Understanding high-capacitance mode
The source-measure unit (SMU) in the 2600B drives 10 nF of capacitance in normal operation.
Typically, an internal capacitor across the current measuring element provides phase lead to
compensate for the phase lag caused by the load capacitance on the output. This internal
capacitance across the range resistance limits the speed for a specific measurement range.
The SMU in the 2600B implements frequency compensation to achieve the highest throughput
possible for a 10 nF or less load. In addition, you must consider the settling time, voltage range,
measure delay, the quality of the capacitor, the current measure range resistor, and the load resistor.
In normal operation, the SMU in the 2600B can drive capacitive loads as large as 10 nF. In
high-capacitance mode, the SMU can drive a maximum of 50 μF of capacitance.
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 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.
Understanding source settling times
Each 2600B source-measure unit (SMU) can drive up to 50 μF of a capacitance in high-capacitance
mode. To accomplish this, the speed of the 2600B SMU is reduced. Source settling times increase
when high-capacitance mode is enabled. The following tables compare the source settling times in
normal and high-capacitance modes.
To Next Page
Loading...
Need help?
General
