Tektronix 7153 Instruction Manual

Model 7153 High Voltage Low

Current Matrix Card

Instruction Manual

Contains Operating and Servicing Information

Model

7153

High Voltage Low

Instruction Manual

0 1990, Keithley Instruments, Inc.

Test Instrumentation Croup

All rights reserved.

Cleveland, Ohio, U.S.A.

November 1990, First Printing

Document Number: 7153.YOLRev. A

SAFETY PRECAUTIONS

The following safety precautions should be observed before using the
Model 7153 and the associated instruments.

This matrix card is intended for use by qualified personnel who recognize
shock hazards and are familiar with the safety precautions required to
avoid possible injury. Read over this manual carefully before using the
card.

ALWAYS remove power from the entire system (mainframe, test instru­ments, DUT, etc.) and discharge any capacitors before doing any of the
following:

1. Installing or removing the matrix card from the mainframe.

2. Connecting or disconnecting cables from the matrix card.

Exercise extreme caution when a shock hazard is present at the test fixture.
User-supplied lethal voltages may be present on the fixture or the connec­tor jack. The American National Standards Institute (ANSI) states that a
shock hazard exists when voltage levels greater than 30V RMS or 42.4V
peak are present. A good safety practice is to expect that hazardous volt­age is present in any unknown circuit before measuring.

Do not exceed 1300V between any two pins or between any pin and chas­sis ground.

Inspect the connecting cables and test leads for possible wear, cracks, or
breaks before each use.

For maximum safety, do not touch the test fixture, test cables or any instru­ments while power is applied to the circuit under test.

Do not touch any object which could provide a current path to the com­mon side of the circuit under test or power line (earth) ground.

Do not exceed the maximum signal levels of the test fixture, as defined in

the specifications and operation section of this manual.

Do not connect the matrix card (or any other instrumentation) to humans.

Do not connect the matrix card directly to unlimited power circuits. This
product is intended to be used with impedance limited sources. NEVER
connect the tmatrix card directly to AC mains.

When connecting sources, install protective devices to limit fault current
and voltage to the card.

The chassis connections must only be used as shield connections for
measuring circuits; NOT as safety earth ground connections.

The outer shields (including the triax connector shells) of the Model
7153-TRX are not connected to safety earth ground. NEVER apply more
than 30V to these shields.

To prevent voltages from being exposed or connections from shorting to­gether, make sure cables are properly connected before applying voltage.

Do not apply power to cables that are not connected.

Model

MATRIX CONFIGIJRATION: 4 TOWS by 5 columns.
CROSSPOINT CONFIGURATION (Signal and Guard): Z-pole Form A.
CONNECTORTYPE: Miniature coax, M-Series Receptacle.
RELAY DRWE CURRENT: 40mA (per crosspoint).
MAx,MuM SlGNAL LEVEL:

IA carry / 0.5A switched.
IOVA peak (resistive load).
Maximum Between Any 2 Pins or Chassis: 13OOV.

Max,mum Between Signal and Guard: 200”.

CONTACT LIPB:

Cold Switching: 108closures.

Maximum Signal Level: lo5 closures.
PATH RESISTANCE: <IO per contact to rated life.
ACTUATION TIME: <2ms evctusivc of mainframe.
ISOLATION:

Path to Path: >lOW and <IpF.

Differential (Signal to Guard): >lO”Q and 4OOpF.

Gammon Mode 6tgnat and Guard to Chassis): >lOQ and 4OOpP.
CROSSTALK (Adjacent Path to Path): <-50dB at IMHz, 50 n load.

INSERTION LOSS (1 MHz, 5On Source, 5On Load): 0.1 dB typical.
3dB BANDWIDTH (500 Load): 60 MHz typical.
OPPSET CURRENT (Signal to Guard): 4pA (1OfA typical)
CONTACT POTENTIAL (Signal to Guard): <5OpV typical.
ENVIRONMENT:

Isolation and Offset Current Specifications: WC, 40% R.H.
~,~~wAI;~~~~“,;~~$$ up to 35°C at 70% R.H.

7153

Specifications

c

VIMENSIONS, WEIGHT: 30mm high x 114mm wide x 288mm long

x 11.34 in.,. Net weight 0.60 kg (20.0 oz.).

)RY

ACCESSC

surrLif3.D:

Insttiction manual

(1.18 in. x

SECTION 1

General Information

Contains information on Model 7153 features, specifications,
and accessories.

SECTION 2
Operation

Details installation of the Model 7153 High Voltage Low Cur­rent Matrix Card within theModel 705 and 706 scanners. covers
card connections, and also discusses matrix mainfrake pro­gramming and measurement considerations.

SECTION 3
Applications

Gives three typical applications for the Model 7153, including
semiconductor switching matrix, van der Pauw resistivity mear­urements, and semiconductor parameter analysis using the HP

41150.

SECTION 4
Service information

Contains Matrix card cleaning and performance verification
procedures for the matrix card.

SECTION 5

Replaceable Parts

Lists replacement pans, and also includes component layout
and schematic drawing for the Model 7153

Table of Contents

SECTION 1 - General Information

1.1

1.2

1.3 WARRANTY INFORMATION

1.4

1.5

1.6

1.7

1.7.1

1.7.2

1.7.3

1.8

1.9

INTRODUCTION ..................

FEATURES,

MANUAL ADDENDA

SAFETY SYMBOLS AND TERMS .......

SPECIFICATIONS ..................

UNPACKING AND INSPECTION ......

Inspection for Damage
Shipment Contents

Additional Instruction Manual .......

REPACKING FOR SHIPMENT .........

OPTIONAL CABLE ASSEMBLY

.......................

.........

...............

............

...............

........

SECTION 2 - Operation

2.1

2.2

2.3

2.4

2.5 CARD INSTALLATION AND REMOVAL

2.5.1

2.5.2

2.6

2.6.1

2.6.2 Recommended Cables and Adapters

2.6.3

2.6.4

2.6.5

2.7

2.8

2.8.1

INTRODUCTION
HANDLING PRECAUTIONS
ENVIRONMENTAL CONSIDERATIONS

EQUIVALENTCIRCUIT

Matrix Card Installation
Matrix Card Removal

INSTRUMENT AND DUT CONNECTIONS

Card Connectors

General Instrument Connections
Keithley Instrument Connections

Typical Test Fixture Connections
MATRIX EXPANSION
MAINFRAME CONTROL OF MATRIX CARD

Front Panel Matrix Control

............................

....................

........................

......................

.......................

...........................

...............

...............

...............

.........................

...................

...........

...........

........

............

.......

l-l
l-l
1-2
1-2

1-2
1-3
1-3
1-3
1-3
1-3

1-3
1-4

2-1
2-2
2-2
2-2

.

2-3
2-4

2-6
2-6
2-7
2-9

2.12
2-20
2-25
2-26
2-28

2.20

2.8.2

2.9

2.9.1

2.9.2

2.9.3

2.9.4

2.9.5

2.9.6

2.9.7

Matrix Control Over IEEE-488 Bus ...........

MEASUREMENTCONSIDERATIONS ..........

Magnetic Fields .........................

Radio Frequency Interference ..............

Ground Loops ..........................

Keeping Connectors Clean ................

Noise Currents Caused by Cable Flexing

Shielding ..............................

Guarding ..............................

SECTION 3 -Applications

......

2-33
2-35
2-35
2-36
2-37
2-38
2-39
2-39

2.41

3.1

3.2

3.2.1

3.2.2

3.3

3.3.1

3.3.2

3.3.3

3.3.4

3.3.5

3.3.6

3.3.7

3.4

INTRODUCTION ...........................

SEMICONDUCTOR TEST MATRIX ..............

System Configuration
Testing Common-Source Characteristic of FETs

RESISTIVITY TESTING USING MATRIX SWITCHING

IN A SMU TEST SYSTEM ......................

System Configuration ......................

Test Configuration .........................

Resistivity Calculations

Test Connections ..........................

Measurement Considerations

Pro

ram: Resistivity Tests Using a Switching Matrix

an Source Measure Unit ...................

d:

Program Description .......................

SMU REMOTE SENSING ......................

........... ;. .........

.....................

................

...

3-1
3-1
3-2
3-3

3-4
3-4
3-4
3-7
3-7
3-8

3-9
3-10
3-13

SECTION 4 - Service Information

4.1 INTRODUCTION . . . . .

4.2

4.3 PERFORMANCE VERIFICATION

4.3.1 Environmental Conditions . . . . 4-2

4.3.2 Recommended Test Equipment . . . . 4-2

HANDLING AND CLEANING PRECAUTIONS 4-1

4-l

4-2

4.3.3

4.3.4

4.3.5

4.3.6

4.3.7 Differential Isolation Verification

4.3.8

4.3.9

Special Connection Requirements
Offset Current Verification

Contact Potential Verification .
Path Isolation Verification .

Common Mode Isolation Verification

Path Resistance Verification

SECTION 5 - Replaceable Parts

4-4
4-7

4-9
4-l 1
4-14
4-17
4-19

5.1 INTRODUCTION .

5.2

5.3

5.4 FACTORY SERVICE . . . . .

5.5

PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ORDERING INFORMATION

COMPONENT LAYOUT AND SCHEMATIC DIAGRAM

3-l
3-l
3-l
3-1
3-1

List of Illustrations

SECTION 2

Figure 2-l

Figure 2-2

Figure 2-3

Figure 2-4

Figure 2-5
Figure 2-6
Figure 2-7
Figure 2-8
Figure 2-9
Figure 2-10
Figure 2-11
Figure 2-l 2
Figure 2-13
Figure 2-14
Figure 2-l 5

Figure 2-16
Figure 2-17
Figure 2-l 8
Figure 2-l 9
Figure Z-20
Figure 2-21

- Operation

Schematic of Model 7153 ..................

Card Installation in a Model 705 .............

Card Installation in a Model 706 ............

Model 7153 Connectors ...................

Miniature Connector Configuration ...........

Model 7153-TRX Pin Identification ...........

Triax Connector Configuration (Model 7153-TRX)

General Instrument Connections .............

Electrometer Connections ..................

Model 237 Source Measure Unit .............

Model 230 Voltage Source Connections .......

Model 220 Current Source Connections .......

Typical Test Fixture Connections .............

Equivalent Circuit of Test Fixture Connections ...
Typical Row Connections for Matrix Column

Expansion ..............................

Power Line Ground Loops ..................

Eliminating Ground Loops ..................

Shielding Example ........................

Dual Shielded Test Fixture ..................

Guarded Circuit .........................

Typical Guarded Signal Connections ..........

2-3
2-5
2-6
2-8

2-8
2-l 1
2-12
2-l 5
2-21
2-22
2-23
2-24
2-25
2-26

2-27
2-37
2-38
2-40
2-41
2-42
2-43

SECTUON 3 - Applications

Figure 3-1
Figure 3-2

Figure 3-3
Figure 3-4

Multi Unit Connections to Model 7153 . .
System Configuration for Measuring Common-

Source Characteristics
System Configuration for Resistivity Tests

Resistivity Test Configuration

3-2

3-3

3-5

3-5

Figure 3-5 Resistivity Measurement Conventions ..........

