a high Q load impedance, you can reprogram the output compensation bandwidth to try and
eliminate the oscillation. As shipped from the factory, the compensation bandwidth is set to 30 kHz.

OVP Considerations

CAUTION: Disabling the OVP protection circuit may cause excessive output voltages, such as can

occur if remote sense leads are shorted, to damage the equipment under test.

The dc source is shipped from the factory with its overvoltage protection circuit enabled. You can disable
the OVP circuit using the VOLTage:PROTection:STATe command as explained in chapter 6. The
overvoltage circuit automatically turns the output off and opens the output relays if the output voltage
exceeds +11.5V (±0.3V) or −11.5V (±0.3V)

External Trigger Connections

This rear panel connector has an external trigger input.

The trigger input pin is normally at a TTL high level. To generate a trigger, you can provide a negative­going TTL signal to the trigger input, or momentarily connect a short (contact closure) from the trigger
input pin to the chassis ground pin on the trigger connector. In any case, the device that you use to
implement the trigger must be able to sink approximately 1mA.

The external trigger input can trigger both output voltage/current changes and output measurements.

Computer Connections

The dc source can be controlled through a GPIB interface.

GPIB Interface

Follow the GPIB card manufacturer's directions for card installation and software driver setup. Dc
sources may be connected to the GPIB interface in series configuration, star configuration, or a
combination of the two, provided the following rules are observed:

♦ The total number of devices including the GPIB interface card is no more than 15.

♦ The total length of all cables used is no more than 2 meters times the number of devices connected

together, up to a maximum of 20 meters. (Refer to table 1-2 for a list of available GPIB cables.)

♦ Do not stack more than three connector blocks together on any GPIB connector.

♦ Make sure all connectors are fully seated and the lock screws are firmly finger-tightened.

25

2 - Installation

GPIB Address

Each dc source has its own GPIB bus address, which can be set using the rear panel Address switch. The
dc source is shipped with its GPIB address set to 5. Refer to the following table for additional address
switch positions.

4 3 2 1 0

1

0

Address = 5

Handle

Table 2-3. Settings for Power Module Configuration Switch

GPIB Switch Setting GPIB Switch Setting

Address 4 3 2 1 0 Address 4 3 2 1 0

000000801000
100001901001
2 0 001 0 10 01 0 10
3 0 001 1 11 01 0 11
4 0 010 0 12 01 1 00

5

00101 13 01I01
6 0 011 0 14 01 1 10
7 0 011 1 15 01 1 11

26

Turn-On Checkout

Front Panel Description

N3280A 10V, 0.5A

Component Test DC Source

3

1 2 3

QQQQ Line

Switch

RRRR Unit

Indicators

SSSS Channel

Indicators

Figure 3-1. Front Panel, Overall View

AC mains power switch.

Unit indicators light to indicate the following operating conditions:

Power The dc source is turned on.
Active The dc source is addressed to talk or listen.
Error There is a message in the SCPI error queue.

Channel indicators light to indicate the following channel conditions:

On The specified output channel is enabled.
Prot The specified output channel has entered protection mode due to:

Overtemperature,
Overvoltage,
Oscillation protect, or
Power clear.
Query the status registers of the affected channel to determine which
protection feature is tripped.

27

3 – Turn-On Checkout

Checkout Procedure

Successful tests in this chapter provide a high degree of confidence that your unit is operating properly.
Complete performance tests are given in Appendix B.

NOTE: To perform the checkout procedure, you will need a computer with a GPIB interface.

You will also need a digital multimeter for making voltage and current measurements.

If you have not already done so, connect your unit to the computer's GPIB interface. Also connect the
power cord to the unit and plug it in.

Procedure Explanation

1. Connect the Hi sense terminal to the Hi
terminal. Connect the Lo sense terminal to
the Lo terminal. Connect the voltage inputs
of the voltmeter across the Hi and Lo sense
terminals of output 1.

2. Turn the unit on. The unit undergoes a self­test when you first turn it on.

3. Check that the fan is on. You should be able to hear the fan and feel air coming from

4.

Program

5.

Program "

6. Create a variable for a measurement.
Program
Read the variable value.

7.

Program

8.

Program
Read the variable value.

9.

Program

"Output On, (@1)"

Voltage 10, (@1)"

"Measure:Voltage? (@1)"

"Voltage -10, (@1)"

"Measure:Voltage? (@1)"

"Output Off, (@1)"

The external voltmeter is used to verify the output.

During selftest, all indicators light simultaneously and then
light individually in a clockwise manner to test the
functionality of the display

the back of the unit.

Turn the output on.

Check the voltmeter display to verify the voltage
programming.

Reads the voltage of output 1.
This should agree with the value displayed on the voltmeter.

Check the voltmeter display to verify the voltage
programming.

Reads the voltage of output 1.
This should agree with the value displayed on the voltmeter.

Turn the output off.

10. Connect the current measurement inputs of
the ammeter across Hi and Lo output
terminals of output 1. Observe polarity.

11.

Program

12.

Program

13.

Program

14. Create a variable for a measurement.
Program
Read the variable value.

15.

Program
Disconnect the multimeter.

16. Repeat steps 3 through 15 for outputs 2, 3,
and 4.

"Output On, (@1)"

"Function:Mode CURR, (@1)"

"Current 0.0005, (@1)"

"Measure:Current? (@1)"

"Output Off, (@1)"

28

Use the ammeter to short the output of the unit and verify the
output current.

Turn the output on.

Program the unit for current priority mode.

Reads the current of output 1.
This should agree with the value displayed on the ammeter.

Turn the output off.

Substitute the channel that you are programming after the @
symbol. For example, if you are programming channel 2,
program "(@2)" in all commands.

Turn-On Checkout - 3

In Case of Trouble

Dc source failure may occur during power-on selftest or during operation. Either the Error or the Prot
indicator on the front panel may be lit to indicate that a failure has occurred. If this occurs, turn the
power off and then back on to see if the error persists. If the error persists, the dc source requires service.

Selftest Error Messages

Error numbers and messages are read back with the SYSTem:ERRor? query. SYSTem:ERRor? returns
an NR1 and a string error message.

Table 3-1. Power-On Selftest Errors

Error No. Failed Test

Error 0 No error

Error 1

Error 2

Error 3

Error 4

Error 5

Error 10

Output 1 non-volatile RAM CAL section checksum failed

Output 2 non-volatile RAM CAL section checksum failed

Output 3 non-volatile RAM CAL section checksum failed

Output 4 non-volatile RAM CAL section checksum failed

Non-volatile RAM CONFIG section checksum failed

RAM selftest

Runtime Error Messages

Appendix C lists other error messages that may appear at runtime.

Line Fuse

If the dc source appears "dead" with the Power LCD off and the fan is not running, check your ac mains
to be certain line voltage is being supplied to the dc source. Also check that the line module on the rear of
the unit is set to the correct voltage. If the ac mains is normal, the internal line fuse may be defective.

Refer to Appendix E and follow the procedure described in the appendix for accessing and replacing the
line fuse located inside the unit. Unless the line voltage setting is incorrect, do not change the line
voltage setting.

NOTE: If the dc source has a defective fuse, replace it only once. If it fails again, the dc source

requires service.

29