Tektronix 2440 Service Manual

Model 2440

Service Manual

2440-902-01 Rev. B / December 2004

www.keithley.com

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WARRANTY

Keithley Instruments, Inc. warrants this product to be free from defects in material and workmanship
for a period of one (1) year from date of shipment.

Keithley Instruments, Inc. warran
probes, cables, software, rechargeable batteries, diskettes, and documentation.

During the warranty period, Keithley Instruments will, at its option, ei
proves to be defective.

To exercise this warranty, write or call your local Keithley Instruments representative, or contact

thley Instruments headquarters in Cleveland, Ohio. You will be given prompt assistance and

Kei
return instructions. Send the product, transportation prepaid, to the indicated service facility. Repairs
will be made and the product returned, transportation prepaid. Repaired or replaced products are
warranted for the balance of the original warranty period, or at least 90 days.

ts the following items for 90 days from the date of shipment:

ther repair or replace any product that

LIMITATION OF WARRANTY

This warranty does not apply to defects resulting from product modification without Keithley
Instruments’ express written consent, or misuse of any product or part. This warranty also does not
apply to fuses, software, non-rechargeable batteries, damage from battery leakage, or problems
arising from normal wear or failure to follow instructions.

THIS WARRANTY IS IN LIEU OF ALL OTHER W
INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A
PARTICULAR USE. THE REMEDIES PROVIDED HEREIN ARE THE BUYER’S SOLE AND
EXCLUSIVE REMEDIES.

NEITHER KEITHLEY INSTRUMENTS, INC. NOR ANY
FOR ANY DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES

ING OUT OF THE USE OF ITS INSTRUMENTS AND SOFTWARE, EVEN IF KEITHLEY

ARIS
INSTRUMENTS, INC. HAS BEEN ADVISED IN ADVANCE OF THE POSSIBILITY OF SUCH
DAMAGES. SUCH EXCLUDED DAMAGES SHALL INCLUDE, BUT ARE NOT LIMITED TO: COST
OF REMOVAL AND INSTALLATION, LOSSES SUSTAINED AS THE RESULT OF INJURY TO ANY
PERSON, OR DAMAGE TO PROPERTY.

ARRANTIES, EXPRESSED OR IMPLIED,

OF ITS EMPLOYEES SHALL BE LIABLE

A G R E A T E R M E A S U R E O F C O N F I D E N C E

Keithley Instruments, Inc.

Corporate Headquarters • 28775 Aurora Road • Cleveland, Ohio 44139

440-248-0400 • Fax: [phone] • 1-888-KEITHLEY (1-888-534-8453) • www.keithley.com

3/07

Model 2440 5A SourceMeter

Service Manual

®

©2001, Keithley Instruments, Inc.

All rights reserved.

Cleveland, Ohio, U.S.A.

Second Printing, December 2004

Document Number: 2440-902-01 Rev. B

Manual Print History

The print history shown below lists the printing dates of all Revisions and Addenda created
for this manual. The Revision Level letter increases alphabetically as the manual undergoes sub
sequent updates. Addenda, which are released between Revisions, contain important change in­formation that the user should incorporate immediately into the manual. Addenda are numbered
sequentially. When a new Revision is created, all Addenda associated with the previous Revi
sion of the manual are incorporated into the new Revision of the manual. Each new Revision
includes a revised copy of this print history page.

Revision A (Document Number 2440-902-01)................................................................ April 2001

Revision B (Document Number 2440-902-01)........................................................Decmeber 2004

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All Keithley product names are trademarks or registered trademarks of Keithley Instruments, Inc.
Other brand names are trademarks or registered trademarks of their respective holders.

Safety Precautions

The following safety precautions should be observed before using this product and any associated instrumentation.
Although some instruments and accessories would normally be used with non-hazardous voltages, there are
situations where hazardous conditions may be present.

This product is intended for use by qualified personnel who recognize shock hazards and are familiar with the safety
precautions required to avoid possible injury. Read and follow all installation, operation, and maintenance
information carefully before using the product. Refer to the user documentation for complete product specifications.

If the product is used in a manner not specified, the protection provided by the product warranty may be impaired.
The types of product users are:
Responsible body is the individual or group responsible for the use and maintenance of equipment, for ensuring

that the equipment is operated within its specifications and operating limits, and for ensuring that operators are
adequately trained.

Operators use the product for its intended function. They must be trained in electrical safety procedures and proper
use of the instrument. They must be protected from electric shock and contact with hazardous live circuits.

Maintenance personnel perform routine procedures on the product to keep it operating properly, for example,
setting the line voltage or replacing consumable materials. Maintenance procedures are described in the user
documentation. The procedures explicitly state if the operator may perform them. Otherwise, they should be
performed only by service personnel.

Service personnel are trained to work on live circuits, perform safe installations, and repair products. Only properly
trained service personnel may perform installation and service procedures.

Keithley Instruments products are designed for use with electrical signals that are rated Measurement Category I
and Measurement Category II, as described in the International Electrotechnical Commission (IEC) Standard IEC

60664. Most measurement, control, and data I/O signals are Measurement Category I and must not be directly
connected to mains voltage or to voltage sources with high transient over-voltages. Measurement Category II
connections require protection for high transient over-voltages often associated with local AC mains connections.
Assume all measurement, control, and data I/O connections are for connection to Category I sources unless
otherwise marked or described in the user documentation.

Exercise extreme caution when a shock hazard is present. Lethal voltage may be present on cable connector jacks
or test fixtures. The American National Standards Institute (ANSI) states that a shock hazard exists when voltage
levels greater than 30V RMS, 42.4V peak, or 60VDC are present. A good safety practice is to expect that hazardous
voltage is present in any unknown circuit before measuring.

Operators of this product must be protected from electric shock at all times. The responsible body must ensure that
operators are prevented access and/or insulated from every connection point. In some cases, connections must be
exposed to potential human contact. Product operators in these circumstances must be trained to protect
themselves from the risk of electric shock. If the circuit is capable of operating at or above 1000 volts, no conductive
part of the circuit may be exposed.

Do not connect switching cards directly to unlimited power circuits. They are intended to be used with impedance­limited sources. NEVER connect switching cards directly to AC mains. When connecting sources to switching cards,
install protective devices to limit fault current and voltage to the card.

Before operating an instrument, make sure the line cord is connected to a properly grounded power recep tacle.
Inspect the connecting cables, test leads, and jumpers for possible wear, cracks, or breaks before each use.

When installing equipment where access to the main power cord is restricted, such as rack mounting, a separate
main input power disconnect device must be provided in close proximity to the equipment and within easy reach of
the operator.

04/09

For maximum safety, do not touch the product, test cables, or any other instruments while power is applied to the

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circuit under test. ALWAYS remove power from the entire test system and discharge any capacitors before:
connecting or disconnecting cables or jumpers, installing or removing switching cards, or making internal changes,
such as installing or removing jumpers.

Do not touch any object that could provide a current path to the common side of the circuit under test or power line
(earth) ground. Always make measurements with dry hands while standing on a dry, insulated surface capable of
withstanding the voltage being measured.

The instrument and accessories must be used in accordance with specifications and operating instructions, or the
safety of the equipment may be impaired.

Do not exceed the maximum signal levels of the instruments and accessories, as defined in the specifications and
operating information, and as shown on the instrument or test fixture panels, or switching card.

When fuses are used in a product, replace with the same type and rating for continued protection against fire hazard.
Chassis connections must only be used as shield connections for measuring circuits, NOT as safety earth ground

connections.
If you are using a test fixture, keep the lid closed while power is applied to the device under test. Safe operation

requires the use of a lid interlock.
If a screw is present, connect it to safety earth ground using the wire recommended in the user documentation.
The symbol on an instrument means caution, risk of danger. The user should refer to the operating instructions

located in the user documenta ti on in all case s where the symbol is marked on the instrument.
The symbol on an instrument means caution, risk of danger. User standard safety precautions to avoid

personal contact with these voltages.
The symbol on an instrument shows that the surface may be hot. Avoid personal contact to prevent burns.

The symbol indicates a connection terminal to the equipment frame.

If this symbol is on a product, it indicates that mercury is present in the display lamp. Please note that the lamp
must be properly disposed of according to federal, state, and local laws.

The WARNING heading in the user documentation explains dangers that might result in personal injury or death.
Always read the associated information very carefully before performing the indicated procedure.

The CAUTION heading in the user documentation explains hazards that could damage the instrument. Such
damage may invalidate the warranty.

Instrumentation and accessories shall not be connected to humans.
Before performing any maintenance, disconnect the line cord and all test cables.
To maintain protection from electric shock and fire, rep lacement components in mains circuits - including the power

transformer, test leads, and input jacks - must be purchased from Keithley Instruments. Standard fuses with
applicable national safety approvals may be used if the rating and type are the same. Other components that are
not safety-related may be purchased from other suppliers as long as they are equivalent to the original component
(note that selected parts should be purchased only through Keithley Instruments to maintain accuracy and
functionality of the product). If you are unsure about the applicability of a replacement component, call a Keithley
Instruments office for information.

T o clean an instrument, use a damp cloth or mild, water-based cleaner . Clean the exterior of the instrument only . Do
not apply cleaner directly to the instrument or allow liquids to enter or spill on the instrument. Products that consist
of a circuit board with no case or chassis (e.g., data acquisition board for installation into a computer) should never
require cleaning if handled according to instructions. If the board becomes contaminated and operation is affected,
the board should be returned to the factory for proper cleaning/servicing.

Table of Contents

1 Performance Verification

Introduction ................................................................................ 1-2

Verification test requirements .................................................... 1-2

Environmental conditions ................................................... 1-2

Warm-up period .................................................................. 1-3

Line power .......................................................................... 1-3

Recommended test equipment ................................................... 1-3

1Ω resistor characterization ................................................ 1-4

Verification limits ...................................................................... 1-5

Example limits calculation .................................................. 1-5

Resistance limits calculation ............................................... 1-5

Restoring factory defaults .......................................................... 1-6

Performing the verification test procedures ............................... 1-6

Test summary ...................................................................... 1-6

Test considerations ............................................................. 1-7

Setting the source range and output value .......................... 1-7

Setting the measurement range ........................................... 1-8

Compliance considerations ........................................................ 1-8

Compliance limits ............................................................... 1-8

Types of compliance ........................................................... 1-8

Maximum compliance values ............................................. 1-9

Determining compliance limit ............................................ 1-9

Taking the SourceMeter out of compliance ...................... 1-10

Output voltage accuracy ........................................................... 1-10

Voltage measurement accuracy ............................................... 1-12

Output current accuracy .................................................... 1-13

Current measurement accuracy ................................................ 1-16

Resistance measurement accuracy ........................................... 1-18

10mA to 1A range accuracy ...................................... 1-13

5A range accuracy ..................................................... 1-14

10mA to 1A range accuracy ...................................... 1-16

5A range accuracy ..................................................... 1-17

2Calibration

Introduction ................................................................................ 2-2

Environmental conditions .......................................................... 2-2

Temperature and relative humidity ..................................... 2-2

Warm-up period .................................................................. 2-2

Line power .......................................................................... 2-2

Calibration considerations .......................................................... 2-3

Calibration cycle ................................................................. 2-3

Recommended calibration equipment ................................. 2-4

1Ω resistor characterization ................................................ 2-4

Unlocking calibration ................................................................. 2-5

Unlocking calibration from the front panel ......................... 2-5

Unlocking calibration by remote ......................................... 2-6

Changing the password ............................................................... 2-7

Changing the password from the front panel ...................... 2-7

Changing the password by remote ...................................... 2-7

Resetting the calibration password ............................................. 2-8

Viewing calibration dates and calibration count ........................ 2-8

Calibration errors ........................................................................ 2-8

Front panel error reporting .................................................. 2-8

Remote error reporting ........................................................ 2-9

Front panel calibration ................................................................ 2-9

Step 1: Prepare the Model 2440 for calibration ........... 2-9

Step 2: Voltage calibration ......................................... 2-10

Step 3: Current calibration ......................................... 2-13

Step 4: Enter calibration dates and save calibration . 2-17

Step 5: Lock out calibration ...................................... 2-17

Remote calibration .................................................................... 2-18

Remote calibration commands .......................................... 2-18

Recommended calibration parameters .............................. 2-19

Remote calibration procedure ........................................... 2-20

Step 1: Prepare the Model 2440 for calibration ......... 2-20

Step 2: Voltage calibration ......................................... 2-21

Step 3: Current calibration ........................................ 2-23

Step 4: Program calibration dates .............................. 2-25

Step 5: Save calibration constants .............................. 2-25

Step 6: Lock out calibration ....................................... 2-25

Single-range calibration ............................................................ 2-25

3 Routine Maintenance

Introduction ................................................................................ 3-2

Line fuse replacement ................................................................. 3-2

4 Troubleshooting

Introduction ................................................................................ 4-2

Repair considerations ................................................................. 4-2

Power-on self-test ...................................................................... 4-2

Front panel tests ......................................................................... 4-3

KEYS test ........................................................................... 4-3

DISPLAY PATTERNS test ................................................ 4-3

CHAR SET test ................................................................... 4-4

Principles of operation ............................................................... 4-4

Overall block diagram ........................................................ 4-4

Analog circuits .................................................................... 4-4

Power supply ....................................................................... 4-7

Output stage ........................................................................ 4-8

A/D converter ..................................................................... 4-9

Active guard ........................................................................ 4-9

Digital circuitry ................................................................. 4-10

Display board circuit theory ............................................. 4-11

Troubleshooting ....................................................................... 4-12

Display board checks ........................................................ 4-12

Power supply checks ......................................................... 4-12

Digital circuitry checks ..................................................... 4-13

Analog circuitry checks .................................................... 4-14

Battery replacement ................................................................. 4-14

Battery replacement precautions ....................................... 4-15

Battery replacement procedure ......................................... 4-15

No comm link error .................................................................. 4-16

5Disassembly

Introduction ................................................................................ 5-2

Handling and cleaning ............................................................... 5-2

Handling PC boards ............................................................ 5-2

Solder repairs ...................................................................... 5-2

Static sensitive devices ............................................................... 5-3

Assembly drawings .................................................................... 5-3

Case cover removal .................................................................... 5-4

Analog board removal ................................................................ 5-5

Digital board removal ................................................................ 5-6

Front panel disassembly ............................................................. 5-6

Removing power components .................................................... 5-7

Power module removal ....................................................... 5-7

Instrument reassembly ............................................................... 5-7

6 Replaceable Parts

Introduction ................................................................................ 6-2

Parts lists ..................................................................................... 6-2

Ordering information .................................................................. 6-2

Factory service ............................................................................ 6-2

Component layouts ..................................................................... 6-3

A Specifications

B Command Reference

Introduction ............................................................................... B-2

Command summary ................................................................... B-2

Miscellaneous commands .......................................................... B-3

CODE .......................................................................... B-3

COUNT? ..................................................................... B-3

LOCK .......................................................................... B-4

SAVE .......................................................................... B-4

DATE .......................................................................... B-5

NDUE .......................................................................... B-5

SENSE ........................................................................ B-6

SOURCE ..................................................................... B-7

DATA? ........................................................................ B-9

Detecting calibration errors ....................................................... B-9

Reading the error queue ..................................................... B-9

Error summary .................................................................... B-9

Status byte EAV (Error Available) bit ............................. B-10

Generating an SRQ on error ............................................. B-10

Detecting calibration step completion ..................................... B-11

Using the *OPC? query .................................................... B-11

Using the *OPC command ............................................... B-11

Generating an SRQ on calibration complete .................... B-12

C Calibration Programs

Introduction ............................................................................... C-2

Computer hardware requirements ............................................. C-2

Software requirements ............................................................... C-2

Calibration equipment ............................................................... C-2

General program instructions .................................................... C-3

Program C-1 Model 2440 calibration program ....... C-4

Requesting calibration constants ............................................... C-7

Program C-2 Requesting calibration constants ....... C-7

List of Illustrations

1 Performance Verification

Figure 1-1 Connections for voltage verification tests ........................... 1-10

Figure 1-2 Connections for 10µA to 1A range current verification tests 1-13

Figure 1-3 Connections for 5A range current verification tests ............ 1-14

Figure 1-4 Connections for resistance accuracy verification ................ 1-18

2Calibration

Figure 2-1 Voltage calibration test connections .................................... 2-10

Figure 2-2 10µA to 1A range current calibration test connections ....... 2-13

Figure 2-3 5A range current calibration test connections ..................... 2-15

3 Routine Maintenance

Figure 3-1 Rear panel .............................................................................. 3-2

4 Troubleshooting

Figure 4-1 Overall block diagram ........................................................... 4-5

Figure 4-2 Analog circuitry block diagram ............................................. 4-6

Figure 4-3 Power supply block diagram ................................................. 4-7

Figure 4-4 Output stage simplified schematic ......................................... 4-8

Figure 4-5 Digital circuitry block diagram ............................................ 4-10

List of Tables

1 Performance Verification

Table 1-1 Recommended verification equipment .................................. 1-4

Table 1-2 Maximum compliance values ................................................ 1-9

Table 1-3 Output voltage accuracy limits ............................................. 1-11

Table 1-4 Voltage measurement accuracy limits ................................. 1-12

Table 1-5 Output current accuracy limits ............................................. 1-15

Table 1-6 Current measurement accuracy limits .................................. 1-17

Table 1-7 Ohms measurement accuracy limits ..................................... 1-19

2Calibration

Table 2-1 Recommended calibration equipment .................................... 2-4

Table 2-2 Calibration unlocked states .................................................... 2-6

Table 2-3 Front panel voltage calibration ............................................. 2-12

Table 2-4 Front panel current calibration ............................................. 2-16

Table 2-5 Remote calibration command summary ............................... 2-18

Table 2-6 Recommended :CALibration:PROTected:SENse

Table 2-7 Recommended :CALibration:PROTected:SOURce

Table 2-8 Voltage calibration initialization commands ....................... 2-22

Table 2-9 Voltage range calibration commands ................................... 2-22

Table 2-10 Current calibration initialization commands ........................ 2-24

Table 2-11 Current range calibration commands ................................... 2-24

parameter ranges .................................................................. 2-19

parameter ranges .................................................................. 2-20

3 Routine Maintenance

Table 3-1 Power line fuse ....................................................................... 3-3

4 Troubleshooting

Table 4-1 Display board checks ........................................................... 4-12

Table 4-2 Power supply checks ............................................................ 4-12

Table 4-3 Digital circuitry checks ........................................................ 4-13

Table 4-4 Analog circuitry checks ........................................................ 4-14

6 Replaceable Parts

Table 6-1 Analog board parts list ........................................................... 6-3

Table 6-2 Digital board parts list .......................................................... 6-12

Table 6-3 Display board parts list ......................................................... 6-17

Table 6-4 Miscellaneous parts list ........................................................ 6-18

B Command Reference

Table B-1 Remote calibration command summary ............................... B-2

Table B-2 Recommended :CALibration:PROTected:SENSe

parameter ranges ................................................................... B-7

Table B-3 Recommended :CALibration:PROTected:SOURce

parameter ranges ................................................................... B-8

Table B-4 Calibration errors ................................................................ B-10

1

Performance Verification

Performance Verification

1-2 Performance Verification Model 2440 5A SourceMeter® Service Manual

Introduction

Use the procedures in this section to verify that Model 2440 accuracy is within the limits
stated in the instrument’s one-year accuracy specifications. You can perform these verifi
cation procedures:

• When you first receive the instrument to make sure that it was not damaged during
shipment.

