Datasheet
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34980A multiplexer switch modules
The 34980A multiplexer modules can be used to connect one of many different points to a single point.
You can connect to an external instrument or scan multiple analog signals to the internal DMM.
Choose from the following features:
• 1-wire, 2-wire, or 4-wire configurations
• High voltage—up to 300 V, 1 A
• High density—70 2-wire or 80 1-wire channels
• Scan up to 1000ch/sec with the 34925A
• Bandwidths up to 45 MHz
• Temperature measurements with built-in thermocouple reference junction (34921T)
• AC or DC current measurements without external shunts
• Flexible connections via standard 50- or 78- pin Dsub cables or detachable terminal blocks
Voltage
AC/DC
Current
AC/DC
Freq/
Period
Ω 2-
Wire
Ω 4-
Wire
Thermo-
couple
RTD
2-Wire
RTD
4-Wire
Thermistor
34921A Armature Multiplexer
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
34922A Armature Multiplexer
Yes
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
34923A Reed Multiplexer (2-wire)
Yes
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
34923A Reed Multiplexer (1-wire)
Yes
No
Yes
Yes
No
Yes
Yes
No
Yes
34924A Reed Multiplexer
Yes
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
34925A FET Multiplexer (2-wire)
Yes
No
Yes
Yes
Yes
Yes
No
Yes
No
34925A FET Multiplexer (1-wire)
Yes
No
Yes
Yes
No
Yes
No
No
No
NOTE: See User’s Guide for additional information.
Multiple multiplexers can connect to the built-in analog buses, allowing you to scan up to 560 2-wire
channels or 640 1-wire channels in a single mainframe. The 34921A also offers 4 channels for directly
measuring current. Or if you need more current channels, shunts can be added to the terminal block for
easy current measurements.
The multiplexer modules feature break-before-make connections to ensure that no two signals are
connected to each other during a scan. Or, if you prefer, you can control switching manually to create
Figure 2: 34921A 40-channel armature multiplexer with low thermal offset (bank 2)