Figure 3-6 Test Connections for Resistivity Tests ...........

Figure 3-7 Program Flowchart ........................

Figure 3-8 Remote Sense and Guard Connections to Model

7153 ...................................

Figure 3-9 Remote Sensing with Guard .................

SECTION 4 - Service Information

3-6
3-8

3-l 1

3-14
3-15

Figure 4-l Signal-to-Guard Short Preparation .
Figure 4-2
Figure 4-3 Signal Terminal Extender
Figure 4-4
Figure 4-5 Contact Potential Testing .
Figure 4-6
Figure 4-7 Differential Input Isolation Testing
Figure 4-8

Figure 4-9 Path Resistance Testing . .

Coax to Banana Cable Preparation

Offset Current Testing

Path Isolation Testing

Common Mode Input Isolation Testing

......

......

.......

.......

.......

.......

.......

.......

4-5
4-6
4-7

4-8
4-10
4-12
4-15

4-18
4-21

list of Tables

SECTION 2 - Operation

Table 2-l Recommended Cables and Adapters
Table 2-2

Table 2-3 Three-digit ID Numbers for Programming

Table 2-4

Two-Digit ID Numbers for Programming
Model705

Model706
Most Often Used DDCs

2.10

Z-30

2.31
2-34

SECTION 4 - Service Information

Table 4-l

Table 4-2 Special Connection Parts ......................

Table 4-3 Path isolation 1.esting ........................ 4-14

Recommended Test Equipment ................. 4-3

4-5

SECTION 1 General Information

1 .l INTRODUCTION

This section contains general information about the Model 7153 High
Voltage Low Current Matrix Card and is arranged as follows:

1.2 Features

1.3 Warranty Information

1.4 Manual Addenda

1.5 Safety Symbols and Terms

1.6 Specifications

1.7 Unpacking and Inspection

1.8 Repacking for Shipment

1.9 Optional Accessories

1.2 FEATURES

Key features of the Model 7153 High Voltage Low Current Matrix Card in-

clude:

. 4 x 5 (four row by five column) switching matrix.

l

Low offset current for low-current measurements.

1-1

SECTION 1
General

Information

1.3 WARRANTY INFORMATION

Warranty information is located on the inside front coverofthis instruction

manual. Should your Model 7153 require warranty service, contact the
Keithley representative or authorized repair facility in your area for further
information. When returning the matrix card for repair, be sure to fill out
and include the service form at the back of this manual in order to provide

the repair facility with the necessary information.

1.4 MANUAL ADDENDA

Any improvements or changes concerning the matrix card or manual will
be explained in an addendum included with the the unit. Be sure to note
these changes and incorporate them into the manual before using or serv-

icing the unit.

1.5 SAFETY SYMBOLS AND TERMS

The following symbols and terms may be found on an instrument or used

in this manual.

The A
the operating instructions located in the instruction manual.

The
sent on the terminal(s). Use standard safety precautions to avoid personal
contact with these voltages.

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

The CAUTION heading used in this manual explains hazards that could
damage the matrix card. Such damage may invalidate the warranty.

1-2

symbol on an instrument indicates that the user should refer to

symbol on an instrument shows that 1 kV or greater may be pre-

i

General Information

SECTION 1

1.6 SPECIFICATIONS

Model 7153 specifications are located at the front of this manual. These

specifications are exclusive of the mainframe specifications, which are lo­cated in their respective instruction manuals.

1.7 UNPACKING AND INSPECTION

1.7.1 Inspection for Damage

Upon receiving the Model 7153, carefully unpack it from its shipping car­ton and inspect the card for any obvious signs of physical damage. Report
any such damage to the shipping agent immediately. Save the original

packing carton for possible future reshipment.

1.72 Shipment Contents

The following items are included with every Model 7153 order:

. Model 7153 Iiigh Voltage Low Current Matrix Card.

. Model 7153 Instruction Manual.

. Additional accessories as ordered.

1.7.3

If an additional instruction manual is required, order the manual package,
Keithley part number 7153-901-00. The manual package includes an in-

struction manual and any pertinent addenda.

Additional Instruction Manual

1.8 REPACKING FOR SHIPMENT

Should it become necessary to return the Model 7153 for repair, carefully

pack the unit in its original packing carton or the equivalent, and include

the following information:

. Advise as to the warranty status of the matrix card.

l-3

SECTION 1
General Information

l

Write ATTENTION REPAIR DEPARTMENT on the shipping label.

. Fill out and include the service form located at the back ofthis manual.

1.9 OPTIONAL CABLE ASSEMBLY

The following cable assembly is available to make connections to the
Model 7153.

Model 7153-TRX - This 2-meter cable assembly is made up of five indi­vidual triax cables. One end of the cable assembly is terminated with a
miniature, multiple-contact plug that will mate to the matrix card recepta­cles. The other end of the cable assembly is terminated with five 3.slot
male triax connectors.

NOTE

Adapters that are available from Keithley are listed in Table

2-1.

l-4

SECTION 2 Operation

2.1 INTRODUCTION

This section contains information on aspects of matrix card operation and

is arranged as follows:

2.2 Handling Precautions: Details precautions that should be observed

when handling the matrix card to ensure that its performance is not de-

graded due to contamination.

2.3 Environmental Considerations: Outlines environmental aspects of
using the Model 7153.

2.4 Equivalent Circuit: Provides the simplified matrixcard circuitforthe
Model 7153.

2.5 Card Installation and Removal: Covers the basic procedures for in­stalling and removing the matrix card from the Model 705 or 706 main-

frame.

2.6 Connections: Discusses card connectors, cables and adapters, and
typical connections to other instrumentation and DUT test fixtures.

2.7 Matrix Expansion: Shows how to expand the matrix by connecting
two or more matrix cards together.

2.8 Mainframe Control of Matrix Card: Covers the operating aspects
specific to the Model 71 S3.

2.9 Measurement Considerations: Reviews a number of considerations
when making low-level measurements.

2-1

SECTION 2

Operation

2.2 HANDLING PRECAUTIONS

To maintain high impedance isolation, care should be taken when han­dling the matrix card to avoid contamination from such foreign materials
as body oils. Such contamination can substantially lower leakage resis­tances, degrading performance.

To avoid possible contamination, always grasp the card by the side edges.

Do not touch the edge connectors of the card and do not touch board sur­faces or components. When not installed in a mainframe, keep the card in
the bag and store in the original packing carton.

Dirt build-up over a period of time is another possible source of contami­nation. To avoid this problem, operatethe mainframe and matrix card only

in a clean environment.

If the card should become contaminated, it should be thoroughly cleaned
as explained in paragraph 4.2.

2.3 ENVIRONMENTAL CONSIDERATIONS

For rated performance, the card should be operated within the tempera­ture and humidity limits given in the specifications at the front of this man­ual. Note that current offset and path isolation values are specified within a

lower range of limits than the general operating environment.

2.4 EQUIVALENT CIRCUIT

A simplified schematic of the Model 7153 4 x 5 matrix card is shown in
Figure 2-I. Each ofthe 20 crosspoints is made up of a two-pole switch. In
this simple configuration any row can be connected to any column by
closing the appropriate crosspoint. Mainframe control of matrix
crosspoints is covered in paragraph 2.8.

2-2

SECTION 2

Operation

r­I
I
I
I

1)

I
I

2>

’ now

3>

I

4)

I
I
I
I

I--

Figure 2-1. SchematicofModel7753

-

A diagram of the Model 7153 is provided in Appendix A. This
system configuration worksheet makes it convenient to plan a
matrix system. Additional space is provided for drawings and

notes.

__--------

Column

1 2 3 4 5

“2

97

NOTE

-1
I
I
I
I
I
I
I

I
I
I
I
I
I

- _I

2.5 CARD INSTALLATION AND REMOVAL

The following procedures explain how to install and remove the Model
7153 matrix card from the Models 705 and 706 mainframes.

WARNING
To prevent electrical shock which could result in injury or
death, turn off the mainframe power and disconnect the line

cord before installing or removing matrix cards. If there are

2-3

SECTION 2

Ooeration

cables connected to the card, also remove power from those
circuits before proceeding.

CAUTION

Contamination will degrade the performance of the matrix

card. To avoid contamination, always grasp the card by the
side edges. Do not touch the board surfaces or components.

2.5.1

Perform the following procedure to install the Model 7153 Imatrix card in
either the Model 705 or Model 706 mainframe. Refer to Figure 2-2 to in­stall the card in the Model 705 and refer to Figure 2-3 to install the card in
the Model 706.

1.

2.

3.

Matrix Card Installation

Slidethe card into the desired slot as shown in the appropriate illustra-

tion. Make surethe card edges ofthe bottom shield board are properly

aligned with the grooves in the receptacle.
Once the card is almost all the way in the slot, and you encounter re­sistance, push firmly on the edge of the card to seat it in the edge con­nector.

Once the card is fully seated, lock the card in place by placing the

latches in the locked position.

2-4

SECTION 2

ODeration

Figure 2-2. Card lnstahtion in a Model 705

-

2-5

SECTION 2
Operation

‘igure 2-3.

2.5.2

To remove the matrix card, first unlock it by pulling the latches outward,

then grasp the end of the card at the edges, and pull the card out of the

mainframe.

2.6

The information in the following paragraph explains how to connect the
matrix card to external test circuitry (instruments and DUTL

2-6

INSTRUMENT AND DUT CONNECTIONS

Card hstaallation in a Model 706

Matrix Card Removal

SECTION 2

Operation

CAUTION

Do not connect the matrix card to unlimited power circuits.
This product is intended for use with impedance limited
sources. Do not connect directly to AC mains.

When connecting an impedance limited source, install appro­priate protection (such as a fuse or a clamping circuit) to limit
potentially damaging fault currents to the matrix card.

CAUTION

Contamination will degrade the performance of the matrix

card. To avoid contamination, always grasp the card by the

side edges. Do not touch the board surfaces or components.

Card connectors, recommended cables and adapters, and typical connec­tions to instruments and DUT are discussed in the following paragraphs.

2.6.1 Card Connectors

The card connectors are shown in Figure 2-4. There are two miniature co­axial, multiple contact receptacles. One ofthe receptacles is used for row
connections and the other is used for column connections. Row and col­umn number designations are included in the illustration. Notice that one
contact of each receptacle is reserved for chassis ground. For each coaxial
connector, as shown in Figure 2-5, the center conductor is SIGNAL, and
the outer shell (shield Iis GUARD.

2-7

SECTION 2
Operation

Note : Numbers indicate row and column paths.

Tzure 2-4. Model 7753 Connectors

&;a.;”

Max

Chassis Ground Connector

(1 Of 2)

IL----!

Warning : Do not exceed maximum

voltage levels shown.

t ‘igure 2-5. Miniature Connector Configuration

2-8

13oov

Max

SECTION 2

Operation

WARNING

Do not exceed 200V behveen SIGNAL and GUARD, or 13OOV
between SIGNAL and chassis ground, or behveen GUARD
and chassis ground or between paths (see Figure 2-5). Also,
do not exceed IA carry/500mA switched, 1OVA peak (resis­tive load).