• To verify that the unit meets factory specifications.

• To determine if calibration is required.

• Following calibration to make sure it was performed properly.

WARNING The information in this section is intended for qualified service per-

sonnel only. Do not attempt these procedures unless you are qualified
to do so. Some of these procedures may expose you to hazardous volt
ages, which could cause personal injury or death if contacted. Use
standard safety precautions when working with hazardous voltages.

NOTE If the instrument is still under warranty and its performance is outside specified

limits, contact your Keithley representative or the factory to determine the cor
rect course of action.

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Verification test requirements

Be sure that you perform the verification tests:

• Under the proper environmental conditions.

• After the specified warm-up period.

• Using the correct line voltage.

• Using the proper test equipment.

• Using the specified output signals and reading limits.

Environmental conditions

Conduct your performance verification procedures in a test environment with:

• An ambient temperature of 18-28°C (65-82°F).

• A relative humidity of less than 70% unless otherwise noted.

Model 2440 5A SourceMeter® Service Manual Performance Verification 1-3

Warm-up period

Allow the Model 2440 to warm up for at least one hour before conducting the verification
procedures.

If the instrument has been subjected to temperature extremes (those outside the ranges
stated above), allow additional time for the instrument’s internal temperature to stabilize.
Typically, allow one extra hour to stabilize a unit that is 10°C (18°F) outside the specified
temperature range.

Also, allow the test equipment to warm up for the minimum time specified by the manu­facturer.

Line power

The Model 2440 requires a line voltage of 100 to 240V and a line frequency of 50 to
60Hz. Verification tests must be performed within this range.

Recommended test equipment

Table 1-1 summarizes recommended verification equipment. You can use alternate equip-

ment as long as that equipment has specifications at least as good as those listed in Table

1-1. Keep in mind, however, that test equipment uncertainty will add to the uncertainty of

each measurement. Generally, test equipment uncertainty should be at least four times bet­ter than corresponding Model 2440 specifications. Table 1-1 lists the specifications of the
recommended test equipment, including maximum allowable uncertainty for alternate test
equipment, which is shown in parentheses.

Performance Verification

1-4 Performance Verification Model 2440 5A SourceMeter® Service Manual

Table 1-1

Recommended verification equipment

Description Manufacturer/Model Specifications

Digital Multimeter Hewlett Packard

HP3458A

Resistance Calibrator Fluke 5450A Resistance** 1.9Ω:

DC Voltage* 1V:

10V:
100V:

DC Current* 10μA:

100μA:
1mA:
10mA:
100mA:
1A:

19Ω:
190Ω:

1.9kΩ:
19kΩ:
190kΩ:

1.9MΩ:
19MΩ:

±5.6ppm
±4.3ppm
±6.3ppm

±25ppm
±23ppm
±20ppm
±20ppm
±35ppm
±110ppm

±65ppm (±460ppm)
±23ppm (±280ppm)
±10.5ppm (±230ppm)
±8ppm (±200ppm)
±7.5ppm (±195ppm)
±8.5ppm (±200ppm)
±11.5ppm (±180ppm)
±30ppm (±635ppm)

Precision Resistor*** Isotec RUG-Z-1R00-0.1 1Ω, ±0.1%, 100W

* 90-day, full-range accuracy specifications of ranges required for various measurement points.

** 90-day, ±5°C specifications of nominal resistance values shown. Use actual values for tests. Maximum uncertainty of alternate

test equipment shown in parentheses.

*** Required for verification of 5A current range. Characterize resistor to ±300ppm or better using recommended DMM before ver-

ifying 5A current measurement range.

1Ω resistor characterization

The recommended 1Ω resistor should be characterized to ±300ppm or better before veri­fying the 5A current measurement range. (You need not characterize the resistor if you are
checking only the 5A current source range.) Use the 4-wire ohms function of the DMM
recommended in
value to calculate the current during the 5A current measurement range test procedure.

Table 1-1 to measure the resistance value, and then use that measured

Model 2440 5A SourceMeter® Service Manual Performance Verification 1-5

Verification limits

The verification limits stated in this section have been calculated using only the Model
2440 one-year accuracy specifications, and they do not include test equipment uncer
tainty. If a particular measurement falls outside the allowable range, recalculate new lim­its based on Model 2440 specifications and corresponding test equipment specifications.

Example limits calculation

As an example of how verification limits are calculated, assume you are testing the 10V
DC output range using a 10V output value. Using the Model 2440 10V range one-year
accuracy specification of ±(0.02% of output + 1.2mV offset), the calculated output limits
are:

Output limits = 10V ± [(10V × 0.02%) + 1.2mV]
Output limits = 10V ± (0.002 + 0.0012)
Output limits = 10V ± 3.2mV
Output limits = 9.9968V to 10.0032V

Resistance limits calculation

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Performance Verification

When verifying the resistance measurement accuracy, it will probably be necessary to
recalculate resistance limits based on the actual calibrator resistance values. You can cal
culate resistance reading limits in the same manner described above, but be sure to use the
actual calibrator resistance values and the Model 2440 normal accuracy specifications for
your calculations.

As an example, assume you are testing the 20kΩ range, and that the actual value of the
nominal 19kΩ calibrator resistor is 19.01kΩ. Using the Model 2440 20kΩ range one-year
normal accuracy specifications of ±(0.06% of reading + 3Ω), the recalculated reading
limits are:

Reading limits = 19.01kΩ ± [(19.01kΩ × 0.06%) + 3Ω]
Reading limits = 19.01kΩ ±14.4Ω
Reading limits = 18.9956kΩ to 19.0244kΩ

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1-6 Performance Verification Model 2440 5A SourceMeter® Service Manual

Restoring factory defaults

Before performing the verification procedures, restore the instrument to its factory front
panel (bench) defaults as follows:

1. Press the MENU key. The instrument will display the following prompt:

MAIN MENU

SAVESETUP COMMUNICATION CAL ©

2. Select SAVESETUP, and then press ENTER. The unit then displays:

SAVESETUP MENU

GLOBAL SOURCE-MEMORY

3. Select GLOBAL, and then press ENTER. The unit then displays:

GLOBAL SETUP MENU

SAVE RESTORE POWERON RESET

4. Select RESET, and then press ENTER. The unit displays:

RESET ORIGINAL DFLTS

BENCH GPIB

5. Select BENCH, and then press ENTER. The unit then displays:

RESETTING INSTRUMENT

ENTER to confirm; EXIT to abort

6. Press ENTER to restore bench defaults, and note the unit displays the following:

RESET COMPLETE

BENCH defaults are now restored ©
ß Press ENTER to continue

7. Press ENTER then EXIT as necessary to return to normal display.

Performing the verification test procedures

Test summary

• DC voltage output accuracy

• DC voltage measurement accuracy

• DC current output accuracy

• DC current measurement accuracy

• Resistance measurement accuracy

If the Model 2440 is not within specifications and not under warranty, see the calibration
procedures in

Section 2 for information on calibrating the unit.

Model 2440 5A SourceMeter® Service Manual Performance Verification 1-7

Test considerations

When performing the verification procedures:

• Be sure to restore factory front panel defaults as previously outlined.

• Make sure that the test equipment is properly warmed up and connected to the
Model 2440 INPUT/OUTPUT jacks. Also be sure that the front panel jacks are
selected with the TERMINALS key.

• Make sure the Model 2440 is set to the correct source range (see below).

• Be sure that the Model 2440 output is turned on before making measurements.

• Be sure the test equipment is set up for the proper function and range.

• Allow the Model 2440 output signal to settle before making a measurement.

• Do not connect test equipment to the Model 2440 through a scanner, multiplexer,
or other switching equipment.

WARNING The maximum common-mode voltage (voltage between LO and chas-

CAUTION The maximum voltage between INPUT/OUTPUT HI and LO or 4-

Performance Verification

sis ground) is 40V peak. Exceeding this value may cause a breakdown
in insulation, creating a shock hazard.

WIRE SENSE HI and LO is 42V peak. The maximum voltage between
INPUT/OUTPUT HI and 4-WIRE SENSE HI or between INPUT/
OUTPUT LO and 4-WIRE SENSE LO is 5V. Exceeding these voltage
values may result in instrument damage.

Setting the source range and output value

Before testing each verification point, you must properly set the source range and output
value as outlined below.

1. Press either the SOURCE V or SOURCE I key to select the appropriate source
function.

2. Press the EDIT key as required to select the source display field. Note that the cur­sor will flash in the source field while its value is being edited.

3. With the cursor in the source display field flashing, set the source range to the low­est possible range for the value to be sourced using the up or down RANGE key.
For example, you should use the 10V source range to output a 10V source value.
With a 10V source value and the 10V range selected, the source field display will
appear as follows:

Vsrc:+10.0000V

1-8 Performance Verification Model 2440 5A SourceMeter® Service Manual

4. With the source field cursor flashing, set the source output to the required value
using either:

• The SOURCE adjustment and left and right arrow keys.

• The numeric keys.

5. Note that the source output value will be updated immediately; you need not press
ENTER when setting the source value.

Setting the measurement range

When simultaneously sourcing and measuring either voltage or current, the measure range
is coupled to the source range, and you cannot independently control the measure range.
Thus, it is not necessary for you to set the measure range when testing voltage or current
measurement accuracy.

Compliance considerations

Compliance limits

When sourcing voltage, you can set the SourceMeter to limit current from 10nA to 5.25A.
Conversely, when sourcing current, you can set the SourceMeter to limit voltage from

0.2mV to 42V. The SourceMeter output will not exceed the programmed compliance
limit.

Types of compliance

There are two types of compliance that can occur: “real” and “range.” Depending on
which value is lower, the output will clamp at either the displayed compliance setting
(“real”) or at the maximum measurement range reading (“range”).

The “real” compliance condition can occur when the compliance setting is less than the
highest possible reading of the measurement range. When in compliance, the source out
put clamps at the displayed compliance value. For example, if the compliance voltage is
set to 1V and the measurement range is 2V, the output voltage will clamp (limit) at 1V.

“Range” compliance can occur when the compliance setting is higher than the possible
reading of the selected measurement range. When in compliance, the source output
clamps at the maximum measurement range reading (not the compliance value). For
example, if the compliance voltage is set to 1V and the measurement range is 200mV, the
output voltage will clamp (limit) at 210mV.

-

Model 2440 5A SourceMeter® Service Manual Performance Verification 1-9

Maximum compliance values

The maximum compliance values for the measurement ranges are summarized in

Table 1-2.

Table 1-2

Maximum compliance values

Maximum

Measurement

range

200mV

2V
10V
40V

10μA

100μA

1mA

10mA

100mA

1A

5A

compliance

value

210mV

2.1V

10.5V
42V

10.5μA

105μA

1.05mA

10.5mA

105mA

1.05A

5.25A

Performance Verification

When the SourceMeter goes into compliance, the “Cmpl” label or the units label (i.e.,
“mA”) for the compliance display will flash.

Determining compliance limit

The relationships to determine which compliance is in effect are summarized as follows.
They assume that the measurement function is the same as the compliance function.

• Compliance Setting < Measurement Range = Real Compliance

• Measurement Range < Compliance Setting = Range Compliance

You can determine the compliance that is in effect by comparing the displayed compli­ance setting to the present measurement range. If the compliance setting is lower than the
maximum possible reading on the present measurement range, the compliance setting is
the compliance limit. If the compliance setting is higher than the measurement range, the
maximum reading on that measurement range is the compliance limit.

1-10 Performance Verification Model 2440 5A SourceMeter® Service Manual

Taking the SourceMeter out of compliance

Verification measurements should not be made when the SourceMeter is in compliance.
For purposes of the verification tests, the SourceMeter can be taken out of compliance by
going into the edit mode and increasing the compliance limit.

NOTE Do not take the unit out of compliance by decreasing the source value or chang-

ing the range. Always use the recommended range and source settings when
performing the verification tests.

Output voltage accuracy

Follow the steps below to verify that Model 2440 output voltage accuracy is within speci­fied limits. This test involves setting the output voltage to each full-range value and mea­suring the voltages with a precision digital multimeter.

1. With the power off, connect the digital multimeter to the Model 2440 INPUT/
OUTPUT jacks, as shown in

Figure 1-1

Connections for voltage verification tests

Figure 1-1.

EDIT

DISPLAY

TOGGLE

POWER

V

LOCAL

67

DIGITS SPEED

4- WIRE

INPUT/

SENSE

OUTPUT

HI

75V

PEAK

SWEEP

SOURCE

I

5

2440 5A SourceMeter

EDIT

EXIT ENTER

MEAS

FCTN

I

Ω

230

FILTER

89

STORE

LIMIT

RECALL

V

4

TRIG

+/-

CONFIG MENU

1

REL

RANGE

AUTO

RANGE

®

ON/OFF

OUTPUT

75V

5V

PEAK

PEAK

LO

250V
PEAK

TERMINALS

FRONT/

REAR

Model 2440

Input HI

Digital Multimeter

Input LO

Model 2440 5A SourceMeter® Service Manual Performance Verification 1-11

2. Select the multimeter DC volts measuring function.

3. Set the voltage source protection to NONE. To do so, press CONFIG then
SOURCE V to access the CONFIGURE V-SOURCE menu. Select PROTEC
TION, and set the voltage source protection limit to NONE.

4. Press the Model 2440 SOURCE V key to source voltage, and make sure the source
output is turned on.

5. Verify output voltage accuracy for each of the voltages listed in Table 1-3. For
each test point:

• Select the correct source range.

• Set the Model 2440 output voltage to the indicated value.

• Verify that the multimeter reading is within the limits given in the table.

6. Repeat the procedure for negative output voltages with the same magnitudes as
those listed in

7. Repeat the entire procedure using the rear panel INPUT/OUTPUT jacks. Be sure to
select the rear panel jacks with the front panel TERMINALS key.

Table 1-3

Output voltage accuracy limits

Model 2440

source range

200mV

2V
10V
40V

Table 1-3.

Model 2440 output

voltage setting

200.000mV

2.00000V

10.0000V

40.0000V

Output voltage limits

(1 year, 18°C-28°C)

199.360 to 200.640mV

1.99900 to 2.00100V

9.9968 to 10.0032V

39.9872 to 40.0128V

Performance Verification

-

1-12 Performance Verification Model 2440 5A SourceMeter® Service Manual

Voltage measurement accuracy

Follow the steps below to verify that Model 2440 voltage measurement accuracy is within
specified limits. The test involves setting the source voltage to full-range values, as mea
sured by a precision digital multimeter, and then verifying that the Model 2440 voltage
readings are within required limits.

1. With the power off, connect the digital multimeter to the Model 2440 INPUT/
OUTPUT jacks , as shown in

2. Select the multimeter DC volts function.

3. Set the voltage source protection to NONE. To do so, press CONFIG then
SOURCE V to access the CONFIGURE V-SOURCE menu. Select PROTEC
TION, and set the voltage source protection limit to NONE.

4. Set the Model 2440 to both source and measure voltage by pressing the SOURCE
V and MEAS V keys, and make sure the source output is turned on.

5. Verify output voltage accuracy for each of the voltages listed in Table 1-4. For
each test point:

• Select the correct source range.

• Set the Model 2440 output voltage to the indicated value as measured by the
digital multimeter.

• Verify that the Model 2440 voltage reading is within the limits given in the
table.

Figure 1-1.

-

-

NOTE It may not be possible to set the voltage source to the specified value. Use the

closest possible setting, and modify reading limits accordingly.

6. Repeat the procedure for negative source voltages with the same magnitudes as
those listed in

7. Repeat the entire procedure using the rear panel INPUT/OUTPUT jacks. Be sure to
select the rear panel jacks with the front panel TERMINALS key.

Table 1-4

Voltage measurement accuracy limits

Model 2440 source

and measure

range*

200mV

2V
10V
40V

Table 1-4.

Source voltage*

200.000mV

10.0000V

40.0000V

2.00000V

Model 2440 voltage reading

limits (1 year, 18°C-28°C)

199.676 to 200.324mV

1.99946 to 2.00054V

9.9978 to 10.0022V

39.991 to 40.009V

Model 2440 5A SourceMeter® Service Manual Performance Verification 1-13

Table 1-4

Voltage measurement accuracy limits

Model 2440 source

and measure

range* Source voltage*

* Measure range coupled to source range when simultaneously sourcing and measuring voltage.

** As measured by precision digital multimeter. Use closest possible value, and modify reading lim-

its accordingly if necessary.

