User Manual

Model 3760
10-Channel High Current Multiplexer Card User's Manual Section 5:
Typical applications
3760-900-01 Rev. A / July 2017 5-3
Four-wire application
Connecting multiple DUTs to one instrument using either a Kelvin technique or external sense as with
a Source Measure Unit (SMU), requires two cards operating in four-pole mode. This is shown in the
next figure.
The Guard and Shield are connected to the card end only and not to the device under test. Also, on
the source-measure instrument, the Guard connection is not always made. It may not be required at
high current levels, such as when circuit leakage is lower than high current accuracy requirements.
Figure 11: Source with external sense or Kelvin measurement
HI and Sense HI (S+) are switched through one card. Since this is a driven guard, it is connected only
to the guard of the instrument and not terminated at the DUT.
LO and Sense LO (S-) are switched through the second card. Note that Card #2 is connected to the
cable shielding to provide shielding for these lines. The shield on the cabling should cover as much of
the signal lines as possible, and should be terminated only at the instrument. Shields are typically at
circuit low or earth ground.
This configuration combines sense and Kelvin configurations so that guard on the card is driven for
the High leads and provides a shield for the Low leads.