CAUTION
To prevent damage to the matrix card and other equipment,
do not connect equipment such that they short out on the

same row or column.

2.6.2 Recommended Cables and Adapters

Table 2-1 summarizes the cables and adapters recommended for use with
the Model 7153.

NOTE

Equivalent user-supplied items may be substituted as long as
they are of sufficient quality (low offset current, high leakage
resistance). Using substandard cables and adapters may de­grade the integrity of the measurements made using the matrix
card. See paragraph 2.9 for a discussion of measurement con­siderations.

The following discussion provides additional information about the rec­ommended Keithley cable; Model 7153.TRX cable.

2-9

SECTION 2
Operation

Table 2-l. Recommended Cables and Adapters

Manufac-

tern

turer

­1

Keithley

2

Keithley 6172

Keithley

Keithley 237-TRX-T

Keithley

Model or
Part No.

7153.TRX

237~BAN-3

Descriotion Applications
Matrix to triax

cable put connections

2.slot male to
3-lug female
triax adapter

3-14 female
to female triax
barrel male triax cable

3-&t male to
dual 3-lug tions for
female

3-slot triax to
male banana

plup

‘6172 is for use in low voltage kC5OOVrms) applications only.

7153 input/out-

Connect 3-slot
triax cable to
2-1~~ triax con­nector

Connect male
triax cable to

Dual connec-

7153.TRX

Banana plug ca­ble

Model 7153-TRX Low Noise Matrix to Triax Cable

TheModel 7153-TRX is a 2-m&r cableassembly that is terminated with a
miniature coaxial, multiple contact plug at one end, and five 3-slot male
triax connectorsat the other end. The plug end of the cable will mate to the
ROW and COL receptacles of the matrix card. The triax connectors will
mate to standard 3-lug female triax connectors. Each triax cable is labeled
and corresponds to a ROW or COL as follows:

2-10

SECTION 2

Operation

Triax #II = Row 1 or Column 1
Triax #t2 = Row 2 or Column 2
Triax lt3 = Row 3 or Column 3
Triax $14 = Row 4 or Column 4
Triax +#5 = Column 5

On each triax connector, as shown in Figure 2-7, the center conductor is
SIGNAL, the inner shield is GUARD, and the connector shell is connected
to the outer shield of the cable. Note that this outer shield is connected to
chassis of the Model 7153.

Pill designations
molded on plug
housing

Pill

Designation

1

F

Figure 2.6.

-

Matrix Card

ROW or Column

Model 7753.TRX Pin

Note : Pin designations 1, 2. 4. 5 and 6

iv3 coaxial co”“octor~. Pill 3 is
a s,nc$e ,,I” connector for chassis
ground.

identification

2-11

SECTION 2

Ooeration

Signal

7153
Chassis
Ground

Warning : Do not exceed maximum

voltage levels shown.

Figure 2-7. Trim Connector Configuration (Model 71.53-TRN

2.6.3

The following paragraphs discuss connecting the Model 7153 to various
general classes of instrumentation such as DMMs, electrometers, sources,
and source/measure units. Because these configurations are generic in na­ture, some modification of the connecting schemes may be necessary for
your particular instrumentation. Also, special cables or adapters may be
necessary.

Figure 2-8 shows the general instrument connections for the discussions

below. Note that DUT guarding or shielding is not indicated here; see

Figure 2-18 and Figure 2-21 for shielding and guarding information. As
shown, all figures assume instruments are connected to rows, and the DUT
is connected to columns.

General Instrument Connections

WARNING

Do not use coaxial cables and adapters because hazardous
voltage from guard sources may be present on the cable
shields.

2-12

SECTION 2

Ooeration

DMM Connections

General DMM connections are shown in Figure 2-13(A), @I, and (Cl. Float­ing connections are shown in (A), with LO and HI routed to two separate
rows on the Model 7153. The common LO connections in (5) should be
used only for non-critical applications becausethe performance (isolation)
of the GUARD pathway is not as good as a SIGNAL pathway.

WARNING

Hazardous voltage from other guard sources may be present

on LO or the DUT if other crosspoints are closed.

Four-wire DMM connections are shown in Figure 2-K). In this case, a to­tal of four rows are required; one row for HI, one for LO, one for SENSE HI,
and one for SENSE LO.

Electrometer Connections

Typical electrometer connections are shown in Figure 2-8(D) through (G).
The unguarded volts connections in (Dl show the HI signal path routed to
one row, and the LO path goes to a another row. Both GUARD pathways
are connected to electrometer LO. For guarded voltage (E), Model 7153
GUARD is connected to electrometer GUARD.

The connections for electrometer fast amps and resistance measurements

are shown in Figure 2-8(F) and (CL These configurations are essentially the
same as those discussed above. In the case of fast amps, both GUARD
paths are connected to electrometer LO, while in the case of guarded resis­tance, one GUARD path is connected to electrometer GUARD, and the
other GUARD path is connected to electrometer LO.

Source Connections

Voltage and current source connections are shown in Figure 2-O(H)

through (J). The HI and LO paths of the voltage source (H) are routed

through two rows, with both card GUARD pathways connected to voltage
source LO. For the unguarded current source connections (I), card

2-13

SECTION 2

Oneration

GUARD is again connected to source LO, with source HI and LO routed

through two rows. In the case of the guarded current source in (I), card

GUARD of the HI signal path is connected to source GUARD, and the
other GUARD path is connected to source LO.

Source/Measure Unit Connections

Figure 2-8(K) shows typical connections for a source/measure unit (SMU).

In this instance, a remote-sensing type of a SMU is shown, requiring a total
of four signal pathways to the DUT. For critical measurements, both
source and sense HI pathways would be guarded as shown, with two of the
four card GUARD pathways connected to SMU GUARD terminals. As
with other instrument connections, the LO card GUARD pathways are
connected to SMU LO terminals.

2-14

SECTION 2

Ooeration

2-15

SECTION 2

Operation

General Instrument Connections (Cont.)

2-16

I/h /?!I
i----J

G., Elecmnelei, ReSlslanCB (Guarded)

General Instrument Connections (Cont.)

x63

2-17

SECTION 2

Operation

2-l 8

SECTION 2

Operation

2-19

SECTION 2
Operation

2.6.4 Keithley Instrument Connections

The foollowing paragraphs outline connecting typical Keithley instruments

to the Model 7153 High Voltage Low Current Matrix Card. Other similar
instruments can be connected using the same cabling as long as their in­put/output configurations are the same. Instrument connections covered

include:

. Model 617 Electrometer/Source
. Model 237 High Voltage Source Measure Unit
. Model 230 Programmable Voltage Source

l

Model 220 Programmable Current Source

NOTE

The following figures show instruments connected to matrix

rows. Keep in mind that they could just as well be connected to
matrix columns. Also, it doesn’t matter which rows (or col­umns) are used since the row/column specifications are uni­form.

WARNING

To

prevent

not

apply power

Model 617 Electrometer Connections

Connections for the Model 617 Electrometer are shown in Figure 2-9 and
are described as follows:

1, Connect the matrix end of the Model 7153-TRX cable assembly to

ROW of the Model 7153.

2. Connect the Model 6172 2-slot male to 3-lug female triaxial adapter
to the INPUT of the Model 617.

3. Connect Row 1 of the Model 7153.TRX cable assembly to the triax

adapter on the INPUT of the Model 617.

4. Connect three 3-lug female to female triax adapters (item 3 in
Table 2-l) to the three t&x/banana cables (Model 237-BAN-3)..

5. Connect the triax adapter end of a triax/banana cable to Row 2 of the
Model 7153-TRX, and connect the banana end of the cable to the

Z-20

electric shock that could cause injury or death, do

to cables that are not connected.

SECTION 2

Oneration

COM terminal oftheModel617,Theshorting IinkbetweenCOM and
chassis ground should be removed for this application.

6. Set the Model 617 GUARD switch to the OFF position.

7. Connect the triax adapter end of the other two triaxfbanana cables to
Rows 3 and 4 of the Model 7153.TRX cable assembly, and connect

the banana ends of the cables to the V-SOURCE l-11 and LO terminals

of the Model 617

Figure 2-9. Electrometer Connections

Model 237 Source Measure Unit Connections

Connectthe Model 237 orothersimilar Source Measure Unit to the matrix

card as shown in Figure 2-10. This configuration for four-terminal meas­urements is similar to the one shown in Figure 2-8K.

2-21

SECTION 2

Operation

Figure 2- 10. Model 237Source Measure Unit

WARNING
For high voltage testing, DUT should be installed in an inter­locked, safety earth grounded test fixture, such as the Keithley
Model 8006. To avoid electrical shock, be sure to connect the
interlock cable from the Source Measure Unit to the test fix-

ture.

Model 230 Voltage Source Connections

Referring to Figure 2-I 1, connect the Model 230 OUTPUT and COM­MON terminals to the desired rows using two Model 237-BAN-3 cables
and two Model 237.TRX-BAR adapters.

2.22

SECTION 2

Operation

For remote sensing applications, the SENSE OUTPUT and SENSE COM­MON terminals of the Model 230 can be connected to the two remaining

rows using the same cabling method.

0gure 2- 11. Model 230 Voltage Source Connections

Model 220 Current Source Connections

The Model 220 Current Source can be connected to the matrix card as

shown in Figure 2-12.

1, Connect the matrix end of the Model 7153-TRX cable assembly to

ROW of the Model 7153.

2. Connect the Model 6172 (item 2 in Table 2-l )2-slot male to 3.lug fe-

male triaxial adapter to the Model 220.

2-23

SECTION 2

Operation

Figure 2- 12. Mode/ 220 Current Source Connections

3. Connect Row 1 of the Model 7153-TRX cable assembly to the 6172
triax adapter.

4. Connect a 3-lug female to female triax adapter to the G&banana ca-

ble.

5. Connect the triax adapter end of the triadbanana cable to Row 2 of
the Model 7153-TRX, and connect the banana end of the cable to the
OUTPUT COMMON jack of the Model 220.

NOTE

,The configuration shown allows common to be individually

switchec i (ROW 2). Thus, do not connect ROW1 Guard of the
matrix card (which is also common) to a DUT.

2-24

SECTION 2

Ooeration

2.6.5 Typical Test Fixture Connections

Typically, a test fixture will be connected to desired columns of the Model

7153. Normally, the test fixture will be equipped with 3&g female triax
connectors to facilitate the use of the Model 7153.TRX cable assembly.

These typical test fixture connections are shown in Figure 2-13

Figure 2- 13. Typical

Do not use BNC cables and adapters because hazardous volt­ages from guard sources could be present on the BNC cable
shields.

Internally, the test fixture should be wired as shown in the equivalent cir­cuit of Figure 2-14. SIGNAL isconnected totheprobeorotherdevicecon-

tact points, while GUARD is carried through as close to the device as pos-

sible. If coaxial probes are to be used, connect GUARD to the probe shield
if the probe shield is insulated from the fixture shield.