Output current accuracy

Follow the steps below to verify that Model 2440 output current accuracy is within speci­fied limits. The test involves setting the output current to each full-range value and mea­suring the currents with a precision digital multimeter.

10μA to 1A range accuracy

1. With the power off, connect the digital multimeter to the Model 2440 INPUT/
OUTPUT jacks, as shown in

Figure 1-2

Connections for 10μA to 1A range current verification tests

V

LOCAL

67

DIGITS SPEED

MEAS

I

Ω

1

230

REL

FILTER

89

RECALL

STORE

EDIT

DISPLAY

TOGGLE

POWER

Performance Verification

Model 2440 voltage reading

limits (1 year, 18°C-28°C)

Figure 1-2.

4- WIRE

INPUT/

SENSE

OUTPUT

HI

75V

PEAK

RANGE

AUTO

RANGE

®

2440 5A SourceMeter

V

4

TRIG

SWEEP

+/-

CONFIG MENU

I

5

SOURCE

EDIT

EXIT ENTER

FCTN

LIMIT

ON/OFF

OUTPUT

75V

5V

PEAK

PEAK

LO

250V
PEAK

TERMINALS

FRONT/

REAR

Model 2440

Digital Multimeter

2. Select the multimeter DC current measuring function.

Input LO

Amps

1-14 Performance Verification Model 2440 5A SourceMeter® Service Manual

3. Press the Model 2440 SOURCE I key to source current, and make sure the source
output is turned on.

4. Verify output current accuracy for the 10μA-1A range currents listed in Table 1-5.
For each test point:

• Select the correct source range.

• Set the Model 2440 output current to the correct value.

• Verify that the multimeter reading is within the limits given in the table.

5. Repeat the procedure for negative output currents with the same magnitudes as
those listed in

Table 1-5.

6. Repeat the entire procedure using the rear panel INPUT/OUTPUT jacks. Be sure to
select the rear panel jacks with the front panel TERMINALS key.

5A range accuracy

1. With the power off, connect the digital multimeter and the 1Ω resistor to the Model
2440 INPUT/OUTPUT jacks, as shown in

Figure 1-3

Connections for 5A range current verification tests

SWEEP

I

5

SOURCE

2440 5A SourceMeter

EDIT

EXIT ENTER

RANGE

AUTO

RANGE

EDIT

DISPLAY

TOGGLE

POWER

V

LOCAL

67

DIGITS SPEED

MEAS

FCTN

I

Ω

230

FILTER

89

STORE

LIMIT

RECALL

V

4

TRIG

+/-

CONFIG MENU

1

REL

4- WIRE

SENSE

HI

75V

5V

PEAK

PEAK

®

LO

ON/OFF

OUTPUT

INPUT/

OUTPUT

TERMINALS

FRONT/

REAR

Figure 1-3.

75V
PEAK

250V
PEAK

Model 2440

Digital Multimeter

1Ω Resistor

Input HI

Input LO

Model 2440 5A SourceMeter® Service Manual Performance Verification 1-15

2. Select the multimeter DC volts measuring function.

3. Press the Model 2440 SOURCE I key to source current, and make sure the source
output is turned on.

4. Verify output current accuracy for the 5A range. Be sure to:

• Select the 5A source range.

• Set the Model 2440 output current to the correct 5A output value.

• Verify that the multimeter reading is within the 5A range limits given in Table

1-5.

(Since the value of the 1Ω resistor value is assumed to be the same as its nominal
value, the DMM voltage reading is the same as the sourced current.)

5. Repeat the procedure for a negative 5A current output value.

6. Repeat the entire procedure using the rear panel INPUT/OUTPUT jacks. Be sure to
select the rear panel jacks with the front panel TERMINALS key.

Table 1-5

Output current accuracy limits

Model 2440

source range

10μA

100μA

1mA

10mA

100mA

1A
5A*

Model 2440

output current setting

10.0000μA

100.000μA

1.00000mA

10.0000mA

100.000mA

1.00000A

5.00000A

Output current limits

(1 year, 18°C-28°C)

9.9947 to 10.0053μA

99.949 to 100.051μA

0.99946 to 1.00054mA

9.9935 to 10.0065mA

99.914 to 100.086mA

0.99843 to 1.00157A

4.9896 to 5.0104A

Performance Verification

*See separate procedure for 5A range. DMM voltage reading is same as sourced current.

1-16 Performance Verification Model 2440 5A SourceMeter® Service Manual

Current measurement accuracy

Follow the steps below to verify that Model 2440 current measurement accuracy is within
specified limits. The procedure involves applying accurate currents from the Model 2440
current source and then verifying that Model 2440 current measurements are within
required limits.

10μA to 1A range accuracy

1. With the power off, connect the digital multimeter to the Model 2440 INPUT/
OUTPUT jacks, as shown in

2. Select the multimeter DC current function.

3. Set the Model 2440 to both source and measure current by pressing the SOURCE I
and MEAS I keys, and make sure the source output is turned on.

4. Verify measure current accuracy for the 10μA-1A range currents listed in Table

1-6. For each measurement:

• Select the correct source range.

• Set the Model 2440 source output to the correct value as measured by the dig­ital multimeter.

• Verify that the Model 2440 current reading is within the limits given in the
table.

Figure 1-2.

NOTE It may not be possible to set the current source to the specified value. Use the

closest possible setting, and modify reading limits accordingly.

5. Repeat the procedure for negative calibrator currents with the same magnitudes as
those listed in

6. Repeat the entire procedure using the rear panel INPUT/OUTPUT jacks. Be sure to
select the rear panel jacks with the front panel TERMINALS key.

Table 1-6.

Model 2440 5A SourceMeter® Service Manual Performance Verification 1-17

5A range accuracy

NOTE The 1Ω resistor should be characterized to within ±300ppm before verifying the

5A current measurement range. Use the 4-wire ohms function of the DMM to
measure the resistance value, and then use that measured value to calculate the
current during the measurement procedure.

1. With the power off, connect the 1Ω resistor and digital multimeter to the Model
2440 INPUT/OUTPUT jacks, as shown in

2. Select the multimeter DC volts function.

3. Set the Model 2440 to both source and measure current by pressing the SOURCE I
and MEAS I keys, and make sure the source output is turned on.

4. Verify measurement current accuracy for the 5A range as follows:

• Select the 5A source range.

• Set the Model 2440 source output to the correct 5A value as measured by the
digital multimeter.

• Note the DMM voltage reading, and then calculate the current from the volt­age reading and characterized 1Ω resistance value as I = V/R, where V is the
DMM voltage reading and R is the characterized resistance value.

• Verify that the Model 2440 current reading is within the 5A limits given in the

Table 1-6.

NOTE It may not be possible to set the current source to the specified 5A value. Use the

closest possible setting, and modify reading limits accordingly.

Figure 1-3.

Performance Verification

5. Repeat the procedure for a negative 5A current.

6. Repeat the procedure using the rear panel INPUT/OUTPUT jacks. Be sure to select
the rear panel jacks with the front panel TERMINALS key.

Table 1-6

Current measurement accuracy limits

Model 2440 source

and measure range*

10μA

100μA

1mA

10mA

100mA

1A
5A

*Measure range coupled to source range when simultaneously sourcing and measuring current.

** As measured by precision digital multimeter. Use closest possible value, and modify reading limits

accordingly if necessary.

*** Current calculated as follows: I = V/R, where V is the DMM voltage reading, and R is the character-

ized value of the 1Ω resistor.

Source current**

10.00000μA

100.000μA

1.00000mA

10.0000mA

100.000mA

1.00000A

5.00000A

Model 2440 current reading limits

(1 year, 18°C-28°C)

9.9966 to 10.0034μA

99.969 to 100.031μA

0.99967 to 1.00033mA

9.9959 to 10.0041mA

99.939 to 100.061mA

0.99883 to 1.00117A

4.9916 to 5.0084A***

1-18 Performance Verification Model 2440 5A SourceMeter® Service Manual

Resistance measurement accuracy

Use the following steps to verify that Model 2440 resistance measurement accuracy is
within specified limits. This procedure involves applying accurate resistances from a
resistance calibrator and then verifying that Model 2440 resistance measurements are
within required limits.

CAUTION Before testing the 2Ω and 20Ω ranges make sure your resistance cali-

brator can safely handle the default test currents for those ranges (see
Model 2440 and calibrator specifications). If not, use the CONFIG
OHMS menu to select the MANUAL source mode, then set the source
current to an appropriate safe value. When using the manual source
mode, total resistance reading uncertainty includes both Source I and
Measure V uncertainty (see specifications), and calculated reading
limits should take the additional uncertainty into account.

If using the Fluke 5450A resistance calibrator, you cannot use the
Auto Ohms mode of the Model 2440 to verify the 2Ω range. The 1A
test current for the 2Ω range of the Model 2440 will damage the cali
brator. On the Model 2440, use the CONFIG OHMS menu to select
the MANUAL source mode, and then set the source (test) current to
100mA.

-

1. With the power off, connect the resistance calibrator to the Model 2440 INPUT/
OUTPUT and 4-WIRE SENSE jacks, as shown in
4-wire connections as shown.

Figure 1-4. Be sure to use the

Model 2440 5A SourceMeter® Service Manual Performance Verification 1-19

Figure 1-4

Connections for resistance accuracy verification

4- WIRE

INPUT/

SENSE

OUTPUT

HI

EDIT

DISPLAY

TOGGLE

POWER

V

LOCAL

67

DIGITS SPEED

75V

PEAK

SWEEP

I

5

SOURCE

2440 5A SourceMeter

EDIT

EXIT ENTER

MEAS

FCTN

I

Ω

230

FILTER

89

STORE

LIMIT

RECALL

V

4

TRIG

+/-

CONFIG MENU

1

REL

RANGE

AUTO

RANGE

®

Model 2440

Resistance Calibrator

ON/OFF

OUTPUT

75V

5V

PEAK

PEAK

LO

250V
PEAK

TERMINALS

FRONT/

REAR

Output HI Sense HI

Output LO

Sense LO

2. Select the resistance calibrator external sense mode.

3. Configure the Model 2440 ohms function for the 4-wire sense mode as follows:

• Press CONFIG then MEAS Ω. The instrument will display the following:

CONFIG OHMS

SOURCE SENSE-MODE GUARD

• Select SENSE-MODE, and then press ENTER. The following will be
displayed:

SENSE-MODE

2-WIRE 4-WIRE

• Select 4-WIRE, and then press ENTER.

• Press EXIT to return to normal display.

4. Press MEAS Ω to select the ohms measurement function, and make sure the source
output is turned on.

5. Verify ohms measurement accuracy for each of the resistance values listed in Table

1-7. For each measurement:

• Set the resistance calibrator output to the nominal resistance or closest avail­able value.

NOTE It may not be possible to set the resistance calibrator to the specified value. Use

the closest possible setting, and modify reading limits accordingly.

• Select the appropriate ohms measurement range with the RANGE keys.

Performance Verification

1-20 Performance Verification Model 2440 5A SourceMeter® Service Manual

• Verify that the Model 2440 resistance reading is within the limits given in the
table.

6. Repeat the entire procedure using the rear panel INPUT/OUTPUT and 4-WIRE
SENSE jacks. Be sure to select the rear panel jacks with the front panel TERMI

-

NALS key.

Table 1-7

Ohms measurement accuracy limits

Calibrator

Model 2440 range

2Ω

20Ω

200Ω

2kΩ

20kΩ

200kΩ

2MΩ

20MΩ

* Nominal resistance value.

** Reading limits based on Model 2440 normal accuracy specifications and nominal resistance values. If

actual resistance values differ from nominal values shown, recalculate reading limits using actual calibra
tor resistance values and Model 2440 normal accuracy specifications. See Verification limits earlier in this
section for details.

resistance*

1.9Ω

19Ω

190Ω

1.9kΩ

19kΩ

190kΩ

1.9MΩ

19MΩ

Model 2440 resistance reading limits**

(1 year, 18°C-28°C)

1.89647 to 1.90353Ω

18.9780 to 19.0220Ω

189.818 to 190.182Ω

1.89837 to 1.90163kΩ

18.9856 to 19.0144kΩ

189.837 to 190.163kΩ

1.89761 to 1.90239MΩ

18.9781 to 19.0219MΩ

-

2

Calibration

Calibration

2-2 Calibration Model 2440 5A SourceMeter® Service Manual

Introduction

Use the procedures in this section to calibrate the Model 2440. These procedures require
accurate test equipment to measure precise DC voltages and currents. Calibration can be
performed either from the front panel or by sending SCPI calibration commands over the
IEEE-488 bus or RS-232 port with the aid of a computer.

WARNING This information in this section is intended for qualified service per-

sonnel only. Do not attempt these procedures unless you are qualified
to do so. Some of these procedures may expose you to hazardous volt
ages.

Environmental conditions

Temperature and relative humidity

Conduct the calibration procedures at an ambient temperature of 18-28°C (65-82°F) with
relative humidity of less than 70% unless otherwise noted.

-

Warm-up period

Allow the Model 2440 to warm up for at least one hour before performing calibration.

If the instrument has been subjected to temperature extremes (those outside the ranges
stated above), allow additional time for the instrument’s internal temperature to stabilize.
Typically, allow one extra hour to stabilize a unit that is 10°C (18°F) outside the specified
temperature range.

Also, allow the test equipment to warm up for the minimum time specified by the
manufacturer.

Line power

The Model 2440 requires a line voltage of 100 to 240V at line frequency of 50 to 60Hz.
The instrument must be calibrated while operating from a line voltage within this range.

Model 2440 5A SourceMeter® Service Manual Calibration 2-3

Calibration considerations

When performing the calibration procedures:

• Make sure that the test equipment is properly warmed up and connected to the
Model 2440 front panel INPUT/OUTPUT jacks. Also be certain that the front
panel jacks are selected with the TERMINALS switch.

• Always allow the source signal to settle before calibrating each point.

• Do not connect test equipment to the Model 2440 through a scanner or other
switching equipment.

• If an error occurs during calibration, the Model 2440 will generate an appropriate
error message. See

Appendix B for more information.

WARNING The maximum common-mode voltage (voltage between LO and chas-

CAUTION The maximum voltage between INPUT/OUTPUT HI and LO or

Calibration cycle

Perform calibration at least once a year to ensure the unit meets or exceeds its
specifications.

NOTE Calibration constants are stored in volatile memories of the Model 2440, which

are protected by a replaceable battery when power is off. Typical life for the
battery is approximately 10 years, but the battery should be replaced if the volt
age drops below 2.5V regardless of age. See Section 4 for battery replacement
details.

Calibration

sis ground) is 40V peak. Exceeding this value may cause a breakdown
in insulation, creating a shock hazard.

4-WIRE SENSE HI and LO is 42V peak. The maximum voltage
between INPUT/OUTPUT HI and 4-WIRE SENSE HI or between
INPUT/OUTPUT LO and 4-WIRE SENSE LO is 5V. Exceeding these
voltage values may result in instrument damage.

-

2-4 Calibration Model 2440 5A SourceMeter® Service Manual

Recommended calibration equipment

Table 2-1 lists the recommended equipment for the calibration procedures. You can use

alternate equipment as long that equipment has specifications at least as good as those
listed in the table. For optimum calibration accuracy, test equipment specifications should
be at least four times better than corresponding Model 2440 specifications.

Table 2-1

Recommended calibration equipment

Description Manufacturer/Model Specifications

Digital Multimeter Hewlett Packard

HP3458A

Precision Resistor** Isotec RUG-Z-1R00-0.1 1Ω, ±0.1%, 100W

* 90-day, full-range accuracy specifications of ranges required for various measurement points.

** Necessary for calibration of 5A current range. Resistor must be characterized to ±300ppm or better using recommended DMM

before calibrating 5A range.

DC Voltage*

DC Current*

1V:
10V:
100V

10μA:
100μA:
1mA:
10mA:
100mA:
1A:

±5.6ppm
±4.3ppm
±6.3ppm

±25ppm
±23ppm
±20ppm
±20ppm
±35ppm
±110ppm

1Ω resistor characterization

The 1Ω resistor must be characterized to ±300ppm or better before calibrating the 5A cur­rent range. Use the 4-wire ohms function of the DMM recommended in Table 2-1 to mea­sure the resistance value, and then use that measured value to calculate the current during
the 5A current range calibration procedure.

Model 2440 5A SourceMeter® Service Manual Calibration 2-5

Unlocking calibration

Before performing calibration, you must first unlock calibration by entering or sending the
calibration password as explained in the following paragraphs.

Unlocking calibration from the front panel

1. Press the MENU key, and then choose CAL, and press ENTER. The instrument
will display the following:

CALIBRATION

UNLOCK EXECUTE VIEW-DATES

ß SAVE LOCK CHANGE-PASSWORD

2. Select UNLOCK, and then press ENTER. The instrument will display the
following:

PASSWORD:

Use ß, ©, ¹, ƒ, ENTER or EXIT.

3. Use the up and down RANGE keys to select the letter or number, and use the left
and right arrow keys to choose the position. (Press down RANGE for letters; up
RANGE for numbers.) Enter the present password on the display. (Front panel
default: 002440.)

4. Once the correct password is displayed, press the ENTER key. If the password was
correctly entered, the following message will be displayed:

CALIBRATION UNLOCKED

Calibration can now be executed.

5. Press EXIT to return to normal display. Calibration will be unlocked and assume
the states summarized in
below with calibration unlocked will result in an error +510, “Not permitted with
cal unlocked.”

Table 2-2. Attempts to change any of the settings listed

Calibration

NOTE With calibration unlocked, the sense function and range track the source func-

tion and range. That is, when :SOUR:FUNC is set to VOLT, the :SENS:FUNC
setting will be 'VOLT:DC'. When :SOUR:FUNC is set to CURR, the
:SENS:FUNC setting will be 'CURR:DC'. A similar command coupling exists
for :SOUR:VOLT:RANG/:SENS:VOLT:RANG and
SOUR:CURR:RANG:SENS:CURR:RANG.

