34925A 40/80-Channel Optically-Isolated Fet Multiplexer; Two-Wire Mode; Four-Wire Mode - Agilent Technologies 34921A User Manual

34925A 40/80-Channel Optically-Isolated FET Multiplexer

34925A 40/80-Channel Optically-Isolated FET Multiplexer
The 34925A 40/80- Channel Optically- Isolated FET Multiplexer (40/80- Ch
FET MUX) module is a high- speed and high- density FET MUX for high
throughput production test. This module is divided into two equal banks
of non- latching FET switches. This module also contains four armature
Analog Bus relays. Through ABus1 and ABus2 you can connect any of the
channels to the internal DMM for voltage or resistance measurements.
When the power is off, all channel and Analog Bus
relays open.
Using program commands or the mainframe front panel, you can control
each of the FET channel switches individually, and configure this module
for differential (2- wire or 4- wire) or single- ended (1- wire) mode.
Refer to the simplified schematics on
If you are using an Agilent 34925T- 00x terminal block to connect your
DUT to this module, be sure to use the terminal block that corresponds to
your module configuration mode (Refer to the terminal block drawings on
page 38
34925T-001 (Option 001)
34925T-002 (Option 002)
You can confirm the mode in which your module is configured by using
the SYSTem:CTYPe? <slot number> program command. This command
returns the identity of the plug- in module in the specified slot.

Two-Wire Mode

• two independent 20- channel 2- wire MUXes. This configuration requires
• one 40- channel, 2- wire MUX. You must use external wiring or connect

Four-Wire Mode

• You may configure the 34925A as a single 20- channel 4- wire MUX. This
34
and page 41):
Terminal block for differential (two- or four-wire) mode
Terminal block for single-ended (1-wire) mode
Whenever you change from 2- or 4-wire mode to 1-wire mode, or
N O T E
the reverse, you must cycle power on the 34980A for the
configuration to take effect.
neither using external wiring nor connecting through the internal
Analog Bus relays.
through the Analog Bus relays to for this configuration.
configuration requires using neither external wiring nor connecting
through the internal Analog Buses. For 4- wire resistance measurements,
the instrument automatically pairs channel n on Bank 1 (source) with
channel n+20 on Bank 2 (sense) to provide these connections.
Four- wire controls occur only when doing 4- wire measurement
operations through the internal DMM, such as MEASure:FRESistance?
or scanning a channel previously configured as 4- wire.
Agilent 34921A-34925A Low Frequency Multiplexer Modules User's Guide
page 36 and page 39.