2600AS-901-01 Rev. B / September 2008 Return to Section Topics 22-15
Series 2600A System SourceMeter® Instruments Reference Manual Section 22: Performance Verification
Model 2635A/2636A current measurement accuracy 100pA to 100nA 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 1GΩ resistor and comparing the Model 2636A/2636A measured results against
the standard resistance and voltage derived current.
1. Characterize the appropriate +/- V source values with the DMM according to Table 22-9.
2. Characterize the desired Model 2635A/2636A 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 2635A/2636A reported current measurement.
e. Verify output current accuracy for each of the currents for the 100pA to 100nA ranges
listed in
Table 22-12 (Model 2635A/2636A).
Table 22-9
Model 2635A/2636A Characterization of Voltage Source settings
Low Current Range Voltage Source Compliance
100 pA +/- 100.00 mV 1.5 A
1 nA +/- 1.0000 V 1.5 A
10 nA +/- 10.000 V 1.5 A
100 nA +/- 100.00 V 100 mA
Table 22-10
Model 2601A/2602A current measurement accuracy limits
Model 2601A/2602A
source and
measure range
1
Source
current
2
Model 2601A/2602A current reading
limits
(1 year, 18°C–28°C)
100nA
1µA
10µA
100µA
1mA
10mA
100mA
1A
3A
90.000nA
0.9000µA
9.0000µA
90.000µA
0.9000mA
9.0000mA
90.000mA
0.90000A
2.4000A
89.855 to 90.145nA
0.899475 to 0.900525µA
8.99625 to 9.00375µA
89.957 to 90.043µA
0.89962 to 0.90038mA
8.9957 to 9.0043mA
89.962 to 90.038mA
0.89823 to 0.90177A
2.3953 to 2.4047A
1. Measure range coupled to source range when simultaneously sourcing and measuring
current.
2. As measured by precision digital multimeter. Use closest possible value, and modify reading
limits accordingly if necessary.