2-6 Calibration Model 2440 5A SourceMeter® Service Manual

Table 2-2

Calibration unlocked states

Mode State Equivalent remote command

Concurrent Functions
Sense Function
Sense Volts NPLC
Sense Volts Range
Sense Current NPLC
Sense Current Range
Filter Count
Filter Control
Filter Averaging
Source V Mode
Volts Autorange
Source I Mode
Current Autorange
Autozero
Trigger Arm Count
Trigger Arm Source
Trigger Count
Trigger Source

OFF
Source

1.0
Source V

1.0
Source I
10
REPEAT
ON
FIXED
OFF
FIXED
OFF
ON
1
Immediate
1
Immediate

Unlocking calibration by remote

To unlock calibration via remote, send the following command:

:CAL:PROT:CODE '<password>'

:SENS:FUNC:CONC OFF
:SENS:FUNC <source_ function>
:SENS:VOLT:NPLC 1.0
:SENS:VOLT:RANG <source_V_range>
:SENS:CURR:NPLC 1.0
:SENS:CURR:RANG <source_ I_ range>
:SENS:AVER:COUN 10
:SENS:AVER:TCON REPeat
:SENS:AVER:STAT ON
:SOUR:VOLT:MODE FIXED
:SOUR:VOLT:RANG:AUTO OFF
:SOUR:CURR:MODE FIXED
:SOUR:CURR:RANG:AUTO OFF
:SYST:AZERO ON
:ARM:COUNT 1
:ARM:SOUR IMMediate
:TRIG:COUNT 1
:TRIG:SOUR IMMediate

For example, the following command uses the default password:

:CAL:PROT:CODE 'KI002440'

Model 2440 5A SourceMeter® Service Manual Calibration 2-7

Changing the password

The default password may be changed from the front panel or via remote as discussed
below.

Changing the password from the front panel

Follow the steps below to change the password from the front panel:

1. Press the MENU key, then choose CAL and press ENTER. The instrument will
display the following:

CALIBRATION

UNLOCK EXECUTE VIEW-DATES ©

ß SAVE LOCK CHANGE-PASSWORD

2. Select UNLOCK, then enter the password. (Default: 002440.)

3. Select CHANGE-PASSWORD, and then press ENTER. The instrument will dis­play the following:

New Pwd: 002440

Use ß, ©, ¹, ƒ, ENTER or EXIT.

4. Using the range keys, and the left and right arrow keys, enter the new password on
the display.

5. Once the desired password is displayed, press the ENTER key to store the new
password.

Calibration

Changing the password by remote

To change the calibration password by remote, first send the present password, and then
send the new password. For example, the following command sequence changes the pass
word from the 'KI002440' remote default to 'KI_CAL':

:CAL:PROT:CODE 'KI002440'
:CAL:PROT:CODE 'KI_CAL'

You can use any combination of letters and numbers up to a maximum of eight characters.

NOTE If you change the first two characters of the password to something other than

“KI”, you will not be able to unlock calibration from the front panel.

-

2-8 Calibration Model 2440 5A SourceMeter® Service Manual

Resetting the calibration password

If you lose the calibration password, you can unlock calibration by shorting together the
CAL pads, which are located on the display board. Doing so will also reset the password
to the factory default (KI002440).

See Section 5 for details on disassembling the unit to access the CAL pads. Refer to the
display board component layout drawing at the end of Section 6 for the location of the
CAL pads.

Viewing calibration dates and calibration count

When calibration is locked, only the UNLOCK and VIEW-DATES selections will be
accessible in the calibration menu. To view calibration dates and calibration count at any
time:

1. From normal display, press MENU, select CAL, and then press ENTER. The unit
will display the following:

CALIBRATION

UNLOCK EXECUTE VIEW-DATES

2. Select VIEW-DATES, and then press ENTER. The Model 2440 will display the
next and last calibration dates and the calibration count as in the following
example:

NEXT CAL: 02/15/2002

Last calibration: 02/15/2001 Count: 0001

Calibration errors

The Model 2440 checks for errors after each calibration step, minimizing the possibility
that improper calibration may occur due to operator error.

Front panel error reporting

If an error is detected during comprehensive calibration, the instrument will display an
appropriate error message (see
calibration step that caused the error.

Appendix B). The unit will then prompt you to repeat the

Model 2440 5A SourceMeter® Service Manual Calibration 2-9

Remote error reporting

You can detect errors while in remote by testing the state of EAV (Error Available) bit (bit

2) in the status byte. (Use the *STB? query to request the status byte.) Query the instru
ment for the type of error by using the appropriate :SYST:ERR? query. The Model 2440
will respond with the error number and a text message describing the nature of the error.
See

Appendix B for details.

-

Front panel calibration

The front panel calibration procedure described below calibrates all ranges of both the
current and voltage source and measure functions. Note that each range is separately cali
brated by repeating the entire procedure for each range.

Step 1: Prepare the Model 2440 for calibration

1. Turn on the Model 2440 and the digital multimeter, and allow them to warm up for
at least one hour before performing calibration.

2. Press the MENU key, then choose CAL and press ENTER. Select UNLOCK, and
then press ENTER. The instrument will display the following:

PASSWORD:

Use ß, ©, ¹, ƒ, ENTER or EXIT.

3. Use the up and down range keys to select the letter or number, and use the left and
right arrow keys to choose the position. Enter the present password on the display.
(Front panel default: 002440.) Press ENTER to complete the process.

4. Press EXIT to return to normal display. Instrument operating states will be set as
summarized in Table 2-2.

-

Calibration

2-10 Calibration Model 2440 5A SourceMeter® Service Manual

Step 2: Voltage calibration

Perform the steps below for each voltage range, using Table 2-3 as a guide.

1. Connect the Model 2440 to the digital multimeter, as shown in Figure 2-1. Select
the multimeter DC volts measurement function.

NOTE The 2-wire connections shown assume that remote sensing is not used. Remote

sensing may be used, if desired, but it is not essential when using the recom
mended digital multimeter.

Figure 2-1

Voltage calibration test connections

SWEEP

I

5

SOURCE

2440 5A SourceMeter

EDIT

EXIT ENTER

EDIT

DISPLAY

TOGGLE

POWER

V

LOCAL

67

DIGITS SPEED

MEAS

FCTN

I

Ω

230

FILTER

89

STORE

LIMIT

RECALL

V

4

TRIG

+/-

CONFIG MENU

1

REL

RANGE

AUTO

RANGE

4- WIRE

INPUT/

SENSE

OUTPUT

HI

75V

PEAK

®

ON/OFF

OUTPUT

75V

5V

PEAK

PEAK

LO

250V
PEAK

TERMINALS

FRONT/

REAR

-

Model 2440

Input HI

Digital Multimeter

Input LO

2. From normal display, press the SOURCE V key.

3. Press the EDIT key to select the source field (cursor flashing in source display
field), and then use the down RANGE key to select the 200mV source range.

4. From normal display, press MENU.

5. Select CAL, and then press ENTER. The unit will display the following:

CALIBRATION

UNLOCK EXECUTE VIEW-DATES ©

ß SAVE LOCK CHANGE-PASSWORD

Model 2440 5A SourceMeter® Service Manual Calibration 2-11

6. Select EXECUTE, and then press ENTER. The instrument will display the follow­ing message:

V-CAL

Press ENTER to Output +200.00mV

7. Press ENTER. The Model 2440 will source +200mV and simultaneously display
the following:

DMM RDG: +200.0000mV

Use ß, ©, ¹, ƒ, ENTER, or EXIT.

8. Note and record the DMM reading, and then adjust the Model 2440 display to
agree exactly with the actual DMM reading. Use the up and down arrow keys to
select the digit value, and use the left and right arrow keys to choose the digit posi
tion (or use the number keys, 0-9, +/-). Note that the display adjustment range is
within ±10% of the present range.

9. After adjusting the display to agree with the DMM reading, press ENTER. The
instrument will then display the following:

V-CAL
Press ENTER to Output +000.00mV

10. Press ENTER. The Model 2440 will source 0mV and at the same time display the
following:

DMM RDG: +000.0000mV

Use ß, ©, ¹, ƒ, ENTER, or EXIT.

11. Note and record the DMM reading, and then adjust the Model 2440 display to
agree with the actual DMM reading. Note that the display value adjustment limits
are within ±1% of the present range.

12. After adjusting the display value to agree with the DMM reading, press ENTER.
The unit will then display the following:

V-CAL

Press ENTER to Output -200.00mV

13. Press ENTER. The Model 2440 will source -200mV and display the following:

DMM RDG: -200.0000mV

Use ß, ©, ¹, ƒ, ENTER, or EXIT.

14. Note and record the DMM reading, and then adjust the Model 2440 display to
agree with the DMM reading. Again, the maximum display adjustment is within ±
10% of the present range.

15. After adjusting the display value to agree with the DMM reading, press ENTER
and note that the instrument displays:

V-CAL

Press ENTER to Output -000.00mV

16. Press ENTER The Model 2440 will source -0mV and simultaneously display the
following:

DMM RDG: +000.0000mV

Use ß, ©, ¹, ƒ, ENTER or EXIT.

-

Calibration

2-12 Calibration Model 2440 5A SourceMeter® Service Manual

17. Note and record the DMM reading, and then adjust the display to agree with the
DMM reading. Once again, the maximum adjustment is within ±1% of the present
range.

18. After adjusting the display to agree with the DMM reading, press ENTER to com­plete calibration of the present range.

19. Press EXIT to return to normal display, and then select the 2V source range.
Repeat steps 2 through 18 for the 2V range.

20. After calibrating the 2V range, repeat the entire procedure for the 10V and 40V
ranges using

Table 2-3 as a guide. Be sure to select the appropriate source range

with the EDIT and RANGE keys before calibrating each range.

21. Press EXIT as necessary to return to normal display.

Table 2-3

Front panel voltage calibration

Source
range*

Source voltage

0.2V +200.00mV
+000.00mV

-200.00mV

-000.00mV

2V +2.0000V

+0.0000V

-2.0000V

-0.0000V

10V +10.000V

+00.000V

-10.000V

-00.000V

40V +40.000V

+00.000V

-40.000V

-00.000V

**Use EDIT and RANGE keys to select source range.

**Multimeter reading used in corresponding calibration step. See procedure.

Multimeter

voltage reading**

___________ mV
___________ mV
___________ mV
___________ mV

___________ V
___________ V
___________ V
___________ V

___________ V
___________ V
___________ V
___________ V

___________ V
___________ V
___________ V
___________ V

Model 2440 5A SourceMeter® Service Manual Calibration 2-13

Step 3: Current calibration

Perform the steps below for each current range, using Table 2-4 as a guide.

1. Connect the Model 2440 to the digital multimeter, as shown in Figure 2-2. Select
the multimeter DC current measurement function.

Figure 2-2

10μA to 1A range current calibration test connections

4- WIRE

INPUT/

SENSE

OUTPUT

HI

EDIT

DISPLAY

TOGGLE

POWER

V

LOCAL

67

DIGITS SPEED

75V

PEAK

SWEEP

I

5

SOURCE

2440 5A SourceMeter

EDIT

EXIT ENTER

MEAS

FCTN

I

Ω

230

FILTER

89

STORE

LIMIT

RECALL

V

4

TRIG

+/-

CONFIG MENU

1

REL

RANGE

AUTO

RANGE

®

Model 2440

ON/OFF

OUTPUT

75V

5V

PEAK

PEAK

LO

250V
PEAK

TERMINALS

FRONT/

REAR

Input LO

Calibration

Digital Multimeter

Amps

2. From normal display, press the SOURCE I key.

3. Press the EDIT key to select the source display field, and then use the down
RANGE key to select the 10μA source range.

4. From normal display, press MENU.

5. Select CAL, and then press ENTER. The unit will display the following:

CALIBRATION

UNLOCK EXECUTE VIEW-DATES ©

ß SAVE LOCK CHANGE-PASSWORD

6. Select EXECUTE, and then press ENTER. The instrument will display the follow­ing message:

I-CAL

Press ENTER to Output +10.000μA

2-14 Calibration Model 2440 5A SourceMeter® Service Manual

7. Press ENTER. The Model 2440 will source +10μA and simultaneously display the
following:

DMM RDG: +10.00000μA
Use ß, ©, ¹, ƒ, ENTER, or EXIT.

8. Note and record the DMM reading, and then adjust the Model 2440 display to
agree exactly with the actual DMM reading. Use the up and down arrow keys to
select the digit value, and use the left and right arrow keys to choose the digit posi
tion (or use the number keys, 0-9, +/-). Note that the display adjustment range is
within ±10% of the present range.

9. After adjusting the display to agree with the DMM reading, press ENTER. The
instrument will then display the following:

I-CAL

Press ENTER to Output +00.000μA

10. Press ENTER. The Model 2440 will source 0mA and at the same time display the
following:

DMM RDG: +00.00000μA

Use ß, ©, ¹, ƒ, ENTER, or EXIT.

11. Note and record the DMM reading, and then adjust the Model 2440 display to
agree with the actual DMM reading. Note that the display value adjustment limits
are within ±1% of the present range.

12. After adjusting the display value to agree with the DMM reading, press ENTER.
The unit will then display the following:

I-CAL

Press ENTER to Output -10.000μA

13. Press ENTER. The Model 2440 will source -10μA and display the following:

DMM RDG: -10.00000μA

Use ß, ©, ¹, ƒ, ENTER, or EXIT.

14. Note and record the DMM reading, and then adjust the Model 2440 display to
agree with the DMM reading. Again, the maximum display adjustment is within
±10% of the present range.

15. After adjusting the display value to agree with the DMM reading, press ENTER
and note that the instrument displays:

I-CAL

Press ENTER to Output -00.000μA

16. Press ENTER The Model 2440 will source -0μA and simultaneously display the
following:

DMM RDG: +00.00000μA

Use ß, ©, ¹, ƒ, ENTER, or EXIT.

17. Note and record the DMM reading, and then adjust the display to agree with the
DMM reading. Once again, the maximum adjustment is within ±1% of the present
range.

-

Model 2440 5A SourceMeter® Service Manual Calibration 2-15

18. After adjusting the display to agree with the DMM reading, press ENTER to com­plete calibration of the present range.

19. Press EXIT to return to normal display, and then select the 100μA source range use
the EDIT and up RANGE keys. Repeat steps 2 through 18 for the 100μA range.

20. After calibrating the 100μA range, repeat the entire procedure for the 1mA through
1A ranges using

Table 2-4 as a guide. Be sure to select the appropriate source

range with the EDIT and up RANGE keys before calibrating each range.

21. After calibrating the 1A range, connect the 1Ω characterized resistor and DMM to
the Model 2440 INPUT/OUTPUT jacks, as shown in

Figure 2-3.

22. Select the DMM DC volts function.

23. Repeat steps 2 through 18 for the 5A range using Table 2-4 as a guide. When enter­ing the DMM reading, use the calculated current as follows: I = V/R, where V is
the DMM voltage reading, and R is the characterized value of the 1Ω resistor.

Figure 2-3

5A range current calibration test connections

4- WIRE

INPUT/

SENSE

OUTPUT

HI

EDIT

DISPLAY

TOGGLE

POWER

V

LOCAL

67

DIGITS SPEED

75V

PEAK

SWEEP

I

5

SOURCE

2440 5A SourceMeter

EDIT

EXIT ENTER

MEAS

FCTN

I

Ω

230

FILTER

89

RECALL

STORE

V

4

TRIG

LIMIT

+/-

CONFIG MENU

1

REL

RANGE

AUTO

RANGE

®

ON/OFF

OUTPUT

75V

5V

PEAK

PEAK

LO

250V
PEAK

TERMINALS

FRONT/

REAR

Calibration

Model 2440

Digital Multimeter

1Ω Resistor

Input HI

Input LO

2-16 Calibration Model 2440 5A SourceMeter® Service Manual

Table 2-4

Front panel current calibration

Multimeter

Source range* Source current

current reading**

10μA +10.000μA

+00.000μA

-10.000μA

-00.000μA

100μA +100.00μA

+000.00μA

-100.00μA

-000.00μA

1mA +1.0000mA

+0.0000mA

-1.0000mA

-0.0000mA

10mA +10.000mA

+00.000mA

-10.000mA

-00.000mA

100mA +100.00mA

+000.00mA

-100.00mA

-000.00mA

1A +1.0000A

+0.0000A

-1.0000A

-0.0000A

___________ μA
___________ μA
___________ μA
___________ μA

___________ μA
___________ μA
___________ μA
___________ μA

___________ mA
___________ mA
___________ mA
___________ mA

___________ mA
___________ mA
___________ mA
___________ mA

___________ mA
___________ mA
___________ mA
___________ mA

___________ A
___________ A
___________ A
___________ A

5A*** +5.0000A

+0.0000A

-5.0000A

-0.0000A

*Use EDIT and RANGE keys to select source range.

**Multimeter reading used in corresponding calibration step. See procedure.

***Current calculated as follows: I = V/R, where V is the DMM reading, and R is the

characterized value of the 1Ω resistor.

___________ A
___________ A
___________ A
___________ A

Model 2440 5A SourceMeter® Service Manual Calibration 2-17

Step 4: Enter calibration dates and save calibration

NOTE For temporary calibration without saving new calibration constants, proceed to

“Step 5: Lock out calibration”.

1. From normal display, press MENU.

2. Select CAL, and then press ENTER. The Model 2440 will display the following:

CALIBRATION

UNLOCK EXECUTE VIEW-DATES ©

ß SAVE LOCK CHANGE-PASSWORD

3. Select SAVE, and then press ENTER. The instrument will display the following
message:

SAVE CAL
Press ENTER to continue; EXIT to abort calibration sequence.

4. Press ENTER. The unit will prompt you for the calibration date:

CAL DATE: 2/15/2001

Use ß, ©, ¹, ƒ, ENTER, or EXIT.

5. Change the displayed date to today's date, and then press the ENTER key. Press
ENTER again to confirm the date.

6. The unit will then prompt for the calibration due date:

NEXT CAL: 2/15/2002

Use ß, ©, ¹, ƒ, ENTER, or EXIT.