To provide protection from shock hazards, the test fixture

chassis must be properly connected to a safety earth ground.

A grounding wire (IO AWC or larger) must be attached se-

curely to the test fixture at a terminal designed for safety

rounding (the terminal should be marked with the symbol

& ). The other end of the grounding wire is then attached to a

8

Jest

Fixhire Connecrions

WARNING

WARNING

2-25

known safety earth ground, such as a cold water pipe, or a
grounded electrical outlet box.

Figure 2-14.

Equivalent

Circuit of Test Fixture Connections

2.7 MATRIX EXPANSION

A matrix can be expanded by connecting two or more Model 7153 matrix

cards together. A single matrix card consists of 20 crosspoints. Thus, each

additional matrix card increases the matrix by 20 crosspoints. Connecting
the rows or one matrix card to the rows of another matrix card increases
thenumberofmatrixcolumns.Connectingthecolumnsofonematrixcard
to the columns of another matrix card increases the number of matrix

rows.

Matrix Expansion Connections

Model 7153.TRX cables along with the appropriate adapters can be used
for matrix expansion. Typical row connections of two matrix cards (which
will increase the available matrix columns to IO) are shown in Figure 2-l 5.
The rows of the two matrix cards are connected togehter via four Model
237-TRX-T adapters. The Model 237-TRX is a high voltage 3-&t male
triax to dual 3-lug female triax adapter. Standard 3-slot triax cables (such
as the Model 7078.TRX) from the instrumentation or DUT test fixture will

2-26

SECTION 2

Ooeration

mate to the male end of the 9”’ adapters via four Model 237-TRX-BAR
adapters.

To connect the rows of more matrix cards, simply use additional Model

237-TRX-T adapters. Each additional matrix card will require four “T”
adapters.

Column connections, which increase matrix rows, are made in a similar

fashion. The only difference is that the Model 7153.TRX cables are instead

connected to the COL connectors on the matrix card.

Figure 2-15. Typical Row Connections for Matrix Column Expansion

2-27

SECTION 2

Operation

2.8 MAINFRAME CONTROL OF MATRIX CARD

The information in the following paragraphs does not includeoperation of
the Model 705 or 706 mainframe. That information is provided in the re­spective mainframe instruction manuals. The following deals primarily

with programming information specific to controlling the Model 7153.

Whether from the front panel or over the IEEE-498 bus, matrix control is
simply a matter ofclosing and opening the appropriate matrix crosspoints.
Crosspoint assignment numbers for a Model 7153 card are determined by

its installed position (card number) in a mainframe. For daisy chain opera­tion, the position of the mainframe in the system is also a determining fac­tor. The following paragraphs explain how to determine crosspoint assign-

ment numbers.

2.8.1 Front Panel Matrix Control

Using the Model 7153 matrix card with an appropriate Keithley main­frame (Model 705 or 706) requires that the matrix mode be selected. To

place the mainframe in the matrix mode from the front panel, perform the

following steps:

1. Select Program 6 by pressing the PRCM key and then the number 6
key.

2. Press the 0 key and then the ENTER key.

After the ENTER key is pressed, the mainframe is placed in the matrix mode
of operation.

With the mainframe in the matrix mode, the display format is as follows:

For the Model 705:

mmnx

where: “mm n” is the crosspoint assignment number.

2-28

SECTION 2

Operation

mm = 2-digit ID number from 01 to 50. This number identifies the main­frame and slot that the card is located in and also indicates the matrix card
column number.

n = Matrix card row from 1 to 4.

x denotes the status of the crosspoint. An 0 indicates that the crosspoint is
open, while a C indicates that the crosspoint is closed.

For the Model 706:

mmmnx

where: “mmm n” is the crosspoint assignment number

mmm = 3-digit ID number from 001 to 250. This number identifies the

mainframe and slot that the card is located in and also indicates the matrix
card column number.

n = Matrix card row from 1 to 4

x denotes the status of the crosspoint. An 0 indicates that the crosspoint is
open, while a C indicates that the crosspoint is closed.

In general, controlling the matrix from the front panel consists of display-

ing the desired matrix crosspointassignment number and closing (or open-

ing) the crosspoint relay. Table 2-2 and Table 2-3 provide the two-digit
(for Model 705) and three-digit (for Model 706) ID numbers that make up
the “m” portion of the crosspoint assignment number.

2-29

SECTION 2
Operation

Table 2-2. Two-Digit ID Numbers for Programming

Model 705

Model

705

Card Slot
Location

Master

Slave #1

Slave #2

Slave #3

Slave #4

Card 1 01
Card 2 06

Card 1 11
Card 2 16

Card 1 21

Card 2 26
Card 1 31

Card 2 36
Card 1 41

Card 2 46 47

I

-

02
07

12
17

22
27

32 33
37

42

03
08 09

13
18 19

23

28

38

43
48

04

14

24
29

34
39

44
49

05

10

15
20

2s
30

35

40
45

50

2-30

SECTION 2

Oaeration

Table 2-3. Three-dieit ID Numbers for Proeramminc!

Model 766

Model

706

Master

&we #l

;lave #2

Card Slot

location

Card 1
Card 2 006 007 008 009 010
Card 3 011 012 013 014 015
Card 4 016 017 018
Card 5
Card 6
Card 7
Card 8 036 037 038 039 040
Card 9
Card 10

Card 1 051 052
Card 2 056 057 058
Card 3
Card 4
Card 5 071 072 073
Card 6 076 077 078
Card 7 081
Card 8
card Y 091 092 093 094
Card10 096 097 098 099 100

Card 1
Card 2
Card 3
Card 4
Card 5
Card 6
Card 7
Card 8
Card 9
Card 10

Mat&&,&&Cardn

1 2 3

001 002 003 004 005

019 020
021 022 023 024 025
026
031 032 033 034 035

041
046 047 048 049 050

061 062 063 064 065
066

086 087 088 089 090

101 102
106 107
111 112
116 117
121 122
126
131 132
136 137
141 142
146 147

- -

027

042

067

082 083 084 085

127

028 029 030

043 044 045

053 054 055

059 060

068 069 070

074 075

079 080

103
108
113

118

123
128
133

138

143

148

-

104

109 110

114

119

124

129 130

134 135

139 140

144

149 150

- - L

5

095

105
115

120
125

145

2-31

SECTION 2

Operation

Three-digit ID Numbers for Programming Model 706 (Cont.)

Model

706

ilave #3

ilave #4

Card Slot

T

Location

Card 1
Card 2
Card 3
Card 4
Card 5
Card 6
Card 7
Card 8
Card 9
Card 10

Card 1
Card 2
Card 3
Card 4
Card 5
Card 6
Card 7
Card 8
Card 9
Card 10

151 152 153 154
156
161 162 163
166 167 168
171 172
176 177 178
181 182 183 184
186 187 188 189
191 192 193
196 197 198

201 202 203 204
206 207 208 209
211 212 213 214
216
221 222 223 224
226 227 228
231 232 233 234
236 237
241 242 243 244
246

- - - -

157 158 159

164
169

173 174

179

194
199

217 218 219

229

238

247 248 249

239

155
160
165
170
175
180
185
190
195

200
205

210
215
220
225
230
235
240
245
250

-

Example #l -In a single card system, program the mainframe (Model 705
or 706) to close Row 3, Column 4 of a matrix card installed in the Card 1
slot of the mainframe.

1. From Table 2-2 or Table 2-3, it can be determined that the required ID
number is 04 (for the Model 705) or 004 (for the Model 706).

2. From the given information, the row number is 3. Thus, thecrosspoint
assignment number is either 04 3 (for the 705) or 004 3 (for the 706).

3. On the mainframe, use the CHANNEL key to display the crosspoint
assignment number (04 3 or 004 3).

4. Close the crosspoint relay by pressing the CLOSE key on the main­frame.

2-32

SECTION 2

Ooeration

Example #2 - In a multi-mainframe system, program the Master main­frame (Model 705) to close Row 2, Column 4 of a matrix card installed in
the Card 2 slot of Slave #3 mainframe.

1. From Table 2.2, it can be determined that the required two-digit ID
number is 39.

2. From the given information, the row number is 2. Thus, the crosspoint
assignment number is 39 2.

3. On the Master mainframe, use the CHANNEL key to display the num­ber 39 2.

4. Close the crosspoint relay by pressing the CLOSE key on the Master
mainframe.

Example #3 - In a multi-mainframe system, program the Master main­frame (Model 706) to close Row2, Column 4 of a matrix card installed in
the Card 2 slot of Slave #3 mainframe.

1. From Table 2-3, it can be determined that the required three-digit ID
number is 159.

2. From the given information, the row number is 2. Thus, the crosspoint
assignment number is 159 2.

3. On the Master mainframe, use the CHANNEL key to display the num­ber 159 2.

4. Close the crosspoint relay by pressing the CLOSE key on the master
mainframe.

2.8.2

The most often used IEEE-488 device-dependent commands (DDCs) used
to operate the Model 7153 are summarized in Table 2-4. For a complete

listing and detailed explanation of the commands, see the appropriate
mainframe instruction manual.

Matrix Control Over IEEE-488 Bus

NOTE
Operation over the bus is somewhat analogous to front panel
operation. Thus, to fully understand the information in this
paragraph, make sure that front panel operation, as explained
in the preceding paragraph, is understood.

2-33

SECTION 2

Ooeration

Table 2-4. Most Often Used DDCs

Function

Select matrix mode

Bmmn Bmmmn
Cmmn Cmmmn
Nmmn Nmmmn

L-L

Note: mmn and mmmn are crosspoint assignment num­bers (see paragraph 2.8.1).

Basically, control over the bus consists offirst placing the mainframe in the
matrix mode (A0 command) and then closing or opening the desired
crosspoint using the C or N command respectively. The B command is
used to display the crosspoint and its status (open or closed).

Thefollowingprogrammingexamples use HP4.0 BASIC. Also, Thefollowingprogrammingexamples use HP4.0 BASIC. Also,
they assume an IEEE address of 17 for the Model 705 and an they assume an IEEE address of 17 for the Model 705 and an

address of 18 for the Model 706. address of 18 for the Model 706.

Example #l

frame from (Model 705) over the IEEE bus to close Row 1, Column 5 of a

matrix card installed in the Card 1 slot of Slave #4 mainframe.

1. From Table 2-2 it can be determined that the required two-digit ID
number is 45.
From the given information, the row number is 1. Thus, thecrosspoint

2.
assignment number is 45 1.

Enter the following programming statements into the HP computer:

3.

- In a multi-mainframe system, program the master main-

Display crosspoint number
Close crosspoint
Open crosspoint

I

NOTE NOTE

2-34

REMOTE

OUTPUT 717: “AOX”

OUTPUT

OUTPUT 717; “C451 X”
OUTPUT 717; “N45, X”

717

717: “6451 X”

SECTION 2

Operation

The second statement places the master Model 705 in the matrix mode.
The third statement displays crosspoint 45 1 and its current status (open or
closed). The fourth statement closes crosspoint 45 1, and the last statement
opens crosspoint 45 1.

