Keithley 2601B Reference Manual page 201

Section 3: Functions and features Series 2600B System SourceMeter® Instrument Reference Manual
When high-capacitance mode is enabled, a minimum load capacitance of 100 nF is recommended.
In absence of this minimum load capacitance, overshoot and ringing may occur.
Highest throughput is achieved by using normal operation. In high-capacitance mode, the speed of
the Series 2600B SMU is reduced to compensate for the larger load capacitance. Stability is achieved
by inserting an internal capacitance across the current measuring element of the SMU. This internal
capacitor limits the speed for the source and measurement ranges. Therefore, when optimizing the
speed of your test configuration in high-capacitance mode, you must consider the settling time,
voltage, and current ranges, measure delay, quality of the load capacitor, and load resistance.
3-66 2600BS-901-01 Rev. B / May 2013