7. Set the calibration due date to the desired value, and then press ENTER. Press
ENTER again to confirm the date.

8. Once the calibration dates are entered, calibration is complete, and the following
message will be displayed:

CALIBRATION COMPLETE

Press ENTER to confirm; EXIT to abort

9. Press ENTER to save the calibration data (or press EXIT to abort without saving
calibration data.) The following message will be displayed:

CALIBRATION SUCCESS

Press ENTER or EXIT to continue.

10. Press ENTER or EXIT to complete process.

Calibration

Step 5: Lock out calibration

1. From normal display, press MENU.

2. Select CAL, and then press ENTER. The Model 2440 will display the following:

CALIBRATION

UNLOCK EXECUTE VIEW-DATES ©

ß SAVE LOCK CHANGE-PASSWORD

3. Select LOCK, and then press ENTER. The instrument will display the following
message:

CALIBRATION LOCKED.

Press ENTER or EXIT to continue.

4. Press ENTER or EXIT to return to normal display.

2-18 Calibration Model 2440 5A SourceMeter® Service Manual

Remote calibration

Use the following procedure to perform remote calibration by sending SCPI commands
over the IEEE-488 bus or RS-232 port. The remote commands and appropriate parameters
are separately summarized for each step.

Remote calibration commands

Table 2-5 summarizes remote calibration commands. For a more complete description of

these commands, refer to Appendix B.

Table 2-5

Remote calibration command summary

Command Description

:CALibration

:PROTected

:CODE '<password>'

:COUNT?
:SAVE
:LOCK
:LOCK?
:DATE <y>,<m>,<d>
:DATE?
:NDUE <y>,<m>,<d>
:NDUE?
:SENSe <nrf>

:DATA?

:SOURce <nrf>

:DATA?

* Calibration data will not be saved if:

1. Calibration was not unlocked with :CODE command.

2. Invalid data exists. (For example, cal step failed or was aborted.)

3. Incomplete number of cal steps were performed. (For example, omitting a negative full-scale step).
Ranges that calibrated successfully will be saved if calibration is unlocked. Ranges that failed will not be
saved.

Calibration subsystem.
Cal commands protected by password.
Unlock cal; changes password if cal is already unlocked.

(Default password: KI002440.)
Query number of times 2440 has been calibrated.
Save calibration data to EEPROM.*
Lock calibration, inhibit SAVE command operation.
Request cal lock status.
Program calibration year, month, day.
Query calibration year, month, day.
Program calibration due year, month, day.
Query calibration due year, month, day.
Calibrate active measure range. (See Table 2-6 parameters.)
Query measurement cal constants for active range.
Calibrate active source range. (See Table 2-7 parameters.)
Query source cal constants for active range.

Model 2440 5A SourceMeter® Service Manual Calibration 2-19

Recommended calibration parameters

The maximum calibration command parameter ranges are: 75% to 150% of full scale for
positive and negative full scale calibration points; ± zero calibration steps have ±50% of
full scale for valid entry ranges. However, for optimum calibration, it is recommended that
you use calibration points within the ranges listed in
each sense range requires three parameters: zero, negative full scale, and positive full
scale. Similarly, each source range requires four parameters: two zero parameters, a posi
tive full-scale parameter, and a negative full-scale parameter.

Table 2-6

Recommended :CALibration:PROTected:SENse parameter ranges

Table 2-6 and Table 2-7. Note that

-

Sense
range

0.2V
2V
10V
40V

10μA
100μA
1mA
10mA
100mA
1A
5A

Note: Parameter steps for each range may be performed in any order, but all three parameter steps for each

range must be completed. For optimum calibration, use parameters within recommended limits.

First parameter

(zero)

-0.002 to +0.002

-0.02 to +0.02

-0.1 to +0.1

-0.5 to +0.5

-1E-7 to +1E-7

-1E-6 to +1E-6

-1E-5 to +1E-5

-1E-4 to +1E-4

-1E-3 to +1E-3

-1E-2 to +1E-2

-5E-2 to +5E-2

Second parameter

(negative full scale)

-0.18 to -0.22

-1.8 to -2.2

-9 to -11

-35 to -42

-9E-6 to -11E-6

-90E-6 to -110E-6

-0.9E-3 to -1.1E-3

-9E-3 to -11E-3

-90E-3 to -110E-3

-0.9 to -1.1

-4.75 to -5.25

Third parameter

(positive full scale)

+0.18 to +0.22

+1.8 to +2.2

+9 to +11

+35 to +42

+9E-6 to +11E-6

+90E-6 to +110E-6

+0.9E-3 to +1.1E-3

+9E-3 to +11E-3

+90E-3 to +110E-3

+0.9 to +1.1

+4.75 to +5.25

Calibration

2-20 Calibration Model 2440 5A SourceMeter® Service Manual

Table 2-7

Recommended :CALibration:PROTected:SOURce parameter ranges

Second parameter

Source range

0.2V
2V
10V
40V

10μA
100μA
1mA
10mA
100mA
1A
5A

Note: Parameter steps for each range may be performed in any order, but all four parameter steps for each range must be completed.

For optimum calibration, use parameters within recommended limits.

(negative full scale)

-0.18 to -0.22

-1.8 to -2.2

-9 to -11

-35 to -42

-9E-6 to -11E-6

-90E-6 to -110E-6

-0.9E-3 to -1.1E-3

-9E-3 to -1E-3

-90E-3 to -110E-3

-0.9 to -1.1

-4.75 to -5.25

Second parameter

(negative zero)

-0.002 to +0.002

-0.02 to +0.02

-0.1 to +0.1

-0.5 to +0.5

-1E-7 to +1E-7

-1E-6 to +1E-6

-1E-5 to +1E-5

-1E-4 to +1E-4

-1E-3 to +1E-3

-1E-2 to +1E-2

-5E-2 to +5E-2

Third parameter

(positive full scale)

+0.18 to +0.22

+1.8 to +2.2

+9 to +11

+35 to +42

+9E-6 to +11E-6

+90E-6 to +110E-6

+0.9E-3 to +1.1E-3

+9E-3 to +11E-3

+90E-3 to +110E-3

+0.9 to +1.1

+4.75 to +5.25

Fourth parameter

(positive zero)

-0.002 to +0.002

-0.02 to +0.02

-0.1 to +0.1

-0.5 to +0.5

-1E-7 to +1E-7

-1E-6 to +1E-6

-1E-5 to +1E-5

-1E-4 to +1E-4

-1E-3 to +1E-3

-1E-2 to +1E-2

-5E-2 to +5E-2

Remote calibration procedure

Step 1: Prepare the Model 2440 for calibration

1. Connect the Model 2440 to the controller IEEE-488 interface or RS-232 port using
a shielded interface cable.

2. Turn on the Model 2440 and the test equipment, and allow them to warm up for at
least one hour before performing calibration.

3. If you are using the IEEE-488 interface, make sure the primary address of the
Model 2440 is the same as the address specified in the program you will be using
to send commands. (Use the MENU key and the COMMUNICATION menu to
access the IEEE-488 address.)

Model 2440 5A SourceMeter® Service Manual Calibration 2-21

Step 2: Voltage calibration

1. Connect the Model 2440 to the digital multimeter (see Figure 2-1), and select the
multimeter DC volts function.

2. Send the commands summarized in Table 2-8 in the order listed to initialize volt­age calibration. (When the :CAL:PROT:CODE command is sent, the instrument
will assume the operating states listed in

3. Perform the range calibration steps listed in Table 2-9 for all ranges. For each
range:

• Send the :SOUR:VOLT:RANG command to select the source and sense range
being calibrated. For example, for the 2V range, the following command
would be sent:

:SOUR:VOLT:RANG 2

• Program the source to output the negative full-range value using the
:SOUR:VOLT command. For example:

:SOUR:VOLT -2

• Note and record the multimeter reading.

• Use the multimeter reading as the parameter for the :CAL:PROT:SOUR and

• :CAL:PROT:SENS commands. For example, a typical value for the 2V range
would be:

:CAL:PROT:SOUR -1.998
:CAL:PROT:SENS -1.998

• Program the voltage source for 0V output using the :SOUR:VOLT 0.0
command.

• Note the multimeter reading.

• Send the source and sense calibration commands using the multimeter reading
for the parameter. For example:

:CAL:PROT:SOUR 1E-3
:CAL:PROT:SENS 1E-3

• Set the source to the positive full-range value using the :SOUR:VOLT com­mand. For example:

:SOUR:VOLT 2

• Note and record the multimeter reading.

• Send the source and sense commands using the multimeter reading as the
parameter. For example:

:CAL:PROT:SOUR 1.997
:CAL:PROT:SENS 1.997

• Send the SOUR:VOLT 0.0 command to set the source voltage to 0V.

• Note and record the multimeter reading.

• Send the :CAL:PROT:SOUR command using the multimeter reading as the
command parameter. For example:

:CAL:PROT:SOUR -1.02E-3

Table 2-2.)

Calibration

2-22 Calibration Model 2440 5A SourceMeter® Service Manual

Table 2-8

Voltage calibration initialization commands

Command Description

*RST
:SOUR:FUNC VOLT
:SENS:CURR:PROT 0.1
:SENS:CURR:RANG 0.1
:SOUR:VOLT:PROT MAX
:SYST:RSEN OFF
:CAL:PROT:CODE 'KI002440'
:OUTP:STAT ON

*Remote sensing may be used if desired, but is not essential when using the recommended digital

multimeter. To use remote sensing, send :SYST:RSEN ON.

Restore GPIB defaults.
Activate voltage source.
Current limit when voltage source is active.
Make sure 1A range is not active.
Maximum allowable source voltage.
Disable remote sensing.*
Unlock cal.
Turn source on.

Table 2-9

Voltage range calibration commands

Step Command/procedure* Description

1

:SOUR:VOLT:RANGE <Range>

2

:SOUR:VOLT -<Source_value>

3

Take DMM reading.

4

:CAL:PROT:SOUR <DMM_Reading>

5

Check 2440 for errors.

6

:CAL:PROT:SENS <DMM_Reading>

7

Check 2440 for errors.

8

:SOUR:VOLT 0.0

9

Take DMM reading.

10

:CAL:PROT:SOUR <DMM_Reading>

11

Check 2440 for errors.

12

:CAL:PROT:SENS <DMM_Reading>

13

Check 2440 for errors.

14

:SOUR:VOLT +<Source_value>

15

Take DMM reading.

16

:CAL:PROT:SOUR <DMM_Reading>

17

Check 2440 for errors.

18

:CAL:PROT:SENS <DMM_Reading>

19

Check 2440 for errors.

20

:SOUR:VOLT 0.0

21

Take DMM reading.

22

:CAL:PROT:SOUR <DMM_Reading>

*1. Perform complete procedure for each range, where <Range> = 0.2, 2, 10, and 40, and <Source_value> = 0.2, 2, 10, and 40.

2. <DMM_Reading> parameter is multimeter reading from previous step.

3. Use :SYST:ERR? query to check for errors.

Select source range.
Establish negative full-range polarity.
Read actual output value.
Calibrate sense function negative full scale.

Calibrate source function negative full scale.

Set output to 0V.
Read actual output value.
Calibrate sense function negative zero.

Calibration source function negative zero.

Establish positive full-range polarity.
Read actual output value
Calibrate sense function positive full scale.

Calibrate source function positive full scale.

Set output to 0V.
Read actual output value.
Calibrate source positive zero.

Model 2440 5A SourceMeter® Service Manual Calibration 2-23

Step 3: Current calibration

1. Connect the Model 2440 to the digital multimeter (see Figure 2-2), and select the
multimeter DC current function.

2. Send the commands summarized in Table 2-10 in the order listed to initialize cur-
rent calibration.

3. Calibrate the 10μA to 1A current ranges using the procedure summarized in Table

2-11. For each range:

• Send the :SOUR:CURR:RANG command to select the source and sense range
being calibrated. For example, for the 1mA range, the command is:

:SOUR:CURR:RANG 1E-3

• Program the source to output the negative full-range value using the

:SOUR:CURR command. For example:

:SOUR:CURR -1E-3

• Note and record the multimeter reading.

• Use the multimeter reading as the parameter for the :CAL:PROT:SOUR and
:CAL:PROT:SENS commands. For example, a typical value for the 1mA
range would be:

:CAL:PROT:SOUR -1.025E-3
:CAL:PROT:SENS -1.025E-3

• Program the current source for 0A output using the :SOUR:CURR 0.0
command.

• Note the multimeter reading.

• Send the source and sense calibration commands using the multimeter reading
for the parameter. For example:

:CAL:PROT:SOUR 1E-6
:CAL:PROT:SENS 1E-6

• Set the source to the positive full-range value using the :SOUR:CURR com­mand. For example, for the 1mA range:

:SOUR:CURR 1E-3

• Note and record the multimeter reading.

• Send the source and sense commands using the multimeter reading as the
parameter. For example:

:CAL:PROT:SOUR 1.03E-3
:CAL:PROT:SENS 1.03E-3

• Send the :SOUR:CURR 0.0 command to set the source current to 0A.

• Note and record the multimeter reading.

• Send the :CAL:PROT:SOUR command using the multimeter reading as the
command parameter. For example:

:CAL:PROT:SOUR 1E-6

Calibration

2-24 Calibration Model 2440 5A SourceMeter® Service Manual

4. Connect the 1Ω resistor and DMM to the Model 2440 INPUT/OUPUT jacks, as
shown in

Figure 2-3. Select the DMM DC volts function.

5. Repeat step 3 for the 5A range using the calculated current as follows: I = V/R,
where V is the DMM voltage reading, and R is the characterized value of the 1Ω
resistor.

Table 2-10

Current calibration initialization commands

Command Description

:SOUR:FUNC CURR
:SENS:VOLT:PROT 10
:SENS:VOLT:RANG 10
:OUTP:STAT ON

Select source current mode.
Voltage limit when current source is active.
Make sure 40V range is not active.
Turn source on.

Table 2-11

Current range calibration commands

Step Command/procedure* Description

1
2
3
4
5
6
7
8

9
10
11
12
13
14
15
16
17
18
19
20
21
22

*1. Perform complete procedure for each range, where <Range> and <Source_value> = 10E-6, 100E-6, 1E-3,

10E-3, 100E-3, 1, or 5.

2. <DMM_Reading> parameter is multimeter reading from previous step.

3. Use :SYST:ERR? query to check for errors.

:SOUR:CURR:RANGE <Range>
:SOUR:CURR -<Source_value>
Take DMM reading.
:CAL:PROT:SOUR <DMM_Reading>
Check 2440 for errors.
:CAL:PROT:SENS <DMM_Reading>
Check 2440 for errors.
:SOUR:CURR 0.0
Take DMM reading.
:CAL:PROT:SOUR <DMM_Reading>
Check 2440 for errors.
:CAL:PROT:SENS <DMM_Reading>
Check 2440 for errors.
:SOUR:CURR +<Source_value>
Take DMM reading.
:CAL:PROT:SOUR <DMM_Reading>
Check 2440 for errors.
:CAL:PROT:SENS <DMM_Reading>
Check 2440 for errors.
:SOUR:CURR 0.0
Take DMM reading.
:CAL:PROT:SOUR <DMM_Reading>

Select source range.
Establish negative full-range polarity.
Read actual output value.
Calibrate sense function negative full scale.

Calibrate source function negative full scale.

Set output to 0A.
Read actual output value.
Calibrate sense function negative zero.

Calibration source function negative zero.

Establish positive full-range polarity.
Read actual output value.
Calibrate sense function positive full scale.

Calibrate source function positive full scale.

Set output to 0A.
Read actual output value.
Calibrate source positive zero.

Model 2440 5A SourceMeter® Service Manual Calibration 2-25

Step 4: Program calibration dates

Use following commands to set the calibration date and calibration due date:

:CAL:PROT:DATE <year>, <month>, <day> (Calibration date)
:CAL:PROT:NDUE <year>, <month>, <day> (Next calibration due date)

Note that the year, month, and date must be separated by commas.

Step 5: Save calibration constants

Calibration is now complete, so you can store the calibration constants in EEROM by
sending the following command:

:CAL:PROT:SAVE

NOTE Calibration will be temporary unless you send the SAVE command. Also, cali-

bration data will not be saved if (1) calibration is locked, (2) invalid data exists,
or (3) all steps were not completed.

Step 6: Lock out calibration

To lock out further calibration, send the following command after completing the calibra­tion procedure:

Calibration

:CAL:PROT:LOCK

Single-range calibration

Normally, the complete calibration procedure should be performed to ensure that the
entire instrument is properly calibrated. In some instances, however, you may want to cal
ibrate only certain ranges. To do so, complete the entire procedure only for the range(s) to
be calibrated. Keep in mind, however, that you must complete all parameter steps for each
source or sense range. Also be sure to set calibration dates and save calibration after cali
brating the desired range(s).

-

-

2-26 Calibration Model 2440 5A SourceMeter® Service Manual

3

Routine Maintenance

Routine Maintenance

3-2 Routine Maintenance Model 2440 5A SourceMeter® Service Manual

CAUTION:FOR CONTINUED PROTECTION AGAINST FIRE HAZARD,REPLACE FUSE WITH SAME TYPE AND RATING.

CAUTION:FOR CONTINUED PROTECTION AGAINST FIRE HAZARD,REPLACE FUSE WITH SAME TYPE AND RATING.

WARNING: NO INTERNAL OPERATOR SERVICABLE PARTS, SERVICE BY QUALIFIED PERSONNEL ONLY.

Introduction

The information in this section deals with routine type maintenance that can be performed
by the operator.

Line fuse replacement

WARNING Disconnect the line cord at the rear panel, and remove all test leads

connected to the instrument (front and rear) before replacing the line
fuse.

The power line fuse is accessible from the rear panel, just above the AC power receptacle
(see

Figure 3-1).

Figure 3-1

Rear panel

42V

PEAK

4-WIRE
SENSE

WITH FRONT PANEL MENU)

HI

5V

PEAK

LO

INPUT/

!