Example

frame (Model 706) from over the IEEE bus to close Row 4, Column 1 of a

matrix card installed in the Card 8 slot of Slave #4 mainframe.

1. From Table 2-3 it can be determined that the required three-digit ID

2. From the given information, the row number is4. Thus, the crosspoint

3. Enter the following programming statements into the HP computer:

The second statement places the master Model 706 in the matrix mode.
The third statement displays crosspoint 236 4 and its current status (open
or closed). The fourth statement closes crosspoint 236 4, and the last state-

ment opens crosspoint 236 4.

2.9

Many measurements made with the Model 7153 concern low-level sig-

nals. Such measurements are subject to various types of noise that can seri­ously affect low-level measurement accuracy. The following paragraphs
discuss possible noise sources that might affect these measurements.

#2 - In a multi-mainframe system, program the master main-

number is 236.

assignment number is 236 4.

REMOTE 718
OUTPUT 718; “AOX”
OUTPUT 718; “82364X”
OUTPUT 718; %2364X”
OUTPUT 718; “N2364X”

MEASUREMENT CONSIDERATIONS

2.9.1

When a conductor cuts through magnetic lines of force, a very small volt­age is generated. This phenomenon will frequently cause unwanted sig-

nalstooccurin thetest leadsofaswitchingmatrixsystem. Iftheconductor

Magnetic Fields

2-35

SECTION 2

Operation

has sufficient length, even weak magnetic fields like those of the earth can
create sufficient signals to affect low-level measurements.

Two ways to reduce these effects are: (1) reduce the lengths of the test

leads, and (2) minimize the exposed circuit area. In extreme cases, mag­netic shielding may be required. Special metals with high permeability at
low flux densities (such as mu metal) are effective at reducing these effects.

Even when the conductor is stationary, magnetically-induced signals may
still be a problem. Fields can be produced by various signals such as the

AC power line voltage. Large inductors such as power transformers can

generate substantial magnetic fields, so care must be taken to keep the
switching and measuring circuits a good distance away from these poten-

tial noise sources.

2.9.2 Radio Frequency Interference

RFI (Radio Frequency Interference) is ageneral term used to describe elec­tromagnetic interference over a wide range of frequencies across the spec­trum. Such RFI can be particularly troublesome at low signal levels, but

can also affect measurements at high levels if the problem is of sufficient

severity.

RFI can be caused by steady-state sources such as radio or TV signals, or

some types of electronic equipment (microprocessors, high speed digital

circuits, etc.), or it can result from impulse sources, as in the case of arcing

in high-voltage environments. In either case, the effect on the measure-

ment can be considerable if enough of the unwanted signal is present. A

common problem is the rectification by semiconductor junctions of RF

picked up by leads.

RFI can be minimized in several ways. The most obvious method is to keep
the equipment and signal leads as far away from the RFI source as possible.
Shielding the matrix switching card, signal leads, sources, and measuring

instruments will often reduce RFI to an acceptable level. In extreme cases,
a specially-constructed screen room may be required to sufficiently at­tenuate the troublesome signal.

2-36

SECTION 2

Ooeration

Many instruments incorporate internal filteringthat may help to reduce RFI
effects in some situations. In some cases, additional external filtering may
also be required. Keep in mind, however, that filtering may have detrimen­tal effects on the desired signal.

2.9.3

When two or more instruments are connected together, care must be taken
to avoid unwanted signals caused by ground loops. Ground loops usually
occur when sensitive instrumentation is connected to other instrumenta­tion with more than one signal return path such as power line ground. As
shown in Figure 2-16, the resulting ground loop causes current to flow

through the instrument LO signal leads and then back through power line

ground. This circulating current develops a small but undesirable voltage
between the LO terminals of the two instruments. This voltage will be

added to the source voltage, affecting the accuracy of the measurement.

Ground Loops

Figure 2- 16. Power Line Ground Loops

Figure 2-17 shows how to connect several instruments together to elimi­nate this type of ground loop problem. Here, only one instrument is con­nected to power line ground.

Ground loops are not normally a problem with instruments having isolated

LO terminals. However, all instruments in the test setup may not be de­signed in this manner. When in doubt, consult the manual for all instru­mentation in the test setup.

2-37

SECTION 2
Operation

2.9.4 Keeping Connectors Clean

As is the case with any high-resistance device, the integrity of coaxial, tri­axial and other connectors can be damaged if they are not handled prop­erly. If the connector insulation becomes contaminated, the insulation re­sistance will besubstantially reduced, affecting high-impedance measure­ment paths.

Oils and salts from the skin can contaminate connector insulators, reduc-

ing their resistance. Also, contaminants present in the air can be deposited
on the insulator surface. To avoid these problems, never touch the connec­tor insulating material. In addition, the matrix card should be used only in
clean, dry environments to avoid contamination.

If the connector insulators should become contaminated, either by inad­vertent touching, or from air-borne deposits, they can be cleaned with a
cotton swab dipped in clean methanol. After thorough cleaning, they
should be allowed todryfor several hours in a low-humidity environment
before use, or they can be dried more quickly using dry nitrogen.

2-38

SECTION 2

ODeration

2.9.5

Noise currents can be generated by bending or flexing coaxial or triaxial
cables. Such currents, which are known as triboelectric currents, are gen­erated by charges created between a conductor and insulator caused by
friction,

Low-noise cable can be used to minimize these effects. Such cable has a
special graphite coating under the shield to provide lubrication and to pro­vide a conduction path to equalize charges.

Even low-noise cable generates some noise currents when flexed or sub­jected to vibration. To minimize these effects, keep the cables as short as
possible, and do not subject them to temperature variations that could
cause expansion or contraction. Tie down offending cables securely to
avoid movement, and isolate or remove vibration sources such as motors
or pumps.

Noise Currents Caused by Cable Flexing

2.9.6 Shielding

Proper shielding ofall unguarded signal paths and devices under test is im­portant to minimize noise pickup in virtually any switching matrix system.
Otherwise, interference from such noise sources as line frequency and RF
fields can seriously corrupt a measurement.

In order for shielding to be effective, the shield surrounding the HI signal
path should be connected to signal LO for chassis ground for instruments
without isolated LO terminals). Since most Model 7153 matrix applica-

tions call for separately switching LO, a separate connection from LO to
the cable shield at the source or measurement end must be provided, as in
the example of Figure 2-18. Here, we are using the GUARD path of the

Model 7153 to carry the shield out to the device under test. Needless to
say, this arrangement should not be used with guarding, as GUARD and
LO should not be connected together.

2-39

SECTION 2

Ooeration

Figure Z- 10. Shielding Example

WARNING
Hazardous voltage may be present if LO on any instrument is
floated above ground potential.

lfthe device under test is to be shielded, the shield should be connected to

the LO terminal. If you are using the GUARD connection as shield, care

should be taken to insulatethe outer ring ofthe triaxial connector mounted
on the test fixture from the test fixture itself. Otherwise, LO will be con­nected to earth ground, possibly resulting in a ground loop. An alternative

is to use two shields, one mounted within (and insulated from) the other. In
this case, the GUARD path would be connected to the inner shield, while
the outer shield would be earth grounded. This arrangement is shown in

Figure 2-l 9. Incidentally, this configuration is also recommended for
guarded applications, with the inner shield as guard, and the outer shield

acting as a safety shield.

2-40

SECTION 2

Operation

Figure

2-I 9. Dual Shielded

Test

Fixture

2.9.7 Guarding

Guarding is important in high-impedance circuits where leakage resis­tance and capacitance could have degrading effects on the measurement.
Guarding consists of using a shield surrounding a conductor that is carry-

ing the high-impedance signal. This shield is driven by a low-impedance

amplifier to maintain the shield at signal potential. For triaxial cables, the

inner shield is used as guard.

Guarding minimizes leakage resistance effects by driving the cable shield
with a unity-gain amplifier, as shown in Figure 2.20. Since the amplifier
has a high input impedance, it minimizes loading on the high-impedance

signal lead. Also, the low output impedance ensures that the shield re­mains at signal potential, so that virtually no leakage current flows through

the leakage resistance, RL. Leakage between inner and outer shields may be

considerable,butthatleakageisofIittleconsequencebecausethatcurrentis
supplied by the buffer amplifier rather than the signal itself.

In a similar manner, guarding also reduces the effective cable capacitance,
resulting in much faster measurements on high-impedance circuits. Be­cause any distributed capacitance is charged through the low impedance
of the buffer amplifier rather than by the source, settling times are short­ened considerably by guarding.

2-41

SECTION 2

Operation

2-20. Guarded

Figure

In order to use guarding effectively with the Model 7153, the GUARD path
of the matrix card should be connected to the guard output of the sourcing
or measuring instrument. Figure 2-21 shows typical connections. Guard
should be properly carried through the inner shield to the device under test
to be completely effective. The shielded, guarded test fixture arrangement
shown in Figure 2-19 is recommended for safety purposes (guard voltage

may be hazardous with some instruments). With most instruments, special
adapters or cables may be required to connect guard to the inner shield,
and at the same time route signal LO through a separate cable.

Circuit

2-42

Figure 2-2 I, Typical Guarded Signal Connections

SEC J/ON 2

Operation

2-43

SECTION 3

Applications

3.1 INTRODUCTION

This section covers typical applications for the Model 7153 High Voltage

Low Current Matrix card and is organized as follows:

3.2 Semiconductor Test Matrix: Details a semiconductor test matrix
that can be used to perform a variety of different tests on semiconductors
such as FETs.

3.3 Resistivity Testing Using Matrix Switching in a SMU Test System:
Covers methods to measure the resistivity of semiconductor samples using
the van der Pauw method.

WARNING
To provide protection from shock hazards, the test fixture
chassis must be properly connected to a safety earth ground.
A grounding wire (18 AWC or larger) must be attached se­curely to the test fixture at a terminal designed for safety

rounding (the terminal should be marked with the symbol

-h ). The other end of the grounding wire is then attached to a

b

known safety earth ground, such as a cold water pipe, or a
grounded electrical outlet box.

3.2 SEMICONDUCTOR TEST MATRIX

Two important advantages of a matrix switching system are the ability to
connect avariety of instruments to the device or devices under test, as well

3-1

SECTION 3

Aoulications

as the ability to connect any instrument terminal to any device test node.
The following paragraphs discuss a typical semiconductor matrix test sys­tem.

3.2.1 System Configuration

Figure 3-1 shows a two Source Measure Unit test configuration. In this ex­ample, OUTPUT HI and OUTPUT LO of each Source Measure Unit are
independently switched, allowing for maximum versatility.

‘igurc 3-l. Multi Unit Connections to Mode/ 7153

This test configuration has five DUT test pins.

