Keithley 2601B Reference Manual page 756

Appendix B: Calibration
Model 2634B/2635B/2636B current measurement accuracy 100 pA to 100 nA
ranges
A suitably guarded and characterized 1 GΩ resistance standard, such as the Keithley
Instruments Model 2600-STD-RES, is necessary for the following measurements. Step-by-step
procedures and connection diagrams for verifying the current measurement accuracy for the low
current ranges are included with the Model 2600-STD-RES. The general process entails forcing a
characterized voltage across the 1 GΩ resistor and comparing the Model 2634B/2635B/2636B
measured results against the standard resistance and voltage derived current.
1. Characterize the appropriate ±V source values with the DMM according to the following table.
Model 2634B/2635B/2636B Characterization of Voltage Source settings
Low Current Range
100 pA*
1 nA
10 nA
100 nA
* Not available on the Model 2634B.
2. Characterize the desired Model 2634B/2635B/2636B current ranges.
a. Connect guarded resistance standard.
b. Source the appropriate voltage for +/- full-scale reading.
c. Wait 30 seconds for stable measurement.
d. Capture the Model 2634B/2635B/2636B reported current measurement.
e. Verify output current accuracy for each of the currents for the 100 pA to 100 nA ranges listed in
the following table.
Model 2634B/2635B/2636B current measurement accuracy limits (100 pA to 100 nA)
Measure range
1
100 pA
1 nA
10 nA
100 nA
1. Not available on the Model 2634B.
2. As measured by precision digital multimeter. Use closest possible value, and modify reading limits
accordingly if necessary. See
B-14
Series 2600B System SourceMeter® Instrument Reference Manual
Voltage Source
±90.000 mV
±0.90000 V
±9.0000 V
±90.000 V
2
Source current
90.000 pA
0.90000 nA
9.0000 nA
90.000 nA
Measurement limit calculations
Compliance
1.5 A
1.5 A
1.5 A
100 mA
Current reading limits (1 year,
18 °C to 28 °C)
89.785 pA to 90.215 pA
0.89841 nA to 0.90159 nA
8.9835 nA to 9.0165 nA
89.906 nA to 90.094 nA
(on page B-4).
2600BS-901-01 Rev. B / May 2013