20 | Keysight | 34980A Multifunction Switch/Measure Unit - Data Sheet
34945A/34945EXT microwave switch/attenuator driver
General speciꢀcations
34945EXT switch drive
(64 channels, low side drive mode)
This module allows you to control switches attenuators, and other devices ex-
ternal to the 34980A. The 34945A/ 34945EXT provides the power and control
signals for many of the most popular microwave switches and attenuators. One
34945A/34945EXT combination can drive up to 64 switch coils—that’s 32 standard
SPDT switches. The 34945A/EXT can be extended by adding additional 34945EXT
boards. The ꢁrst 34945EXT is powered by the mainframe. You can add up to seven
additional 34945EXT boards with user supplied power. Multiple switch operations are
performed in sequential order, or for faster, simultaneous switching, you can connect
an external power supply to the 34945EXT.
Driver off voltage (max)
30 V
Driver off leakage current 500 μA
Driver on current (max)
Driver on voltage (max)
34945EXT switch drive
600 mA
0.5 V @ 600 mA
(64 channels, TTL drive mode)
Hi output voltage
Lo output voltage
Lo input Current
3 V @ Iout = 2 mA
The Y1150A-Y1155A distribution boards enable simple connections to the external
switches. The distribution boards plug onto the 34945EXT and are used to route the
power and control signals from the driver module to the switches using standard
cables.
0.4 V @ Iin = 20 mA
20 mA
34945EXT position indicator sense inputs
Channels
64
The 34945A/34945EXT also has sensing capabilities that allows read back of the
actual position of the switch or attenuator. Drive signals for LED indicators are also
provided to give a visual indication of the switch position.
Lo input voltage (max)
Hi input voltage (min)
Input resistance
0.8 V
2.5 V
>100 kΩ @ Vin ≤ 5 V
>20 kΩ @ Vin > 5 V
30 V
The following microwave switches and attenuators are supported with the
Y1150AY1155A distribution boards:
– N181x/U9397x series SPDT switches
– 8762/3/4 series SPDT switches (screw terminals)
– 8765x coaxial switches
– 8766x/8767x/8768x multiport switches
– 87104x/106x/L710xx/L720xx multiport switches
– 87406x series matrix switches
– 87204x/206x series multiport switches
– 87606x series matrix switches
– 87222x/L7222 transfer switches
– 849x and 8490x series attenuators
– Other switches and devices through individual screw terminal connections
Maximum input voltage
34945EXT switch drive power supply
(34945EXT powered by 34945A)
Voltage
24 V nominal
(external power
supply required for
switches needing
more than 24 V)
Current
100 mA continuous
+ 200 mA
(15 msec pulse,
25% duty cycle)
34945EXT external power connection
Voltage range
Current limit
4.75 V to 30 V
2 A
34945A module
Y1150A-Y1155A
distribution boards
required to control
switches (ordered separate)
LED indicator (Current mode divers)
Channels
64
Supply voltage
LED drive current
5 V nominal
5 mA nominal
(prog 1-20 mA)
34945EXT extender
holds 4 distribution boar
Driver compliance voltage 0.8 V
34945EXT dimensions
11.2" x 4.5" x 1.5" high with distribution boards
installed
Maximum 8 34945 Ext’s per mainframe
Switch drive control also available in L4445A
and L4490A/91A RF Switch Platform.
Figure 12. 34945A/34945EXT
microwave switch/attenuator driver
NOTE: See Application Note, “Conꢁguring
an RF/Microwave Switch System,” literature
number 5989-2272EN, for conꢁguration
details.
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