Source Measure Unit and test fixture connections to the matrix card are
accomplished using Model 7153-TRX cables. These cable assemblies are

3-2

SEC JION 3

Adications

terminated with 3.slot triax connectors. On each Source Measure Unit,

notice that the banana jack is used to access OUTPUT LO rather than the
triax connector. This allows OUTPUT LO to be routed to the signal path of
the matrix. On the Source Measure Unit triax connector, OUTPUT LO is
located on the inner shell which, through normal triax connections, would
put OUTPUT LO on the guard path of the matrix card.

3.2.2

The system shown in Figure 3-1 could be used to test a variety ofcharacter-

istics including ICSS, ID (OFF), Ic(ON), lnss, and Vos(OFF). To demonstrate a

practical use for the system, we will show how it can be used to generate

common source characteristic curves of a particular IFET.

In order to generate these curves, the instruments tnust be connected to the

IFET under test, as shown in Figure 3-2. The advantage of using the matrix

is, of course, that it is a simple tnatter of closing specific crosspoints. The

crosspoints that must be closed are also indicated on the diagram.

Testing Common-Source Characteristic of FETs

‘igure

3-2.

System

Source Characteristics

Configuration

for Measuring Common-

3-3

SECT/ON 3
Applications

3.3 RESISTIVITY TESTING USING MATRIX SWITCHING IN A SMU TEST SYSTEM

One example of where matrix switching is beneficial is when performing
resistivity tests on semiconductors. The following paragraphsdiscusssuch
resistivity tests using a Source Measure Unit/matrix switching system.

3.3.1 System Configuration

Figure 3-3 shows a typical system configuration for performing resistivity
tests using a Source Measure Unit. In addition to the Source Measure Unit,
which sources the test current and measures the resulting voltage drop

across the DUT, the system includes a Model 705 Scanner and a Model

7153 High Voltage Low Current Matrix Card for switching, as well as a

Model 8006 test fixture to house the device under test.

With the test configuration shown in Figure 3-3, onlyone4.terminal sam-

ple can be tested at any given time. However, additional Model 7153

cards can be daisy chained together to expand columns or rows, allowing
more than one sample to be tested by a single test procedure.

3.3.2 Test Configuration

Figure 3-4 shows a typical resistivity test configuration for a single leg
measurement of one sample. Here, the current source of the Source Meas­ure Unit sowces a current between two terminals of the sample, while the
voltage meter section of the unit measures the voltage across two of the
opposite terminals. Generally, eight such measurements are made, as
shown in Figure 3-5.

3.4

SECTION 3

Applications

3-5

SEC J/ON 3

Applications

Figure 3-5. Resistivity Measurement Conventions

3-6

SECTION 3

Aoalications

3.3.3 Resistivity Calculations

Resistivity is calculated from the voltage measurements as follows:

~~ = 1 .I 331 fntsw+V4-V,-K)

I

~” = 1 .1331 fsts(V6+Vs-Vs-V,)

I

Where oA and oB are the resistivities in &cm

tr is the sample thickness in cm
V, through Vs are the voltages measured by the Model 236
I is the current sourced by the Model 236 in amperes

fn and fe are geometrical factors based on sample symmetry

(fn = f8 = 1 for perfect symmetry)

Once ISA and 0s are known, the average resistivity, onvc, can be computed
as follows:

OAYC =

3.3.4

Figure 3-6 shows the test connections for the resistivity tests. The Model
8006 test fixture should be connected directly to the ROW jacks on the
Model 7153 High Voltage Low Current Matrix Card using an optional
Model 7153-TRX cable assembly. Connect the Model 236 to the COL
jacks of the matrix card, again using a Model 7153-TRX cable assembly.
For the OUTPUT HI, SENSE HI, and SENSE LO jacks, you can simply con­nect the triax cables to the corresponding jacks. For the OUTPUT LO con­nection, however, it will be necessary to use DNC/banana (Pomona Model

1899) and 3-14 female&w to male BNC (Pomona Model 5299) adapters.

Test Connections

OA + 00

2

3-7

SFCJION 3

Applicarions

Figure 3-6.

Jest

Connections

for

Resistivity

Jests

3.3.5 Measurement Considerations

The offset current (4 pA for the Model 7153) comes into play for very low
current measurements. The required settling time depends on the imped­ance levels involved (should be >5RC), and the path isolation can affect
the accuracy of high-impedance measurements.

NOTE

ln this application, the sense and source leads are connected to
separate points on the DUT, which will result in a potential be­tween OUTPUT HI and SENSE HI, and OUTPUT LO and
SOURCE LO. Note that the maximum voltage between the
OUTPUT and SENSE leads is limited (see specifications). Re­duce test current if necessary to keep the voltages belowspeci­fied limits.

3-O

SFCJION 3

Applications

3.3.6

Program: Resistivity Tests Using a Switching
Matrix and Source Measure Unit

The following Program demonstrates programming techniques for con­trolling a switching matrix and Source Measure Unit to perform resistivity
tests. The basic procedure for using this program is as follows:

With power off, connect the Model 23G Source Measure Unit and the

1.
Model 705 Scanner to the IEEE-48t3 bus of the computer. Also, install
the Model 7153 Card in slot 1 of the Model 705 mainframe.

2.

Connect the test fixture and the Source Measure Unit to the matrix
card using the specified triax cables (see Figure 3-6 and the discussion
above for details on test connections).
Turn on the Model 236, and allow it to warm up for at least two hours

3.
for rated accuracy. Be sure that the primary address of the Source
Measure Unit is set to 16. Also, turn on the Model 705, and make sure
that its primary address is set to 17.

4.

Turn on the computer, then boot up BASIC.

Enter lines below into the computer.

5.
Connect the sampleto betested to the appropriate socket terminals on

6.

the test fixture, and also install the necessary test fixture jumpers. Use
the general configuration shown in Figure 3-4 as a guide to test con-

nections. Close the test fixture lid after making connections.

7.

RUN the program, and follow the prompts on the screen. You will be
prompted toenter thedesired sample current value and then the sam­ple thickness, which should beentered in centimeters. When entering

the current, keep the approximate DUT resistance values in mind so

as not to create an over voltage compliance condition. Also, you must
not exceed the maximum voltage between output and sense lends of
the Source Measure Unit.
Oncetheparametersareentered, thetest will begin.TheprogramwiII

8.
program the Source Measure Unit, and then begin the tests by closing
crosspoints. A total of eight measurements will be taken and stored in
an array.

9.

Once the testing has been completed, the resistivityvalues will becal­c&ted and displayed.

3-9

SECTION 3

Applications

3.3.7

Program Description

Refer to the I’rogram listing below and the flowchart shown in Figure 3-7
for the following description.

At the start of the program, both the Source Measure Unit and the scanner
are returned to default conditions (line 20), and the reading array and com­mand string are dimensioned (line 40). Next, the Model 236, which
sources the test current and measures the sample voltage, is programmed
as follows (lines 60.120):

. Source I, DC mode

l

1 OV compliance, autorange measure

l

Remote sensing

. Measure only data format with no prefix, DC data output

l

Continuous trigger on GET

l

Line cycle integration

The Model 705 is then placed in remote (line 140), and the scanner is
placed into matrix mode (line 150). Next the operator is prompted to input
the desired test current, at which point the Source Measure Unit is pro­grammed with the current value (lines 160 and 170). The operator is then
prompted for the sample thickness (line 180), and the program waits for
the operator’s signal to begin (lines 190 and 200).

Once the operator starts the test, the Model 236 is armed and placed into
operate (line 2101, and the unit is then triggered (line 220). The program

thenentersa loop(line230)to testthesamplewith atotalofeightreadings.

As part of each loop, the Model 705 command string is read from the

DATA statements at the end of the program (line 240), and the unit is then
programmed to close the desired crosspoints (line 250). After a two-sec­ond delay for settling (line 2601, a voltage reading is requested from the
Model 236 and placed into an array (line 270). The crosspoints are then
opened by reading the next command string (line 280) and then program­ming the Model 705 accordingly (line 2901, and then the program loops
back for the tnext Imeasurement (line 300)

Finally, the program computes both IX and 0~ (lines 320 and 330), and

then it calculates and displays the average resistivity, onvc (line 360). Note

3-10

SECTION 3

Applications

that the Model 705 command strings are located in DATA statements at the
end of the program (lines 380-530).

Figure

3-7.

Program Flowchart

3-11

SECTION 3

Appkations

3-12

SECTION 3

Applications

3.4 SMU REMOTE SENSING

The Model 7153 matrix card can also be used by a single Source Measure

Unit for remote sensing. For remote sensing, the Source Measure Unit

could be connected to the matrix card as shown in Figure 3-8. OUTPUT

HI/GUARD, SENSE HI/GUARD, SENSE LO and OUTPUT LO are con­nected to separate rows for maximum switching flexibility and optimum

lowcurrentperformance. MakingtheSENSE LOconnectionalsoconnects
OUTPUT LO to the matrix card through the triax connector. However,
since it is connected to the inner shield, it is of no consequence as long as it

is not used at the test fixture. In this test configuration, OUTPUT LO is ac­cessed at the Source Measure Unit banana jack so that it can be independ­ently switched.

The test configuration in Figure 3-8 “uses” four matrix rows. Remote sens-

ing can be accomplished using three matrix rows by using OUTPUT LO at
the triax connector. In this configuration, SENSE LO and OUTPUT LO use
the same row. The disadvantage to this is the loss of some switching flexi­bility. Another option is to make OUTPUT LO a system common that is not
routed (not switched) through the card. All commons are simply
nected directly to the OUTPUT 1.0 banana jack.

con-

For high current applications where leakage current is not a consideration,
the guard paths of the matrix card can be used for 4-wire sensing as shown
in Figure 3-9. With this configuration only two matrix crosspoints are re­quired to accomplish 4.wire connections to the DUT.

3-13

SECTION 3
Applications

‘igure 3.0. Remote Sense and Guard Connections fo Model 7753

3-14

r

SECTION 3

Applications

Figure 3-9.

Remote Sensing with Guard

3-15

SECTION 3

Aodications

REFERENCES

ASTM, F76-84. “Standard Method for Measuring Hall Mobility and Hall
Coefficient in Extrinsic Semiconductor Single Crystals”. Annual Bk. ASTM
Stds., 1986: 10.05 155.

Coyle, G. et al, Switchinc! Handbook. Keithley Instruments Inc., Cleve­land, Ohio (1987).

Van der Pauw, L. J. “A Method of Measuring Specific Resistivity and Hall

Effects of Discs of Arbitrary Shape”. Philips Rec. Repts., 1958: 13 1.

3-16

SECTION 4

Service Information

4.1 INTRODUCTION

This section contains information necessary to service the Model 7153

High Voltage Low Current Matrix Card and is arranged as follows:

4.2 HandlingandCleaning Precautions: Discusses handling precautions
and methods to clean the card should it become contaminated.

4.3 Performance Verification: Covers the procedures necessary to deter­mine if the card is operating properly.

4.2 HANDLING AND CLEANING PRECAUTIONS

Because of the high-impedance circuits on the Model 7153, care should

be taken when handling or servicing the card to prevent possible contami-

nation. The following precautions should be taken when servicing the

card.

