Section 3: Working with devices and instruments
Model 8010 High Power Device Test Fixture User's Manual
3-28
8010-900-01 Rev. C / March 2017
Figure 38: Model 4210-CVU impedance measurement system
Discharge bias tee and system capacitance
The capacitance of the bias tees in the Models CVU-200-KIT and CVU-3K-KIT can hold charge.
Devices with sufficient capacitance can also hold charge. A shock hazard exists if a proper discharge
is not performed and you open the Model 8010 cover or touch one of the instruments or device
terminals. Never assume that the safety interlock discharges the system.
Be sure to use the Model 2657 SMU to discharge the capacitance properly after each test and before
opening the Model 8010 cover. Use the discharge probe by touching the banana jack and BNC
cables and connectors inside of the fixture. The Model 2657 SMU is programmed in ACS Basic to
safely discharge the bias tee and device capacitance after completing a High Voltage C-V test. Note
that an operator error, a power outage, or an unforeseen event can leave a dangerous charge in the
system. Therefore, the Model CVU-3K-KIT includes the 8020-DP High Voltage Discharge Probe. Use
this discharge probe to manually discharge the bias tee capacitance and system capacitance within
the 8010.
Discharge system capacitance with the Model 2657
Before removing the cover of the Model 8010 and changing cable connections, a best practice is to
discharge the system capacitance with the SMU output on. Configure the SMU to force 0 V and
measure current with a current limit of at least 1 mA. A current measurement of approximately 0 mA
indicates a proper discharge. Keithley's ACS Basic software executes this discharge procedure after
completing a high voltage C-V test. ACS Basic will set the Model 2657 output to 0 V with a current
limit of 1 mA and hold for 1 second prior to turning off the output.
Figure 39: Model 2657 output to 0 volts