Keithley 2657A-PM-200 User Manual page 8

Model 2657A-PM-200 Protection Module
Connections using a Model 4200-SCS SMU (with Model 4200-PA)
If ordered, a Model 4200-PA remote preamplifier (preamp) for a source-measure unit (SMU) is installed at the
factory when the Model 4200-SCS is ordered.
Required accessories to connect one Model 4200-SMU or 4210-SMU (with the Model 4200-PA):
•
Two or three Model 4200-TRX cables
•
Two or three high-voltage (HV) triaxial cables (Model CA-553 or CA-554)
Connection summary
Use the connection drawing below to connect a Model 4200-PA preamp and the GNDU (ground unit) to the Model
2657A-PM-200. Make sure to use the IN connectors of the Model 2657A-PM-200 for connection to the Model 4200-
SCS and use the OUT connectors for connection to the device under test (DUT).
The drawing shows connections for 4-wire sensing. For 2-wire applications, the SH (sense HI) connectors of the
Model 2657A-PM-200 are not used.
When using multiple SMUs that are installed in the Model 4200-SCS, each SMU needs its own
protection module. To achieve adequate voltage protection, connect the GNDU Sense terminal to the
LO,SL (LO and sense LO) connector of each protection module using triax tees (such as the Keithley
Model 237-TRX-T) and additional triaxial cables (Model 4200-TRX).
Connecting the Model 4200-SMU or 4210-SMU to the Model 2657A-PM-200 connects the LO
terminal of the SMU to protective earth (safety ground).
Do not convert triaxial cables to BNC cables. Using BNC cables removes protection from the Model
4200-SCS SMU and may result in damage to the SMU. You must use triaxial cables to connect to the
lower-voltage SMU.
8 PA-1055 Rev. A / February 2012