Keithley 2657A-PM-200 User Manual page 6

Model 2657A-PM-200 Protection Module
Connections using a Model 2635A or 2636A SMU
Required accessories:
•
Two or three standard triaxial cables (either Model 7078-TRX or 4200-TRX) per source-measure unit (SMU)
channel
•
Two or three high-voltage (HV) triaxial cables (Model CA-553 or CA-554) per SMU channel
Connection summary
Use the connection drawing below to connect source-measure unit (SMU) channels of the Model 2635A or 2636A
to the Model 2657A-PM-200. For each channel, make sure to use the IN connectors of the Model 2657A-PM-200
for connection to the Model 2635A or 2636A 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.
Do not convert triaxial cables to BNC cables. Using BNC cables removes protection from the Model
2635A or 2636A and may result in damage to the SMU. You must use triaxial cables to connect to the
lower-voltage SMU.
When using the 2657A-PM-200, HI and SH (sense HI) should be connected together at the device
under test. A potential difference between the two circuits in excess of 100 mV may result in
compromised measurements.
Large potential differences can be created when there is significant lead resistance and current
flowing in the HI lead. To minimize lead resistance, minimize the distance between the Model 2657A-
PM-200 and the device under test.
6 PA-1055 Rev. A / February 2012