Recommended Test Equipment; Test Equipment Connections; Calculating Test Limits; Example Limit Calculation - Keithley 6220 Reference Manual

16-4 Performance Verification

Recommended test equipment

Table 16-1
ical suitable models. Ideally, test equipment uncertainty should be at least four times
better than equivalent Model 6220 or 6221 specifications. However, the equipment
listed for the 2nA and 20nA ranges does not quite meet that requirement.
Table 16-1
Recommended test equipment
Description
Digital Multimeter
1
Picoammeter
2
Frequency Counter
2
Test Resistor
1. Equipment used to test output current and compliance accuracy of both 6220 and 6221.
2. Equipment used to test wave functions of 6221 only.

Test equipment connections

For the sake of clarity, only actual signal lines are shown in test equipment con-
nection drawings in this section. To ensure measurement integrity, be sure to use
appropriate triax cables or (where appropriate) coax cables for all connections.

Calculating test limits

The test limits stated in this section have been calculated using only the
Model 622x one-year accuracy specifications, and they do not include test equip-
ment uncertainty. If a particular measurement falls slightly outside the allowable
range, recalculate the new limits based on both Model 622x specifications and
pertinent calibration equipment specifications.

Example limit calculation

The following is an example of how test limits have been calculated. Assume you
are testing the 20mA range using a 20mA output current. Using ±(0.05% + 10μA)
accuracy, the calculated limits are:
Output current limits = 20mA ±[20mA(0.05%) + 10μA]
Output current limits = 19.980 to 20.020mA
Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176 - TestEquipmentDepot.com
summarizes recommended test equipment specifications as well as typ-
Key specifications
Measure 200nA to 100mA DC, ±100ppm
Measure 10V and 100V DC, ±100ppm
Measure 100mA AC @ 1kHz and 100kHz
Measure 2nA and 20nA DC, ±2000ppm
Measure 1kHz sine wave within ±25ppm
50Ω, 1/2W composition
Return to
Model 6220/6221 Reference Manual
1
Agilent 3458A
1
2
Keithley 6487
Any suitable
Any suitable
Section 16 topics
Manufacturer/model