OUTPUT

IEEE-488

(ENTER IEEE ADDRESS

5V
PK

42V

PEAK

40V

PEAK

5V

PEAK

V, Ω,

GUARD

GUARD

SENSE

CATI

RS232

Model 2440

TRIGGER

LINK

MADE IN

U.S.A.

LINE FUSE

SLOWBLOW

3.15A, 250V

LINE RATING

100-240VAC

50, 60HZ

220VA MAX

OUTPUT
ENABLE

Model 2440 5A SourceMeter® Service Manual Routine Maintenance 3-3

Perform the following steps to replace the line fuse:

1. Carefully grasp and squeeze together the locking tabs that secure the fuse carrier to
the fuse holder.

2. Pull out the fuse carrier, and replace the fuse with the type specified in Table 3-1.

CAUTION To prevent instrument damage, use only the fuse type specified in

Table 3-1.

3. Reinstall the fuse carrier.

NOTE If the power line fuse continues to blow, a circuit malfunction exists and must be

corrected. Refer to the troubleshooting section of this manual for additional
information.

Table 3-1

Power line fuse

Line voltage Rating Keithley part no.

100-240V 250V, 3.15A, Slow

Blow 5 × 20mm

FU-106-3.15

Routine Maintenance

3-4 Routine Maintenance Model 2440 5A SourceMeter® Service Manual

4

Troubleshooting

Troubleshooting

4-2 Troubleshooting Model 2440 5A SourceMeter® Service Manual

Introduction

This section of the manual will assist you in troubleshooting and repairing the Model

2440. Included are self-tests, test procedures, troubleshooting tables, and circuit descrip
tions. Note that disassembly instructions are located in Section 5, and component layout
drawings are at the end of Section 6.

WARNING The information in this section is intended for qualified service per-

sonnel only. Do not perform these procedures unless you are qualified
to do so. Some of these procedures may expose you to hazardous volt
ages that could cause personal injury or death. Use caution when
working with hazardous voltages.

-

Repair considerations

Before making any repairs to the Model 2440, be sure to read the following
considerations.

CAUTION The PC-boards are built using surface mount techniques and require

specialized equipment and skills for repair. If you are not equipped
and/or qualified, it is strongly recommended that you send the unit
back to the factory for repairs or limit repairs to the PC-board
replacement level. Without proper equipment and training, you could
damage a PC-board beyond repair.

• Repairs will require various degrees of disassembly. However, it is

recommended that the Front Panel Tests be performed prior to
any disassembly. The disassembly instructions for the Model 2440
are contained in

• Do not make repairs to surface mount PC-boards unless equipped

and qualified to do so (see previous CAUTION).

• When working inside the unit and replacing parts, be sure to

adhere to the handling precautions and cleaning procedures
explained in

• Many CMOS devices are installed in the Model 2440. These static-

sensitive devices require special handling as explained in

Section 5.

• Whenever a circuit board is removed or a component is replaced,

the Model 2440 must be recalibrated. See
calibrating the unit.

Section 5 of this manual.

Section 5.

Section 2 for details on

-

Model 2440 5A SourceMeter® Service Manual Troubleshooting 4-3

Power-on self-test

During the power-on sequence, the Model 2440 will perform a checksum test on its
EPROM and test its RAM. If one of these tests fails, the instrument will lock up.

Front panel tests

There are three front panel tests: one to test the functionality of the front panel keys and
two to test the display. In the event of a test failure, refer to
details on troubleshooting the display board.

KEYS test

The KEYS test lets you check the functionality of each front panel key. Perform the fol­lowing steps to run the KEYS test.

1. Display the MAIN MENU by pressing the MENU key.

2. Select TEST, and press ENTER to display the SELF-TEST MENU.

3. Select DISPLAY-TESTS, and press ENTER to display the following menu:

FRONT PANEL TESTS

KEYS DISPLAY-PATTERNS CHAR-SET

4. Select KEYS, and press ENTER to start the test. When a key is pressed, the label
name for that key will be displayed to indicate that it is functioning properly. When
the key is released, the message “No keys pressed” is displayed.

5. Pressing EXIT tests the EXIT key. However, the second consecutive press of EXIT
aborts the test and returns the instrument to the SELF-TEST MENU. Continue
pressing EXIT to back out of the menu structure.

“Display board checks” for

DISPLAY PATTERNS test

The display test lets you verify that each pixel and annunciator in the vacuum fluorescent
display is working properly. Perform the following steps to run the display test:

1. Display the MAIN MENU by pressing the MENU key.

2. Select TEST, and press ENTER to display the SELF-TEST MENU.

3. Select DISPLAY-TESTS, and press ENTER to display the following menu:

FRONT PANEL TESTS

KEYS DISPLAY-PATTERNS CHAR-SET

4. Select DISPLAY-PATTERNS, and press ENTER to start the display test. There
are five parts to the display test. Each time a front panel key (except EXIT) is
pressed, the next part of the test sequence is selected. The five parts of the test
sequence are as follows:

• Checkerboard pattern (alternate pixels on) and all annunciators.

• Checkerboard pattern and the annunciators that are on during normal
operation.

• Horizontal lines (pixels) of the first digit are sequenced.

Troubleshooting

4-4 Troubleshooting Model 2440 5A SourceMeter® Service Manual

• Vertical lines (pixels) of the first digit are sequenced.

• Each digit (and adjacent annunciator) is sequenced. All the pixels of the
selected digit are on.

5. When finished, abort the display test by pressing EXIT. The instrument returns to
the FRONT PANEL TESTS MENU. Continue pressing EXIT to back out of the
menu structure.

CHAR SET test

The character set test lets you display all characters. Perform the following steps to run the
character set test:

1. Display the MAIN MENU by pressing the MENU key.

2. Select TEST, and press ENTER to display the SELF-TEST MENU.

3. Select DISPLAY-TESTS, and press ENTER to display the following menu:

FRONT PANEL TESTS

KEYS DISPLAY-PATTERNS CHAR-SET

4. Select CHAR-SET, and press ENTER to start the character set test. Press any key
except EXIT to cycle through all displayable characters.

5. When finished, abort the character set test by pressing EXIT. The instrument
returns to the FRONT PANEL TESTS MENU. Continue pressing EXIT to back
out of the menu structure.

Principles of operation

The following information is provided to support the troubleshooting tests and procedures
covered in this section of the manual. Refer to the following drawings:

Figure 4-1 — Overall block diagram
Figure 4-2 — Analog circuitry block diagram
Figure 4-3 — Power supply block diagram
Figure 4-4 — Output stage simplified schematic
Figure 4-5 — Digital circuitry block diagram

Overall block diagram

Figure 4-1 shows an overall block diagram of the Model 2440. Circuitry may be divided

into three general areas:

• Analog circuits — includes sourcing circuits such as the DACs, clamps, output
stage, and feedback circuits, as well as measurement circuits such as the A/D
converter.

• Digital circuits — includes the microcomputer that controls the analog section,
front panel, and GPIB and RS-232 ports, as well as associated interfacing circuits.

Model 2440 5A SourceMeter® Service Manual Troubleshooting 4-5

• Power supplies — converts the AC line voltage into DC voltages that supply the
power for the digital and analog circuits, and the output stage.

Analog circuits

Figure 4-2 shows the analog circuitry block.

Troubleshooting

4-6 Troubleshooting Model 2440 5A SourceMeter® Service Manual

Figure 4-1

Overall block diagram

Analog Section

Display,

Keyboard

Digital

I/O

Trigger

Link

Front

Panel

Controller

Trigger,

Digital

I/O

DACs

Clamps

Feedback

A/D

Converter

Microcomputer

Digital Section

Output

Stage

RS-232

GPIB

Interface

Guard
Buffer

Output

Guard

RS-232 I/O

GPIB I/O

To Analog

Circuits

±15V

+5V ±21V

Analog

Power

Supply

To

Output Stage

±58V +5V +12V

Output

Stage

Power

Supply

Line In

Power Supply

To

Digital Circuits

Digital

Power

Supply

Model 2440 5A SourceMeter® Service Manual Troubleshooting 4-7

Figure 4-2

Analog circuitry block diagram

V DAC

I DAC

Control

Stage

+21

+58

+

-

Sense

Resistors

Protection

Protection

O

Output

HI

S+

Output

LO

S-

Guard

Out

Guard

Sense

FB

VFB

A/D

IFB

V Clamp

I Clamp

+7

MUX

-21

-58

Error
Amp

VFB

IFB

S

Output

O

Remote

O

D/A converters control the programmed voltage and current, or voltage compliance and
current compliance. Each DAC has two ranges, a 10V full-scale output or a 1V full-scale
output. The DAC outputs are fed to the summing node, FB. Either the V DAC or the
I

DAC has the ability to control the main loop. If the unit is set for SV (source voltage), it
will source voltage until the compliance current is reached (as determined by the I DAC
setting), and the current loop will override the voltage loop. If, however, the unit is set for
SI (source current), it will source current until the compliance voltage is reached (as deter
mined by the V DAC setting), and the voltage loop will override the current loop. A prior­ity bit in the V clamp/I clamp circuit controls these functions.

-

The error amplifier adds open-loop gain and slew-rate control to the system to assure
accuracy and provide a controllable signal for the output stage, which provides the neces
sary voltage and current gain to drive the output. Sense resistors in the HI output lead pro­vide output current sensing, and a separate sense resistor is used for each current range.
The 1A and 5A ranges use 0.2V full-scale for a full-range output, while all other ranges
use 2V output for full-scale current. Voltage feedback is routed either internally or exter
nally.

There are four voltage ranges: 0.2V, 2V, 10V, and 40V. The feedback gain changes only
for the 10V and 40V ranges, resulting in three unique feedback gain values. A multiplexer
directs the voltage feedback, current feedback, reference, or ground signal to the A/D con
verter. An opto-isolated interface provides control signals for both DACs, analog circuit
control, and A/D converter communication to the digital section.

-

Troubleshooting

-

-

4-8 Troubleshooting Model 2440 5A SourceMeter® Service Manual

Power supply

Figure 4-3 shows a block diagram of the Model 2440 power delivery system.

Figure 4-3

Power supply block diagram

Line
Neutral

Analog Board

+15V +5V

FF F

Constant Frequency

Low Noise Floating

Switching Supply

D

PFC

+24Vdc

DC/DC

Converter

F

-15V

+24dc

Regulators

D

Output Stage

-58V -21V +21V +58V

+12Vdc

DC

+5Vdc

O

Digital

Circuits

D

The offline switching power supply provides all power for the instrument while providing
universal inputs and power factor correction for the 110/120V line. The digital board runs
off of 5V and 12V supplies derived from the switcher. The +12VD supply is set to pro

-

gram the flash ROM. (See Digital circuitry below.)

A constant-frequency switching supply runs off the +24VD supplies and generates all the
floating and output supply voltages for the analog board: +5V and ±15V, ±21V and ±58V.

Model 2440 5A SourceMeter® Service Manual Troubleshooting 4-9

Output stage

Figure 4-4 shows a simplified schematic of the output stage.

Figure 4-4

Output stage simplified schematic

+58V

HI Drive

Q500

+21V

Q504

Q514

Maindrive

O

+15V

300K

-15V

F

F

F

+

-

HI Drive

Q516

Q518

F

Q521

F

Q523

Q525

Troubleshooting

Q507

-21V

Q503

-58V

4-10 Troubleshooting Model 2440 5A SourceMeter® Service Manual

The Model 2440 output stage serves two purposes: (1) it converts signals from floating
common to output common, and (2) it provides both voltage and current amplification.
The output stage drive transistors are biased in class B configuration to prevent the possi
bility of thermal runaway with high-current output values.

Output transistors Q518 and Q521 are cascoded with output MOSFETs Q516 and Q523.
All other MOSFETs and transistors are slaves, and the voltages across these devices are
determined by the resistor-capacitor ladder circuits shown. High-current drive capability
is provided by Q500-Q511. Coarse current limits are built into the output stage.

A/D converter

The SourceMeter unit uses a multi-slope charge balance A/D converter with a single-slope
run-down. The converter is controlled by gate array U610. Commands are issued by the
MPU on the digital board through communications opto-isolators to U610, and U610
sends A/D reading data back through opto-isolators to the digital board for calibration and
processing.

Active guard

The Model 2440 has an active guard or “six-wire ohms” circuit used to measure complex
devices. This circuitry provides a low-current (50mA) equivalent of the voltage on output
HI. If the unit is in the SV mode, the low-current equivalent of the source voltage will
appear on the guard terminal. If the unit is in the SI mode, the voltage on output HI is
equal to the source current multiplied by the external resistance value. An equivalent volt
age will be generated by the guard circuit, and a guard sense terminal is provided to sense
around the voltage drop in the guard leads since significant current can flow (50mA).

-

-

Model 2440 5A SourceMeter® Service Manual Troubleshooting 4-11

Digital circuitry

Refer to Figure 4-5 for the following discussion on digital circuitry.

The core digital circuitry uses a Motorola 68332 microcontroller running at 16.78MHz.
The memory configuration includes two 256K X 8-bit flash EEPROMs and two 128K X
8-bit RAMs used in parallel to utilize the 16-bit data bus of the MPU. The RAM is battery
backed-up, providing continued storage of data buffer information during power-down
cycles, and flash ROM support allows internal firmware upgrades using either the serial or
GPIB port for downloading new firmware. All calibration constants and the save 0 setup
are stored in a separate serial EEPROM. Setups 1 through 4 are stored in battery backed­up RAM.

External communication is provided via GPIB and serial interfaces. A 9914 GPIB
IEEE-488 standard interface IC is used for the GPIB, and a 68332 Queued Serial Module
(QSM) provides the serial UART. For internal communications, the Time Processing Unit
(TPU) is used for serial communications with the front panel display module, and both the
TPU and QSM handle digital-to-analog interfacing.

Figure 4-5

Digital circuitry block diagram

A/D

Control/Data

Reset

2

E PROM

U17

A/D Interface

U9, U25

Voltage Source

Control

ROM

U15, U16

Microprocessor

U3

RAM

U12, U14

16.78MHz

Serial

Interface

U4

GPIB

U6, U13

U20

Trigger

Digital I/O

U23

U7

RS-232 Interface

IEEE-488 Interface

To Display

Board Controller

Trigger

Digital

I/O

Troubleshooting

4-12 Troubleshooting Model 2440 5A SourceMeter® Service Manual

Display board circuit theory

U902 is the display microcontroller that controls the VFD (vacuum fluorescent display)
and interprets key data. The microcontroller has four peripheral I/O ports that are used for
the various control and read functions.

Display data is serially transmitted to the microcontroller from the digital board via the
TXB line to the microcontroller PD0 terminal. In a similar manner, key data is serially
sent back to the digital board through the RXB line via PD1. The 4MHz clock for the
microcontroller is generated on the digital board.

DS901 is the VFD (vacuum fluorescent display) module, which can display up to 49 char­acters. Each character is organized as a 5 × 7 matrix of dots or pixels and includes a long
under-bar segment to act as a cursor.

The display uses a common multiplexing scheme with each character refreshed in
sequence. U903 and U904 are the grid drivers, and U901 and U905 are the dot drivers.
Note that dot driver and grid driver data is serially transmitted from the microcontroller
(PD3 and PC1).

The front panel keys (S901-S931) are organized into a row-column matrix to minimize the
number of microcontroller peripheral lines required to read the keyboard. A key is read by
strobing the columns and reading all rows for each strobed column. Key down data is
interpreted by the display microcontroller and sent back to the main microprocessor using
proprietary encoding schemes.

Model 2440 5A SourceMeter® Service Manual Troubleshooting 4-13

Troubleshooting

Troubleshooting information for the various circuits is summarized below.

Display board checks

If the front panel display tests indicate that there is a problem on the display board, use

Table 4-1. See “Principles of operation” for display circuit theory.

Table 4-1

Display board checks

Step Item/component Required condition Remarks

1

Front panel test

2

J1033

3

U902, pin 1

4

U902, pin 43

5

U902, pin32

6

U902, pine 33

Verify that all segments
operate.
+5V, ±5%
Goes low briefly on power
up, and then goes high.
4MHz square wave.
Pulse train every 1 ms.
Brief pulse train when front
panel key is pressed.

Use front panel display test.

Digital +5V supply.
Microcontroller RESET.

Controller 4MHz clock.
Control from main processor.
Key down data sent to main
processor.

Power supply checks

Power supply problems can be checked out using Table 4-2. See “Principles of operation”
for circuit theory on the power supply.

Table 4-2

Power supply checks

Step Item/component Required condition Remarks

1

Line fuse

2

Line power

3

TP502

4

TP503

5

TP504

6

TP505

7

TP507

8

TP508

9

TP510

Check continuity.
Plugged into live receptacle,
power on.
+58V, ±10%

-58V, ±10%
+21V, ±10%

-21V, ±10%
+15V, ±5%

-15V, ±5%
+5V, ±5%

Troubleshooting

Remove to check.
Check for correct power-up
sequence.
Referenced to TP501.
Referenced to TP501.
Referenced to TP501.
Referenced to TP501.
+15VF, referenced to TP500.

-15VF, referenced to TP500.
+5VF, referenced to TP500.

4-14 Troubleshooting Model 2440 5A SourceMeter® Service Manual

Digital circuitry checks

Digital circuit problems can be checked out using Table 4-3. See “Principles of opera-

tion” for a digital circuit description.

Table 4-3

Digital circuitry checks

Step Item/component Required condition Remarks

1

Power-on test

2

U3 pin 19

3

U3 pin 7

4

U3 pin 68

5

U3, lines A0-A19

6

U3, lines D0-D15

7

U3 pin 66

8

U4 pin 7

9

U4 pin 8

10

U13 pins 34-42

11

U13 pins 26-31

12

U13 pin 24

13

U13 pin 25

14

U3 pin 43

15

U3 pin 44

16

U3 pin 45

17

U3 pin 47

RAM OK, ROM OK.

Digital common.

+5V
Low on power-up, then goes
high.
Check for stuck bits.
Check for stuck bits.

