Keithley 237

KE1TH LEY
1
NSTRUMENTS
Model
236
Source
Measure
Unit
and
Model
237
High
Voltage
Source
Measure
Unit
Service
Manual
Publication
Date: October 1991
Document Number:
236-902-01
Rev.
D
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Contains
Servicing
Information
for
the
Model
236/237

Keithley 237 Specifications

General

Output Power	200 W
Voltage Resolution	1 μV
Current Resolution	10 fA
Type	Source Measure Unit
Interface	GPIB, RS-232
Accuracy	0.02%
Compliance Voltage	±1100V

Summary

WARRANTY

LIMITATION OF WARRANTY

SAFETY PRECAUTIONS

General Safety Precautions

Outlines essential safety guidelines for operating the Model 236/237 Source Measure Units.

SICHERHEITSHINWEISE

PRECAUZIONI DI SICUREZZA

MEDIDAS DE SEGURIDAD

SPECIFICATIONS

SOURCE-MEASURE UNIT

Basic function and modes of the source-measure unit.

CURRENT

Detailed specifications for current sourcing and measurement capabilities.

VOLTAGE

Detailed specifications for voltage sourcing and measurement capabilities.

SECTION 1 Performance Verification

Table 1-1. Required Test Equipment

Figure 1-1. Setup for Equipment Characterization

Illustrates the setup for equipment characterization.

Table 1-3. Model 263 I-Source Characteristics

1.5.2 Common Mode Verification

Figure 1-2. Setup for Common Mode Verification

1.5.3 Voltage Source Verification

Outlines procedures to verify the voltage source functionality.

1.5.4 Voltage Measure Verification

Details procedures for verifying voltage measurement accuracy.

Figure 1-3. Setup for Voltage Source Ranges Verification

Diagram showing setup for voltage source range verification.

Table 1-5. Voltage Measure Verification

Table of voltage measure verification data and allowable readings.

Figure 1-5. Setup for Remote Sense Verification

Table 1-6. Allowable Reading Calculations for Low Current Measure Verification (1 A to 10 mA)

Table 1-7. Low Current Measure Verification (inA to 10 mA)

1.5.7 Low Current (1 nA to 1 OmA) Source Ranges Verification

Verifies low current source ranges from 1nA to 10mA.

Figure 1-7. Setup for Low Current Source Ranges Verification (inA to 10 mA)

Setup diagram for low current source range verification.

Table 1-8. Allowable Reading Calculations for Low Current Source Verification (1 A to 10 mA)

1.5.8 100 mA Measure Range Verification

Procedure to verify the 100mA measure range.

Figure 1-8. Setup for lOOmA Measure Range Verification

Diagram illustrating the setup for 100mA measure range verification.

1.5.9 100 mA Source Range Verification

Procedure to verify the 100mA source range.

Figure 1-9. Setup for 100 mA Source Range Verification

Diagram illustrating the setup for 100mA source range verification.

1.5 VERIFICATIONS PROCEDURES

Outlines the step-by-step procedures for verifying instrument performance.

1.5.1 Equipment Characterization

Describes the procedure for characterizing equipment used in verification.

Table 1-4. Voltage Source Verification

Table with voltage source verification data and limits.

1.5.5 Remote Sense Verification

1.5.6 Low Current (1 nA to 10 mA) Measure Ranges Verification

Verifies low current measure ranges from 1nA to 10mA.

Figure 1-6. Setup for Low Current Measure Ranges Verification (inA to 10 mA)

Setup diagram for low current measure range verification.

1.4 RECOMMENDED TEST EQUIPMENT

SECTION 2 Calibration

Table 2-1. Required Test Equipment

Figure 2-2. Setup for Equipment Characterization

Illustrates the setup for equipment characterization.

Table 2-3. Model 263 I-Source Characterization

2.6.2 Voltage Calibration

Details the procedure for calibrating voltage source and measure ranges.

Figure 2-3. Setup for Volts Calibration

Illustrates the setup for voltage calibration.

2.6.3 lOOmA Range Calibration

Procedure for calibrating the 100mA source and measure range.

Figure 2-4. Setup for 100 mA Range Calibration

Illustrates the setup for 100mA range calibration.

2.6.4 Low Current Ranges Calibration (1 nA - 10 mA)

Calibrates low current ranges from 1nA to 10mA.

Figure 2-5. Current Ranges Calibration (inA to 10 mA)

Diagram for current ranges calibration (inA to 10mA).

2.7 CALIBRATION ERRORS

2.2 RECOMMENDED CALIBRATION EQUIPMENT

2.6.1 Equipment Characterization

Describes characterizing equipment for calibration accuracy.

2.6 CALIBRATION PROCEDURES

Provides step-by-step procedures for instrument calibration.

SECTION 3 Maintenance

3.3 FAN FILTER CLEANING

3.7 SPECIAL HANDLING OF STATIC SENSITIVE DEVICES

3.8.3 Power Supply Checks

Details checks for the instrument's power supply circuits.

Table 3-9. Digital Circuitry Checks

Table 3-10. Display Circuitry Checks

3.2 LINE FUSE REPLACEMENT

3.4 BATTERY REPLACEMENT

3.6 DISASSEMBLY INSTRUCTIONS

Step-by-step instructions for disassembling the instrument.

3.8 TROUBLESHOOTING

Provides guidance for diagnosing and resolving instrument issues.

3.8.6 Digital and Display Checks

3.8.1 Recommended Test Equipment

3.8.2 Diagnostics

SECTION 4 Principles of Operation

4.2 ANALOG CIRCUITRY

Explains the analog circuitry, including error amplifier and bootstrap amplifier.

4.2.2 Output Stage

4.2.3 VI Feedback

4.2.4 Resonant Converter (Model 237)

4.4 DIGITAL CIRCUITRY

4.4.2 SourceMeasure Controller

4.5 POWER SUPPLY

4.2.1 VI Control and Readback

Describes the V/I control and readback circuitry.

4.3 AD CONVERTER

4.4.1 IO Controller

SECTION 5 Replaceable Parts

5.5 SCHEMATIC DIAGRAMS AND COMPONENT LOCATION DRAWINGS