1. Handlethecardonly bytheedges. Do not touch any board surfaces or
components not associated with the repair.

2. DO not store or operate the card in an environment where dust could
settle on the circuit board. Use dry nitrogen gas to clean dust off the
board if necessary.

3. Should it become necessary to use solder on the circuit board, remove
the flux from the work areas when the repair has been completed. Use

Freon@ TMS or TE or the equivalent along with clean cotton swabs or

a clean, soft brush to remove the flux. Take care not to spread the flux

4-1

SECTION 4
Service Information

to other areas of the circuit board. Once the flux has been removed,
swab only the repaired area with methanol, then blow dry the board
with dry nitrogen gas.

4. After cleaning, the card should be placed in a 50°C low-humidity en­vironment for several hours before use.

4.3 PERFORMANCE VERIFICATION

WARNING
The following test procedures should only be performed by
qualified personnel who recognize shock hazards and are fa­miliar with the safety precautions required to avoid possible
injury.

The following paragraphs discuss performance verification procedures for
the Model 7153, including offset (leakage) current, contact potential, path

isolation, input isolation (differential and common mode), and path resis­tance.

All test procedures are to be performed with the Model 7153 installed in a
Model 705 or 706 scanner mainframe. Also, the matrix card being
checked must NOT be connected to any other card.

4.3.1 Environmental Conditions

All verification measurements except for isolation and offset current
should be made at an ambient temperature between O’C and 35°C and at a

relative humidity of less than 70%. Path isolation, input isolation and offset
current verification must be performed at an ambient temperature of 23’C

and at a relative humidity of less than 60%. lfthe matrix card has been sub­jected to temperature or humidity extremes, allow the card to environmen­tally stabilize for at least one hour before performing any tests.

4.3.2

Table 4-1 summarizes the equipment necessary to make the performance

verification tests, along with the application for each item.

4-2

Recommended Test Equipment

Service Information

Table 4-1. Recommended Test Equipment

SECT/ON 4

Manu­facturer

Keithley

Keithley 181 Nanovoltmeter
Keithley
Keithley
Keithley 7153-TRX

Keithley

Keithley 6012

Keithley 6172

AMP 201144-l

Model or

Part No. Description

617 Electrometer

196 DMM

705 or 706 Scanner mainframe

Matrix to Triax Cable Offset current and

6011 Triax to alligator clip Common mode in-

cable

Triax to UHF adapter Differential input

2-slot to 3-lug triax
adapter

Guard terminal ex­tender

Applications

Offset current and

isolation

Contact potential

Path resistance

All tests

path isolation

put isolation

isolation

Offset current, path

isolation and com-

mon mode input

isolation

Common mode in­put isolation and
contact potential

Signal terminal ex­tender (#26 AWC

copper wire)

Keithley

Keithley 237-BAN-3 ;;;x to Banana Ca-

1481 Low thermal input

cable

Contact potential

Contact potential

Path Isolation

4-3

SECTION 4
Service Information

Recommended Test Equipment (Cont.)

Coax crimping tool

Female to Female

See Table 4-2

4.3.3 Special Connection Requirements

Many of the procedures in this section require special cables and connec-

tors. The following provides the information needed to construct this

equipment. The parts used to prepare this equipment are listed in
Table 4.2.

Signal to Guard Shorting Plug

One low thermal shorting plug is required to check path resistance and

contact potential. The shorting plug (see figure 4-l 1 is built by modifying a

miniature coaxial connector pin. The short is accomplished by jamming a

small length of #24 AWG copper wire between the center conductor (sig-

nal) and the outer casing (guard). The wire is then soldered to the connec-

tor pin.

4-4

Table 4-2. Special Connection Parts

Description

Signal to Guard Short
Miniature coax connector

Coax to Banana Cable
Miniature coax connector
Coax Cable

Banana plugs (2 required)
Ferrule

Signal Terminal Extender
Miniature coax connector
Coax Cable

Ferrule

Model or
Part No.*

Amp 201 144-1

Amp 201144-l
Eelden@
DC-1 o-2

cs-747-3

Amp 201144-l
Belden@9239

cs-747-3

Service Information

SECTION 4

Application

Contact poten­tial and path

resistance

Differential
input isolation

Contact poten­tial

Figure 4-l. Signal-to-Guard Short Preparation

4-5

SFCJION 4

Service Information

Coax to Banana Cable

One coax/banana cable is required to check path resistance and differen­tial input isolation. The coax/banana cable is shown in Figure4-2. A mini-

ature coaxial female connector pin is connected to a suitable length of co­axial cable using the AMP-45638-2 crimping tool. Banana plugs are then
connected to the other end of the cable as shown in the drawing. The cable
should be kept as short as possible.

WARNING
High voltage will be present on the guard terminal when
checking input isolation. To avoid electrical shock that could
result in injury or death, make sure that the twisted braid
(guard) of the cable is adequately insulated.

Signal Terminal Extender

In order to check contact potential, a signal terminal extender is required.
Figure 4-3 shows how a signal extender can be built. A suitable length of
coaxial cable is connected to a female coaxial connector pin. A portion of

the outer shield and inner insulator of the cable is then removed to expose

a section of the center conductor (signal terminal). Make sure the outer
shield (guard) does not short out to the center conductor (signal).

4-6

Service Information

SECTION 4

Center

Conductor

(Signal)

Coax cable connected to Amp 201144-l

I

Figure 4-3. Signal Terminal Extender

4.3.4

contact using Amp 45639-2 crimping tool.

Offset Current Verification

Coax Cable

(Selden @ 9239)

Amp 201144-l

Recommended Equipment

l

Keithley 617 Electrometer

l

Keithley 7153-TRX Matrix to Triax Cable

l

Keithley 6172 2&t to 3.1~16 triax adapter

Test

Connections

Figure 4-4 shows the test connections for offset current verification. The
Model 7153 row being tested is to be connected to the Model 617 Elec­trometer input as shown. Note that the electrometer ground strap is to be
removed, and the electrometer should be operated in the unguarded
mode.

4.7

SECTION 4

Service Information

Figure 4-4. Offset Current Testinn

Procedure

NOTE
The following procedure should be performed at an ambient
temperature of 23OC and at a relative humidity of less than
60%.

1. Turn on the Model 617 power and allow it to warm up for two hours
before beginning the verification procedure.

2. After the prescribed warm up period, select the amps function and the
2pA range on the Model 617. Zero correct the instrument, and then
select autoranging.

4-8

Service

3. Connect the Model 617 to row 1 of the Model 7153, as shown in
Figure 4-4.

4. Close crosspoint RlCl (row 1, column 1) by using the Model 705 or
706 front panel controls.

5. Disable zero check on the Model 617, and allow the reading to settle.

6. Verify that the offset current reading is <l pA.

7. Enable zero check on the Model 617, and open crosspoint Rl Cl,

0. Repeat steps 4 through 7 for crosspoints Rl C2 through Rl C5. Only

one crosspoint at a time should be closed.

9. Disconnect the cable from row 1, and connect it instead to row 2.

10. Repeat steps 4 through 7 for crosspoints R2Cl through R2C5. Only
one crosspoint at a time should be closed.

11. On the Model 617, enable zero check.

12. Repeat steps 3 through 8 for rows 3 and4. Theelectrometershould be
connected to the row being tested, and only one crosspoint must be
closed at a time.

Information

4.3.5 Contact Potential Verification

Recommended Equipment

SECTION 4

l

Keithley 181 Nanovoltmeter

l

Keithley Model 1481 Low Thermal Input Cable

l

Signal to guard short (custom built; see Figure 4-l)
. Signal Terminal Extender (custom built; see Figure 4-3)
. Guard Terminal Extender (AMP-201 144-l)

Test Connections

Figure 4-5 shows the test connections for contact potential verification.

4-9

SECTION 4
Service

Information

Procedure

1. Turn on Model 181 power and allow to warm up for one hour.

2. Connect the Model 1481 cable to the Model 181.

3. Connect the jumper to column 1 at theCOL receptacle and install the
Signal Terminal Extender in row 1 of the ROW receptacle.

After the prescribed warm up period, set the Model 181 to the 2mV

4.
range, short the alligator clips ofthe cable together, and press ZERO to
null out internal offset. LeaveZERO enabled for theentire procedure.

5. Referring to Figure 4-5, connect the Model 181 to row 1 signal and
column 1 jumper of the matrix card.

6. Program the mainframe to close crosspoint Rl Cl (row 1, column 1).

4-10

Service Information

SECTION 4

Verify that the reading on the Model 181 is <2OpV.

7.

8.

From the mainframe, open crosspoint RlCl and move the jumper to

column 2.

9.

Repeat steps 6 through 8 to check the rest of the signal pathways
(crosspoints RI C2 through Rl C5)ofthe row. Only one crosspoint at a
time should be closed.

10.

Remove the Signal Terminal Extender from row 1 and install the

Guard Terminal Extender.

11.

Repeat step 6 through 9 to check the guard pathways of row 1.

12.

Repeat steps 5 through 11 for rows 2 through 4. The nanovoltmeter
should beconnectedto the row beingtestedand the jumpershould be

connected to the column being tested.

4.3.6

Path isolation Verification

These tests check the leakage resistance (isolation) between adjacent ma­trix paths. Should the card fail any of the tests, clean it using the procedures
outlined in paragraph 4.2.

Recommended Equipment

l

Keithley 617 Electrometer

. Keithley 7153.TRX Matrix to Triax Cable

l

Keithley 6172 2-slot to 3-lug triax adapter

l

Pomona 5278 female to female triax adapter

. Triax to banana cable (custom built; see paragraph 2.6.3)

Test Connections

Figure 4-6 shows the test connections for the path isolation tests. One row
being tested is to be connected to the Model 617 Electrometer input

through a Model 61 72 2.slot female to 3&g male triaxial adapter. The

other row is to be connected to the voltage source HI terminal using a spe­cially prepared triadbanana cable, the construction ofwhich is explained
in paragraph 2.6.3. Note that both the inner shield and the center conduc­tor are to be connected to the banana plug.

4-11

SECTION4

Service Information

COM and the LO terminal of the electrometer voltage source must be con­nected togetherasshown.Also,theground IinkbehveenCOMandchassis
must be removed, and the Model 617 guard must be turned off for current

measurements,

Figure 4-6. Path Isolation

4-12

,153

Equivalent Circuit

Testing

Service Information

SECTION 4

WARNING

Hazardous voltage from the electrometer voltage source will
be used in the following steps. Take care not to contact live
circuits, which could cause personal injury or death.

NOTE
The following procedure must be performed at an ambient
temperature of 23’C and at a relative humidity of less than
60%.

1. Turn on theModel 617 and allow it to warm up for two hours for rated
accuracy.

2. After the prescribed warm up period, select the Model 617 amps func­tion, and enable zero check. Select the 20pA range, and zero correct
the instrument.

3. Connect theModel 617 to rows 1 and 2 of the matrix card, as shown in
Figure 4-6.

4. Program the Model 617 voltage source for a value of i-1 OOV, but do
not turn on the voltage source output.

5. Close crosspoints RlCl (row 1, column 1) and R2C2 (row 2, column

2) from the mainframe.