16.78MHz.
Pulse train during RS-232
I/O.
Pulse train during RS-232
I/O.
Pulse train during IEEE-488
I/O.
Pulses during IEEE-488 I/O.
Low with remote enabled.
Low during interface clear.
Pulse train.
Pulse train.
Pulse train.
Pulse train

Verify that RAM and ROM
are functional.
All signals referenced to
digital common.
Digital logic supply.
MPU RESET line.

MPU address bus.
MPU data bus.
MPU clock.
RS-232 RX line.

RS-232 TX line.

IEEE-488 data bus.

IEEE-488 command lines.
IEEE-488 REN line.
IEEE-488 IFC line.
D_ADDATA
D_DATA
D_CLK
D_STB

Model 2440 5A SourceMeter® Service Manual Troubleshooting 4-15

Analog circuitry checks

Table 4-4 summarizes analog circuitry checks.

Table 4-4

Analog circuitry checks

Step Item/component Required condition Remarks

1

TP200*

2

TP201*

3

TP202*

4

TP203*

5

TP213*

6

TP218**

7

TP219**

8

TP214**

9

TP232*

**Measured with respect to FCOM (TP500).

**Measured with respect to OCOM (TP501).

>60V voltage protection
SOURCE +10V
SOURCE +10V (SVMI)
SOURCE +10V
SOURCE +10V
OUTPUT COM
OUTPUT COM
SVMI, OUTPUT ON, 20V
Bench defaults

-13V ±1V

-5V ±0.5V

-10V ±1V

-10.5V ±1V
0V ±0.1V
7V ±0.7V
7V ±0.7V
20V ±0.5V

6.4V ±0.6V

Battery replacement

WARNING Disconnect the instrument from the power line and all other equip-

ment before changing the battery.

The volatile memories of the Model 2440 are protected by a replaceable battery when
power is off. Typical battery life is approximately 10 years, but the battery should be
replaced if the voltage drops below 2.5V regardless of age. The battery should be sus
pected if the instrument no longer retains buffer data or user-defined operating parameters
such as instrument setups, source memory, and math expressions. If the battery is absent
or totally exhausted, the display will show the “Reading buffer data lost” message shortly
after the Model 2440 is switched on.

The battery is a 3V wafer-type lithium cell, (Keithley part number BA-46), which is
located on the digital board. Replacement of the battery requires removal of the case cover
and analog board assembly. (See

NOTE Calibration constants and user defined parameters will be lost when the battery

is replaced. The Model 2440 must be re-calibrated (Section 2) after the battery
is replaced.

-

Troubleshooting

Section 5.)

4-16 Troubleshooting Model 2440 5A SourceMeter® Service Manual

Battery replacement precautions

WARNING The precautions below must be followed to avoid personal injury.

1. Wear safety glasses or goggles when working with lithium batteries.

2. Do not short the battery terminals together.

3. Keep lithium batteries away from all liquids.

4. Do not attempt to recharge lithium batteries.

5. Observe proper polarity when installing the battery.

6. Do not incinerate or otherwise expose the battery to excessive heat (>60°C).

7. Bulk quantities of lithium batteries should be disposed of as hazardous waste.

Battery replacement procedure

1. Remove the case cover and analog board assembly as covered in Section 5.

2. Locate the battery on the digital board.

3. Carefully unsolder and remove the old battery.

4. Install and solder the new battery in place.

5. Reassemble the instrument, and turn it on. The “Reading buffer data lost” error
message will be displayed.

6. Send the :SYST:MEM:INIT command via remote to perform the following:

• Clear the reading buffer.

• Initialize instrument setups 1 through 4 to present instrument settings.

• Initialize all 100 source memory locations to present instrument settings.

• Delete user math expressions.

Model 2440 5A SourceMeter® Service Manual Troubleshooting 4-17

No comm link error

A “No Comm Link” error indicates that the front panel processor has stopped communi­cating with the main processor, which is located on the digital board. This error indicates
that one of the main processor ROMs may require re-seating in its socket. ROMs may be
reseated as follows:

1. Turn off the power, and disconnect the line cord and all other test leads and cables
from the instrument.

2. Remove the case cover as outlined in Section 5.

3. Remove the analog board assembly as outlined in Section 5.

4. Locate the two firmware ROMS, U15 and U16, located on the digital board. These
are the only ICs installed in sockets. (Refer to the component layout drawing at the
end of

Section 6 for exact locations.)

5. Carefully push down on each ROM IC to make sure it is properly seated in its
socket.

CAUTION Be careful not to push down excessively, or you might crack the digital

board.

6. Connect the line cord, and turn on the power. If the problem persists, additional
troubleshooting will be required.

Troubleshooting

4-18 Troubleshooting Model 2440 5A SourceMeter® Service Manual

5

Disassembly

Disassembly

5-2 Disassembly Model 2440 5A SourceMeter® Service Manual

Introduction

This section explains how to handle, clean, and disassemble the Model 2440. Disassembly
drawings are located at the end of this section.

Handling and cleaning

To avoid contaminating PC board traces with body oil or other foreign matter, avoid
touching the PC board traces while you are repairing the instrument. Motherboard areas
covered by the shield have high-impedance devices or sensitive circuitry where contami
nation could cause degraded performance.

Handling PC boards

Observe the following precautions when handling PC boards:

• Wear cotton gloves.

• Only handle PC boards by the edges and shields.

• Do not touch any board traces or components not associated with repair.

• Do not touch areas adjacent to electrical contacts.

• Use dry nitrogen gas to clean dust off PC boards.

-

Solder repairs

Observe the following precautions when you must solder a circuit board:

• Use an OA-based (organic activated) flux, and take care not to spread the flux to
other areas of the circuit board.

• Remove the flux from the work area when you have finished the repair by using
pure water with clean, foam-tipped swabs or a clean, soft brush.

• Once you have removed the flux, swab only the repair area with methanol, then
blow-dry the board with dry nitrogen gas.

• After cleaning, allow the board to dry in a 50°C, low-humidity environment for
several hours.

Model 2440 5A SourceMeter® Service Manual Disassembly 5-3

Static sensitive devices

CMOS devices operate at very high impedance levels. Therefore, any static that builds up
on you or your clothing may be sufficient to destroy these devices if they are not handled
properly. Use the following precautions to avoid damaging them:

CAUTION Many CMOS devices are installed in the Model 2440. Handle all semi-

conductor devices as being static sensitive.

• Transport and handle ICs only in containers specially designed to
prevent static build-up. Typically, you will receive these parts in
anti-static containers made of plastic or foam. Keep these devices
in their original containers until ready for installation.

• Remove the devices from their protective containers only at a
properly grounded work station. Also, ground yourself with a
suitable wrist strap.

• Handle the devices only by the body; do not touch the pins.

• Ground any printed circuit board into which a semiconductor

device is to be inserted to the bench or table.

• Use only anti-static type desoldering tools.

• Use only grounded-tip solder irons.

• Once the device is installed in the PC board, it is normally ade-

quately protected, and you can handle the boards normally.

Disassembly

Assembly drawings

Use the assembly drawings located at the end of this section to assist you as you disassem­ble and re-assemble the Model 2440. Also, refer to these drawings for information about
the Keithley part numbers of most mechanical parts in the unit. Assembly drawings
include:

• Front panel assembly — 2440-040

• Analog board/heat sink/shield assembly — 2440-050

• Chassis assembly — 2440-051

• Chassis/analog board assembly — 2440-052

• Final chassis assembly — 2440-053

5-4 Disassembly Model 2440 5A SourceMeter® Service Manual

Case cover removal

Follow the steps below to remove the case cover to gain access to internal parts.

WARNING Before removing the case cover, disconnect the line cord and any test

leads from the instrument.

1. Remove handle — The handle serves as an adjustable tilt-bail. Adjust its position

by gently pulling it away from the sides of the instrument case and swinging it up
or down. To remove the handle, swing the handle below the bottom surface of the
case and back until the orientation arrows on the handles line up with the orienta
tion arrows on the mounting ears. With the arrows lined up, pull the ends of the
handle away from the case.

2. Remove mounting ears — Remove the screw that secures each mounting ear. Pull

down and out on each mounting ear.

NOTE When reinstalling the mounting ears, make sure to mount the right ear to the

right side of the chassis, and the left ear to the left side of the chassis. Each ear
is marked “RIGHT” or “LEFT” on its inside surface.

-

3. Remove rear bezel — To remove the rear bezel, loosen the two screws that secure

the rear bezel to the chassis, then pull the bezel away from the case.

4. Remove grounding screws — Remove the two grounding screws that secure the

case to the chassis. They are located on the bottom of the case at the back.

5. Remove chassis — To remove the case, grasp the front bezel of the instrument,

and carefully slide the chassis forward. Slide the chassis out of the metal case.

NOTE To gain access to the components under the analog board shield, remove the

shield, which is secured to the analog board by a single screw.

Model 2440 5A SourceMeter® Service Manual Disassembly 5-5

Analog board removal

Perform the following steps to remove the analog board. This procedure assumes that the
case cover is already removed.

1. Disconnect the front and rear input terminals.
You must disconnect these input terminal connections for both the front and rear
inputs:

• INPUT/OUTPUT HI and LO

• 4-WIRE SENSE HI and LO

•V, Ω, GUARD and GUARD SENSE (rear panel only)
Remove all the connections by pulling the wires off the pin connectors, then
remove the ferrite noise filters from the chassis. During re-assembly, use the fol
lowing table to identify input terminals:

Input terminals Front wire color Rear wire color

INPUT/OUTPUT HI
INPUT/OUTPUT LO
4-WIRE SENSE HI
4-WIRE SENSE LO
V, Ω, GUARD
GUARD SENSE

2. Unplug cables.

• Carefully unplug the ribbon cables at J1027, J1028, and J1029.

• Unplug the ON/OFF cable at J1034.

3. Remove screws.

• Remove the two fastening screws that secure the analog board assembly to the

chassis. These screws are located on the side of the board opposite from the
heat sink.

• Remove the two screws that secure the heat sink to the chassis.

4. Remove analog board assembly.
After all screws have been removed, carefully lift the analog board assembly free
of the main chassis.

5. Disassemble analog board assembly.

• Remove the screws that secure the analog board and heat sink to the analog
board subchassis.

• Carefully remove the heat sink by sliding the clips off the power transistors.

Red

Black

Yellow

Gray

-

-

White/Red
White/Black
White/Yellow
White/Gray
White
Blue/White

-

Disassembly

CAUTION Be careful not to damage the heat sink insulation layer.

• Remove the analog board from the subchassis.

• Remove the four screws that secure the bottom cover, then remove the cover
from the bottom of the PC board.

NOTE When reinstalling the heat sink, make sure that all clips are properly installed

and centered on each pair of output transistors.

5-6 Disassembly Model 2440 5A SourceMeter® Service Manual

Digital board removal

Perform the following steps to remove the digital board. This procedure assumes that the
analog board assembly is already removed.

NOTE In order to remove the digital board, the display board must first be removed.

1. Remove the IEEE-488, Digital I/O, and RS-232 fasteners.
The IEEE-488, Digital I/O, and RS-232 connectors each have two nuts that secure
the connectors to the rear panel. Remove these nuts.

2. Remove the POWER switch rod.
At the switch, place the edge of a flat-blade screw driver in the notch on the push­rod. Gently twist the screw driver while pulling the rod from the shaft.

3. Unplug cables:

• Unplug the display board ribbon cable.

• Unplug the cables going to the power supply.

• Unplug the rear panel power module cable.

• The fan may need to be removed.

4. Remove digital board.
Slide the digital board forward until it is free of the guide pins, then remove the
board.
During reassembly, replace the board, and start the IEEE-488, Digital I/O, and RS­232 connector nuts and the mounting screw. Tighten all the fasteners once they are
all in place and the board is correctly aligned.

Front panel disassembly

Use the following procedures to remove the display board and/or the pushbutton switch
pad.

1. Unplug the display board ribbon cables.

2. Remove the front panel assembly.
This assembly has four retaining clips that snap onto the chassis over four pem nut
studs. Two retaining clips are located on each side of the front panel. Pull the
retaining clips outward and, at the same time, pull the front panel assembly for
ward until it separates from the chassis.

3. Using a thin-bladed screw driver, pry the plastic PC board stop (located at the bot­tom of the display board) until the bar separates from the casing. Pull the display
board from the front panel.

4. Remove the switch pad by pulling it from the front panel.

-

Model 2440 5A SourceMeter® Service Manual Disassembly 5-7

Removing power components

The following procedures to remove the power supply and/or power module require that
the case cover and motherboard be removed, as previously explained.

Power module removal

Perform the following steps to remove the rear panel power module:

1. Remove the analog board.

2. Unplug the cable connecting the power module to the digital board.

3. Disconnect the power module's ground wire. This green and yellow wire connects
to a threaded stud on the chassis with a kep nut.

4. Squeeze the latches on either side of the power module while pushing the module
from the access hole.

WARNING To avoid electrical shock, which could result in injury or death, the

ground wire of the power module must be connected to chassis
ground. When installing the power module, be sure to reconnect the
green and yellow ground wire to the threaded stud on the chassis.

Instrument reassembly

Reassemble the instrument by reversing the previous disassembly procedures. Make sure
that all parts are properly seated and secured, and that all connections are properly made.
To ensure proper operation, replace the analog signal wire ferrite noise filters, and
securely fasten the shield.

Disassembly

WARNING To ensure continued protection against electrical shock, verify that

power line ground (green and yellow wire attached to the power mod
ule) is connected to the chassis.

Also make sure the two bottom case screws are properly installed to
secure and ground the case cover to the chassis.

-

5-8 Disassembly Model 2440 5A SourceMeter® Service Manual

6

Replaceable Parts

Replaceable Parts

6-2 Replaceable Parts Model 2440 5A SourceMeter® Service Manual

Introduction

This section contains replacement parts information and component layout drawings for
the Model 2440.

Parts lists

The electrical parts lists for the Model 2440 are shown tables at the end of this section. For
part numbers to the various mechanical parts and assemblies, use the Miscellaneous parts
list and the assembly drawings provided at the end of

Section 5.

Ordering information

To place an order, or to obtain information concerning replacement parts, contact your
Keithley representative or the factory (see inside front cover for addresses). When order
ing parts, be sure to include the following information:

• Instrument model number (Model 2440)

• Instrument serial number

• Part description

• Component designation (if applicable)

• Keithley part number

-

Factory service

If the instrument is to be returned to Keithley Instruments for repair, perform the
following:

• Call the Repair Department at 1-800-552-1115 for a Return Material Authorization
(RMA) number.

• Complete the service form at the back of this manual, and include it with the instru­ment.

• Carefully pack the instrument in the original packing carton.

• Write ATTENTION REPAIR DEPARTMENT and the RMA number on the ship­ping label.

Model 2440 5A SourceMeter® Service Manual Replaceable Parts 6-3

Component layouts

The component layouts for the various circuit boards are provided on the following pages.
Drawings include:

• Analog board — 2440-120

• Display board — 2400-110

• Digital board — 2440-140

Table 6-1

Analog board parts list

Keithley

Circuit Designation Description

C200-C203, C205-C210, C225,

C226, C231, C232
C204,C411, C608, C609 CAP, .01UF, 10%, 50V, CERAMIC C-491-.01
C211, C212, C213, C214, C301,

C302
C215-C222, C611, C331, C332,

C333, C334
C223, C224, C227, C229, C234-

C236, C239, C240
C230, C233 CAP, 7.5P, 10%, 100V, CERAMIC C-452-7.5P
C237, C238, C242, C243, C248,

C249, C254, C255
C241 CAP, 1000PF, 1%, 50V, CERAMIC C-347-1000P
C246, C336 CAP, 3300PF, 10%, 100V, CERAMIC C-430-3300P
C247 CAP, .01, 5%, 50V, NPO C-514-.01
C250, C251, C272, C297, C298,

C299, C300, C524
C258, C259, C260-C263, C269-

C271, C273-C282
C267, C268 CAP, 1000P, 10%, 100V, CERAMIC C-451-1000P
C283 CAP, 100P, 10%, 100V, CERAMIC C-451-100P
C284-C291, C305-C310, C321,

C322, C548, C558
C296, C330, C400 CAP, 270PF, 2.5%, 630V, POLYPROPYLENE C-405-270P
C311 CAP, 100UF, 20%, 16V, TANTALUM C-504-100
C312-C319 CAP, 10PF, 5%, 100V, CERAMIC C-372-10P
C320 CAP, 33PF, 5%, 100V, CERAMIC C-465-33P
C323, C324, C325, C326, C603,

C604, C615
C327 CAP, 390P, 10%, 100V, CERAMIC C-451-390P

CAP, .1UF, 10%, 25V, CERAMIC C-495-.1

CAP, 1000PF, 10%, 50V, MONO CERAMIC C-452-1000P

CAP, 100PF, 5%, 100V, CERAMIC C-465-100P

CAP, 33PF, 5%, 100V, CERAMIC C-465-33P

CAP, .1UF, 10%, 25V, CERAMIC C-495-.1

CAP, .1UF, 10%, 25V, CERAMIC C-495-.1

CAP, .1UF, 10%, 25V, CERAMIC C-495-.1

CAP, .1UF, 10%, 25V, CERAMIC C-495-.1

CAP, 47P, 5%, 100V, CERAMIC C-465-47P

Part

No.

Replaceable Parts

6-4 Replaceable Parts Model 2440 5A SourceMeter® Service Manual

Table 6-1 (continued)

Analog board parts list

Keithley

Circuit Designation Description

Part No.

