I-Source Sink Operating Boundaries - Tektronix KEITHLEY System SourceMeter 2636B Reference Manual

Series 2600B System SourceMeter® Instrument Reference Manual Section 7: Theory of operation

I-source sink operating boundaries

The quadrant within which the Series 2600B operates depends on the device-under-test (DUT)
connected to the Series 2600B output. The following example illustrates this operation by using the
Series 2600B configured to provide a constant current to discharge a 12 V power source (a battery).
When using the I-Source as a sink, always set the voltage compliance limit to levels that are
higher than the external voltage level. Using the Model 2601B/2602B/2604B to sink more than
3 A can damage the instrument and invalidate your warranty. Using the Model
2611B/2612B/2614B/2634B/2635B/2636B to sink more than 1.5 A can damage the instrument
and invalidate your warranty.
Figure 96: Sourcing current sink operation example
The voltage compliance limit applies both to positive and negative voltages. For example, if you set
the voltage compliance limit to 15 V, the voltage limit applies to ±15 V.
For this example, the Series 2600B is programmed to source −50 mA (the constant current) and to
limit voltage to 15 V. When the SMU turns on, it begins sinking current as determined by the
programmed I-source level (-50 mA), causing a decrease in the battery voltage. If the battery were
ideal and could be charged negatively, its voltage would then continue to decrease until it is
negatively charged at −15 V (shown by the green arrow in the following figure), at which point the
SMU would be in voltage compliance.
Make sure to take into account that reversing the polarity may destroy some power sources. To
prevent a negative charge, monitor the SMU's measurement of the battery voltage and stop the
discharge before the Series 2600B starts to operate in quadrant III (negative voltage). You can stop
the discharge by changing the programmed current source level or by disconnecting the SMU from
the device.
2600BS-901-01 Rev. E / January 2019 7-17