6. With the Model 617 in amps, enable suppress after the reading has

settled.

7. Turn on the Model 617 voltage

ohms function on the electrometer.

8. After the reading has settled, verify that the resistance is >lOl-!J

(I O’Q,.

9. Turn off the voltage source, and enable zero check. Disable suppress,
and select the amps function on the electrometer.

10. From the front panel ofthe mainframe, press the RESET button to open
all crosspoints.

11. Using Table 4-3 as a guide, repeat steps 5 through 10 for the
crosspoint pairs listed starting with Test No. 2. Note that Model 617 is
connected to rows 2 and 3 for tests 5 through 8, and connected to
rows 3 and 4 for tests 9 through 12. Before moving the test connec-

tions, make sure the voltage source is off.

source

output, and enable the V/l

4-13

SECTION 4

service Information

Table 4-3. Path isolation Testing

Test

NO.

Electrometer V-Source

Input output

617 -ion

Crosspoint Pairs

Closed

1 Row 1 Row 2

2
3
4

5

Row 2 Row 3

6
7
8

9

10
11

Row 3 Row 4

12

4.3.7

These tests check the leakage resistance (isolation) between signal and
guard of matrix pathways. Should the card fail any of the tests, clean it us­ing the procedures outlined in paragraph 4.2.

Differential Isolation Verification

RlCl R2C2
RlC2 R2C3
RlC3 R2C4

RlC4 R2C5

R2Cl
R2C2 R3C3
R2C3
R2C4 R3C5

R3Cl R4C2
R3C2 R4C3

R3C3 R4C4
R3C4 R4C5

R3C2

R3C4

Recommended Equipment

. Keithley 617 Electrometer

Keithley 6012 Triax to UHF adapter

.

Pomona 5278 female to female triax adapter

l

Coax to banana cable (custom built; see Figure 4-2)

l

4-14

Service Information

SECTION 4

Test Connections

Figure 4-7 shows thetest connections for the path isolation tests. The cable
is connected to the row beingtested. One banana plug (signal) of the cable

is to be connected to the Model 617 Electrometer input through a Model

6012 triax to UHF adapter. The plug mates to the center conductor of the

UHF connector. The other banana plug (guard) connects to the electrome-

ter voltage source.

Figure 4-7.

Differential Input Isolation Testing

7153

Equivalent

Circuit

4-15

SECTION 4

Service information

COM and the LO terminal ofthe electrometer voltage source must be con-

nected togetherasshown. Also, theground link between COM andchassis
must be removed, and the Model 617 guard must be turned off for current
measurements.

Procedure

WARNING WARNING
Hazardous voltage from the electrometer voltage source will Hazardous voltage from the electrometer voltage source will
be used in the following steps. Take care not to contact live be used in the following steps. Take care not to contact live
circuits, which could cause personal injury or death. circuits, which could cause personal injury or death.

NOTE
The following procedure must be performed at an ambient
temperature of 23’C and at a relative humidity of less than

60%.

1. Turn on theModel 617 and allow ittowarm upfortwo hours for rated

XCllLXy.

2. After theprescribedwarm up period, selecttheModel617 ampsfunc­tion, and enable zero check. Select the 2nA range, and zero correct
the instrument.

3. Connect the Model 617 to row 1 of the matrix card, as shown in

Figure 4-7.

4. Program the Model 617 voltage source for a value of +l OOV, but do
not turn on the voltage source output.

5. Close crosspoint Rl Cl (row 1, column 1) from the mainframe.

6. With the Model 617 in amps, enable suppress after the reading has
settled.

7. Turn on the Model 617 voltage source output, and enable the V/l
ohms function on the electrometer.

l3. After the reading has settled, verify that the resistance is >l OTa

(low).

9. Turn off the voltage source, and enable zero check. Disable suppress,
and select the amps function on the electrometer.

10. From the front panel ofthe mainframe, press the RESET button to open
the crosspoint.

11. Connect the Model 617 to row 2 of the matrix card and repeat steps 5
through 10 for crosspoint,R2C2.

4-16

Service information

SECTION 4

12. Connect the Model 617 to row 3 of the matrix card and repeat steps 5

through

10 for crosspoint R3C3.

13. Connect the Model 617 to row 4 of the matrix card and repeat steps 5
through 10 for crosspoint R4C4.

14. With the electrometer still connected to row 4, repeat steps 5 through

10 for crosspoint R4C5.

4.3.8 Common Mode Isolation Verification

These tests check the leakage resistance (isolation) between signal/guard
and chassis ground of matrix pathways. Should the card fail any of the
tests, clean it using the procedures outlined in paragraph 4.2.

Recommended Equipment

l

Keithley 617 Electrometer

. Keithley 6011 Triax to alligator clip cable

l

Signal to guard short (custom built; see Figure 4.1)

Test Connections

Figure 4-8 shows the test connections for these tests. The Model 6011 ca­ble is connected to the electrometer input as shown. The alligator clip on

the black test lead of the cable is connected to the screw housing of the

receptacle (chassis ground). The signal to guard short is installed in the row
to be tested. The alligator clip on the red test lead is then connected to the
short (signal/guard).

The Model 617 guard must be turned off for current measurements.

4-17

SECTION 4
Service

Information

Equivalent Circuit

%mre 4-8.

Procedure

The following procedure must be performed at an ambient
temperature of 23°C and at a relative humidity of less than
60%.

Turn on the Model 617 and allow it to warm up for two hours for rated

I.

accuracy.

4-18

Common ModeInput

Isolation Testina

NOTE

Service Information

2. Afterthe prescribedwarm up period, selectthe Model 617 ohmsfunc­tion, enable zero check, and select the 1 OGn range.

3. Connect the Model 617 to row 1 and chassis ground of the matrix
card, as shown in Figure 4-8.

4. Close crosspoint Rl Cl (row 1, column I) from the mainframe.

5. On the Model 617, release zero check. After the reading has settled,
verify that the resistance is >I GI;1 (lOYQ2).

6. On the Model 617, enable zero check.

7. From the front panel ofthe mainframe, press the RESET button to open
the crosspolnt.

8. Connect the short and red test lead from the Model 617 to row 2 of the
matrix card and repeat steps 4 through 7 for crosspoint RZC2.

9. Connect the short and red test lead from the Model 617 to row 3 and
repeat steps 4 through 7 for crosspoint R3C3.

10. Connect the short and red test lead from the electrometer to row 4 and
repeat steps 4 through 7 for crosspoint R4C4.

11. With theelectrometer still connected to row4, repeat steps4 through
7 for crosspoint R4C5.

4.3.9 Path Resistance Verification

SECTION 4

The following paragraphsdiscuss theequipment, connections, and proce­dure to check path resistance. Should a particular pathway fail the resis­tance test, the relay (or relays) for that particular crosspoint is probably de­fective. See the schematic diagram at the end of Section 5 to determine
which relay is defective.

Recommended Equipment

l

Keithley 196 DMM

l

Banana to clip-on test lead

l

Coax to banana cable (custom built; see Figure 4-2)

l

Signal to guard short (custom built; see Figure 4-l)

4-19

SECTION 4
Service Information

Connections

Figure 4-9 shows the connections for the path resistance tests. A specially
prepared shorting plug is used to connect signal to guard, and is installed at

the column being tested. The Model 196 low terminal is connected to the

shorted column usingthe banana/clip-on test lead. This test lead clipsonto

the installed shorting plug. The high terminal of the DMM connects to the

row being tested using the specially constructed coax/banana cable.

Procedure

Turn on the Model 196 DMM and allow it to warm up for at least one

1.
hour before beginning the test.
Using Figure 4-9 as a guide, connect the cable (signal) and test lead to

2.

the DMM, but do not make connections to the matrix card.
Temporarily clip the test lead to the inner conductor of the coax con-

3.
nector pin of the cable. This will short the DMM input.
Select the ohms function, 3OOn range, and 5-l/2 digit resolution on

4.
the Model 196.
After the reading settles, enable zero on the Model 196 DMM. Leave

5.
zero enabled for the following tests.

6. Connect the cable and test lead to the matrix card as shown in

Figure 4-9.

7. From the mainframe, close crosspoint RlCl (row 1, column 1) and

allow the reading to settle. Verify that the resistance reading is < 2n.
On the mainframe, press the RESET button to open the crosspoint.

8.

Repeat steps 7 and 8 for columns 2,3 and 4. In each case the short and

9.
test lead must be connected to the column under test, and the

crosspoint must be closed.

IO. Repeat steps 7 through 9 for rows 2, 3 and 4. In each case, the elec-

trometer is connected to the row under test. The crosspoint to close is
the one corresponding to the row and column connections at that
time. In all cases, the measured resistance should be < 2Q.

11. Disconnect the coax/banana cable from the matrix card and the
DMM. Also, disconnect the clip-on test lead from the matrix card.

12. On the Model 196, disable zero.

13. Connect the guard banana plug of the cable to the HI terminal of the
DMM. Do not make any connections to the matrix card.

Temporarily clip the test lead on to the outer shell of the coax connec-

14.

tor pin of the cable. This will short the DMM input.

15. After the reading settles, enable zero on the Mddel 196. Leave zero

enabled for the remaining tests.

4-20

Service Information

SECTION 4

16. Install the signal to guard shorting plug at column

17. Connect the cable and test lead to the matrix card as shown in
Figure 4-9. Note however, that guard (not signal as shown in the
drawing) is to be connected to DMM HI.

18. Repeat steps 7 through 10 to test guard pathway resistance.

1.

‘&we 4-9. Path Resistance Tcstinx

Equivalent

Circuit

4-21

SECTION 5

Replaceable Parts

5.1 INTRODUCTION

This section contains a list of replaceable electrical and mechanical parts
for the Model 7153, as well as a component layout drawing and schematic
diagram of the card.

5.2 PARTS LIST

Electrical parts are listed in order of the circuit designation. A miscellane­ous parts list table is located at the end of this section.

5.3 ORDERING INFORMATION

To place a parts order, or to obtain information concerning replacement

parts, contact your Keithley representative or the factory (see the inside

front cover for addresses). When ordering parts, be sure to include the fol-

lowing information:

1. Card model number

2. Card serial number

3. Part description

4. Circuit description, if applicable

5. Keithley part number

5.4 FACTORY SERVICE

If the card is to be returned to Keithley Instruments for repair, perform the

following:

5-l

SECTION 5

Replaceable Parts

1, Complete the service form at the back of this manual and include it

with the card.

2. Carefully pack the card in the original packing carton.

3. Write ATTENTION REPAIR DEPARTMENT on the shipping label.

5.5 COMPONENT LAYOUT AND SCHEMATIC DIAGRAM

A component layout of the driver board is contained in drawing number

7153-160, while drawing number 7153-166 contains a schematic dia­gram. A component layout of the delay board is contained in drawing
number7153-100,whiledrawingnumber7153-106containsaschematic
diagram.

5-2