C328 CAP, 22P, 2%, 200V, CERAMIC C-531-22P
C329 CAP, 220PF, 10%, 100V, CERAMIC C-451-220P
C409, C410 CAP, .15UF, 20%, 50V, CERAMIC C-418-.15
C412 CAP, 1UF, 20%, 35V, TANTALUM C-494-1
C501, C503 CAP, 3.3, 20%, 250V, ALUM ELECTROLYTIC C-400-3.3
C502, C504, C505, C506, C550,

CAP, .01U, 10%, 500V, CERAMIC C-497-.01

C551, C552, C553
C512, C514, C256, C257 CAP, 22PF, 10%, 100V, CERAMIC C-451-22P
C513 CAP, 560PF, 2.5%, 630V, POLYPROPYLENE C-405-560P
C515, C541 CAP, .1UF, 20%, 50V, CERAMIC C-418-.1
C522, C523, C526, C527 CAP, 3300P, 10%, 500V, CERAMIC C-497-3300P
C525, C542, C549, C561, C564,

CAP, .1UF, 10%, 25V, CERAMIC C-495-.1

C585
C528, C533, C567, C568, C569,

CAP, 3300P, 10%, 500V, CERAMIC C-497-3300P

C570, C663, C664
C534, C535 CAP, 47U, 20%, 50V, ALUM C-579-47
C543 CAP, 10PF, 10%, 1000V, CERAMIC C-64-10P
C544, C545, C546, C547 CAP, .01U, 10%, 500V, CERAMIC C-497-.01
C556, C557, C559, C560, C562,

CAP, 22UF, 20%, 25V, TANTALUM C-440-22

C563, C616
C565, C566, C581, C582, C600,

CAP, .1UF, 10%, 25V, CERAMIC C-495-.1

C601, C602, C605
C583, C584 CAP, 1000PF, 20%, 50V, CERAMIC C-418-1000P
C606, C607, C613, C614, C617,

CAP, .1UF, 10%, 25V, CERAMIC C-495-.1

C618, C619, C620
C610, C612 CAP, 2200P, 10%, 100V, CERAMIC C-430-2200P
C621, C622, C623, C624, C625,

CAP, .1UF, 10%, 25V, CERAMIC C-495-.1

C650, C651, C652
C659-C662 CAP, .1UF, 10%, 25V, CERAMIC C-495-.1
CR200-CR205, CR207, CR208,

DIODE, SWITCHING, MMBD914 RF-83

CR210-CR213
CR206, CR209, CR222, CR223,

DIODE, 1N3595 RF-43

CR230-CR233
CR216-CR221, CR235, CR236,

DIODE, SWITCHING, MMBD914 RF-83

CR239, CR518
CR224, CR225 SCHOTTKY BARRIER RECTIFIER RF-154
CR237, CR523 DIODE, DUAL SWITCHING, BAV99L RF-82
CR400, CR401 DIODE, 1N3595 RF-43
CR517, 519 SWITH MODE POWER RECTIFIER RF-155

Model 2440 5A SourceMeter® Service Manual Replaceable Parts 6-5

Table 6-1 (continued)

Analog board parts list

Keithley

Circuit Designation Description

CR522, CR524, CR525 DIODE, SWITCHING, MMBD914 RF-83
CR600 DIODE, DUAL HSM-2822T31 RF-95
CR601 DIODE, SCHOTTKY, SD103C RF-113
CR602 SCHOTTKY DIODE RF-125
HS1, HS2, HS3, HS4, HS5, HS6,

HS7, HS17, HS19
J1027, J1036 CONN, HEADER STRAIGHT SOLDER PIN CS-368-16
J1028 CONNECTOR, HEADER STRAIGHT SOLDER

J1029 CONN, MALE, 5-PIN (MOLEX 42491) CS-784-5
J1034, J1037, J1038 LATCHING HEADER, FRICTON, SGL ROW CS-724-3
K200-K205 N.C RELAY, 1 FORMB, AQV214S RL-176
K206, K207, K208 FORM 2A2B POLARIZED RELAY, S28B-5V RL-207
K211, K500 RELAY, SURFACE MOUNT RL-188
K215 NON LATCHING RELAY RL-242
L201, L500, L501 CHOKE, SHIELD BEAD CH-52
L600, L601, L602 FERRITE CHIP, 600 OHM, BLM32A07 CH-62
L603 FERRITE CHIP, 600 OHM, BLM32A07 CH-62
Q200, Q201, Q202, Q203, Q204,

Q205, Q206, Q207
Q208, Q210, Q212, Q214, Q216,

Q218
Q209, Q211, Q213, Q215, Q217,

Q219
Q220 TRANS, NPN SILICON, MJE340 TG-209
Q221 TRANS, PNP POWER, MJE350 TG-210
Q222, Q224 TRANS, N-CHAN JFET, SST4393 TG-263
Q223, Q229, Q234-Q239, Q244,

Q245, Q246, Q255
Q225 TRANS, NPN SILICON, MJD340 TG-373
Q226 TRANS, PNP SILICON, MJD350 TG-374
Q227, Q257, Q501, Q510, Q515,

Q517, Q519, Q522
Q228, Q247, Q248, Q520, Q601 TRANS, PNP, MMBT3906L TG-244
Q240, Q241 TRANS, N CHANNEL JFET, SNJ132199 TG-294
Q242, Q243 TRANS, N-CHAN MOSFET, TN254ON8 TG-274
Q249, Q528 TRANS, NPN SILICON, BC846BL, TG-278
Q250, Q529 TRANS, PNP, BC856BL TG-287

HEAT SINK HS-55

PIN

TRANS, N CHANNEL JFET, SNJ132199 TG-294

TRANS, NPN CATV SILICON, MPSH17 TG-221

TRANS, CURR REG, CDLL5313 TG-321

TRANS, N-MOSFET, VN0605T TG-243

TRANS, NPN, MMBT3904 TG-238

Part No.

CS-368-14

Replaceable Parts

6-6 Replaceable Parts Model 2440 5A SourceMeter® Service Manual

Table 6-1 (continued)

Analog board parts list

Keithley

Circuit Designation Description

Part No.

Q256, Q258, Q401, Q404, Q405,

TRANS, N-MOSFET, VN0605T TG-243

Q410, Q411, Q420
Q402, Q409, Q259 TRANS, N-CHAN DMOS, FET TN2504N8 TG-261
Q403, Q406, Q407, Q408 TRANS, N-CHAN JFET, SST109 TG-266
Q412, Q414 TRANS, N-MEGAFET, RFD14N05LSM TG-267
Q415, Q416 TRANS, HEXFET POWER MOSFET, IRFR5305 TG-377
Q417, Q419 TRANS, N-CHANNEL MOSFET,

TG-339

RFD16N05LSM
Q418, Q542, Q230 TRANS, P-CHAN, MOSFET, TP0610T TG-259
Q500, Q503 TRANS, POWER MOSFET, IRF3415S TG-372
Q502, Q540, Q541, Q602-Q605 TRANS, N-MOSFET, VN0605T TG-243
Q504, Q514, Q516, Q518 N-CHANNEL POWER MOSFET TG-349
Q507, Q521, Q523, Q525 P-CHANNEL POWER MOSFET TG-348
Q524, Q534, Q535, Q537, Q538,

TRANS, NPN, MMBT3904 TG-238

Q600
Q526, Q527, Q530, Q531 TRANS, N-CHANNEL, MOSFET, SI9410DY TG-302
Q532, Q536 TRANS, N-CHANNEL, FET, IRF630 TG-214
Q533, Q539 TRANS, P-CHANNEL, 200V FET, IRF9630 TG-215
R117-R128, R133-R136, R141-

RES, 10K, 5%, 250MW, METAL FILM R-376-10K

R144
R129, R155, R211, R224-R229,

RES, 10K, 1%, 100MW, THICK FILM R-418-10K

R234-R237
R130 RES, 10K, 1%, 100MW, THICK FILM R-418-10K
R137-140, R145-149, R713, R714 RES, 10K, 5%, 250MW, METAL FILM R-376-10K
R150, R151, R389, R390, R451,

RES, 1K, 1%, 100MW, THICK FILM R-418-1K

R520, R531, R559
R152, R656 RES, 4.99K, .1%, .125W, THIN FILM R-456-4.99K
R153, R154, R240, R243, R248,

RES, 4.99K, 1%, 100MW, THICK FILM R-418-4.99K

R251, R253, R254
R200, R201, R203, R232, R238 RESISTOR NETWORK, 10K-10K TF-236
R202, R204, R252, R255, R256,

RES, 100K, 1%, 100MW, THICK FILM R-418-100K

R259, R260, R263
R205, R310, R485, R552, R595,

RES, .0499, 1%, 100MW, THICK FILM R-418-.0499

R598, R723, R724
R207 RES, 20K, .1%, .125W, THIN FILM R-456-20K
R208, R210 RES, 768, 1%, 100MW, THICK FILM R-418-768
R209, R268, R269, R270, R271,

RES, 1M, 1%, 100MW, THICK FILM R-418-1M

R672
R213 RES NET, 5K, .1%, 668A TF-243-5K

Model 2440 5A SourceMeter® Service Manual Replaceable Parts 6-7

Table 6-1 (continued)

Analog board parts list

Keithley

Circuit Designation Description

Part No.

R216, R221, R223, R274, R275,

R276, R277, R278
R217 RES, 121K, 1%,100MW, THICK FILM R-418-121K
R218 RES, 80.6K, 1%, 100MW, THICK FILM R-418-80.6K
R219, R220, R222, R230, R231,

R373, R374, R616
R241, R242, R249, R250, R653,

R664
R244-R247, R281, R282, R284-

R286, R288, R301
R257, R258, R261, R262, R265,

R266, R311, R312
R264, R267, R364, R370, R371,

R372, R402
R272, R273, R347, R348, R511,

R512, R589
R279 RES, 20K, 1%, 100MW, THICK FILM R-418-20K
R280, R516, R523 RES, 4.02K, 1%, 100MW, THICK FILM R-418-4.02K
R283, R287, R297, R299, R349,

R350, R351, R352
R289, R303, R681, R684 RES, 20K, .1%, .125W, THIN FILM R-456-20K
R290, R309, R336, R340, R343,

R344, R353, R355
R291, R293, R682, R685 RES, 42.7K, .1%, .125W, THIN FILM R-456-42.7K
R292, R338, R527, R528, R533,

R535, R544, R546
R294, R295, R296 RES, 100K, .1%, .125W, THIN FILM R-456-100K
R298, R300 RES, 150K, 1%, 100MW, THICK FILM R-418-150K
R302 RES, .0499, 1%, 100MW, THICK FILM R-418-.0499
R304, R305, R306, R548 RES, 33, 5%, 250MW, METAL FILM R-376-33
R307, R413, R652, R665 RES, 357, 1%, 100MW, THICK FILM R-418-357
R308, R379-R387, R391, R392 RES, 475, 1%, 100MW, THICK FILM R-418-475
R313, R314, R315, R316, R317,

R334, R335, R337
R318, R563, R358 RES, 15K, 1%, 100MW, THICK FILM R-418-15K
R332, R423, R430, R604, R606,

R436
R339, R357, R366, R367, R424,

R425, R426, R429

RES, 20K, 1%, 100MW, THICK FILM R-418-20K

RES, 49.9K, 1%, 100MW, THICK FILM R-418-49.9K

RES, 140K, 1%, 100MW, THICK FILM R-418-140K

RES, 10K, 1%, 100MW, THICK FILM R-418-10K

RES, 4.99K, 1%, 100MW, THICK FILM R-418-4.99K

RES, 100K, 1%, 100MW, THICK FILM R-418-100K

RES, 249K, 1%, 100MW, THICK FILM R-418-249K

RES, 30.1K, 1%, 100MW, THICK FILM R-418-30.1K

RES, 1K, 1%, 100MW, THICK FILM R-418-1K

RES, 100K, 1%, 100MW, THICK FILM R-418-100K

RES, 4.99K, 1%, 100MW, THICK FILM R-418-4.99K

RES, 499, 1%, 100MW, THICK FILM R-418-499

RES, 4.99K, 1%, 100MW, THICK FILM R-418-4.99K

Replaceable Parts

6-8 Replaceable Parts Model 2440 5A SourceMeter® Service Manual

Table 6-1 (continued)

Analog board parts list

Keithley

Circuit Designation Description

Part No.

R341, R342, R505 RES, 13K, 1%, 100MW, THICK FILM R-418-13K
R345 RES, 316K, 1%, 100MW, THICK FILM R-418-316K
R346 RES, 392K, 1%, 100MW, THICK FILM R-418-392K
R354, R437 RES, 560K, 5%, 250MW, METAL FILM R-376-560K
R356, R359, R361, R362, R365,

RES, 1K, 1%, 100MW, THICK FILM R-418-1K

R369, R418, R419
R363 RES NET, VARIOUS, .1%, .1W TF-283
R368, R212 RES, 332, 1%, 100MW, THICK FILM R-418-332
R375, R376, R576, R578, R536,

RES, 10, 10%, 100MW, THICK FILM R-418-10

R537
R388, R393-R399, R411, R412,

RES, 357, 1%, 100MW, THICK FILM R-418-357

R699
R403, R404, R416, R417, R459,

RES, 100K, 1%, 100MW, THICK FILM R-418-100K

R488, R560
R420, R421, R456, R458, R460,

RES, 1K, 1%, 100MW, THICK FILM R-418-1K

R462, R466, R472
R422 RES, 4.7K, 5%, 250MW, METAL FILM R-376-4.7K
R431, 432 RES, 3.01K, 1%, 100MW, THICK FILM R-418-3.01K
R433, R434 RES, 1K, 1%, 100MW, THICK FILM R-418-1K
R435, R504, R590, R673, R688,

RES, 10K, 1%, 100MW, THICK FILM R-418-10K

R689, R716, R715,
R438, R439, R592, R617, R622,

RES, 10K, 1%, 100MW, THICK FILM R-418-10K

R654, R655, R687
R450 RES, 200K, .1%, 1/10W, METAL FILM R-263-200K
R452 RES, 21.93K, .1%, 1/10W, METAL FILM R-263-21.93K
R453 RES, 1.82K, .1%, 1/10W, METAL FILM R-263-1.82K
R454, R455, R467, R468, R469,

RES, 100, .1%, 1/10W, METAL FILM R-263-100

R470, R471
R457, R461, R463, R473, R479,

RES, 30.1K, 1%, 100MW, THICK FILM R-418-30.1K

R697, R698
R475 RES, 1, 1%, 1/5W, WIRE R-501-1
R478, R481, R489, R502, R510,

RES, 1K, 1%, 100MW, THICK FILM R-418-1K

R558, R675, R704
R482, R484, R487 RES, 6.04K, 1%, 100MW, THICK FILM R-418-6.04K
R483, R691, R695, R721 RES, 2K, 1%, 100MW, THICK FILM R-418-2K
R490 RES, 205, .1%, 1/10W, METAL FILM R-263-205
R503, R545, R587 RES, 15K, 1%, 100MW, THICK FILM R-418-15K
R508, R509, R506, R507 RES, 150K, 5%, 250MW, METAL FILM R-376-150K

Model 2440 5A SourceMeter® Service Manual Replaceable Parts 6-9

Table 6-1 (continued)

Analog board parts list

Keithley

Circuit Designation Description

Part No.

R517, R524, R564, R565, R566,

R567
R521, R658 RES, 2M, 1%, 100MW, THICK FILM R-418-2M
R525, R526 RES, 1.21K, 1%, 100MW, THICK FILM R-418-1.21K
R530, R532, R534, R712 RES, 1K, 1%, 100MW, THICK FILM R-418-1K
R538, R540, R568, R569 RES, .5, 5%, 1W, METAL FILM R-444-.5
R539, R541, R542, R543 RES, .25, 1%, IN, METAL R-444-.25
R547, R588 RES, 100K, 1%, 100MW, THICK FILM R-418-100K
R553, R554 RES, 75K, 1%, 100MW, THICK FILM R-418-75K
R561, R562, R600, R500, R515,

R722
R570, R571, R573, R581, R705 RES, 249, 1%, 100MW, THICK FILM R-418-249
R572, R574, R580, R582 RES, 200K, 1%, 100MW, THICK FILM R-418-200K
R575, R579, R614, R615 RES, 2.21K, 1%, 100MW, THICK FILM R-418-2.21K
R586 RES, 10, 5%, 125MW, METAL FILM R-375-10
R601, R603, R605, R608, R626,

R702, R703
R602, R607 RES, 150, 5%, 250MW, METAL FILM R-376-150
R609 RES NET TF-245
R610 RES, 1.28M, .1%, 1/8W, METAL FILM R-176-1.28M
R611, R621 RES, 475, 1%, 100MW, THICK FILM R-418-475
R612 RES, 5.11K, 1%, 100MW, THICK FILM R-418-5.11K
R613, R624, R659, R660 RES, 100, 1%, 100MW, THICK FILM R-418-100
R618 RES, 34K, 1%, 100MW, THICK FILM R-418-34K
R619 RES, 4.75K, 1%, 100MW, THICK FILM R-418-4.75K
R620 RES, 82.5, 1%, 100MW, THICK FILM R-418-82.5
R623 RES, 10, 10%, 100MW, THICK FILM R-418-10
R650 RES NET, 9K-1K, MICRO DIVIDER TF-246-2
R651 RES NET, 20K, .1%, .2W, MICRO DIVIDE TF-250
R657, R692, R696 RES, 1M, 1%, 100MW, THICK FILM R-418-1M
R666 RES NET, 3K, 12K, 0.1%, 100MW, THIN FILM TF-237-2
R670 RES, 1K, 1%, 100MW, THIN FILM R-438-1K
R671 RES, .0499, 1%, 100MW, THICK FILM R-418-.0499
R680 RES, 8.87K, 1%, .1W, THIN FILM R-438-8.87K
R683, R686 RES, 1K, .1%, .125W, THIN FILM R-456-1K
R690, R694 RES, 100K, 5%, 250MW, METAL FILM R-376-100K
R700, R701 RES, 49.9K, 1%, 100MW, THICK FILM R-418-49.9K
R706, R707, R708, R709, R501,

R514, R529,

RES, 12.1, 1%, 1/4W, METAL FILM R-391-12.1

RES, 100K, 1%, 100MW, THICK FILM R-418-100K

RES, 4.99K, 1%, 100MW, THICK FILM R-418-4.99K

RES, 1K, 1%, 100MW, THICK FILM R-418-1K

Replaceable Parts