Atec Agilent-34980A - Manual (Page 15)

34945A/34945EXT microwave
switch/attenuator driver
This module allows you to control
switches attenuators, and other
devices external to the 34980A.
The 34945A 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. You can add up to seven
more 34945EXT boards with external
power to drive up to 512 coils from a
single mainframe. Multiple switch
operations are performed in sequential
order, or for faster, simultaneous
switching, you can connect an external
power supply to the 34945EXT.
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.
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.
The following microwave switches
and attenuators are supported with
the distribution boards:
• N181x series SPDT switches
• 876x series SPDT switches (screw
terminals)
• 87104x/106x multiport switches
• 87406x series matrix switches
• 87204x/206x series multiport
switches
• 87606x series matrix switches
• 87222x transfer switches
• 849x series attenuators
• 8490x series attenuators
• Generic screw terminal connections
General specifications—preliminary
34945EXT switch drive
(64 channels, low side drive mode)
Driver off voltage (max) 30V
Driver off leakage current < 10 uA
Driver on current
(continuous; 6 chans) 300 mA
(15 msec, 25% d.c.) 600 mA T
amb
≤ 40°C
400 mA T
amb
> 40°C
Driver on voltage (max) 1.2 V
34945EXT switch drive
(64 channels, TTL drive mode)
Hi output voltage 3 V
Hi output current 2 mA
Lo output voltage 0.4 V
Lo input Current 20 mA
34945EXT position indicator sense inputs
Channels 64
Lo input voltage (max) 0.8 V
Hi input voltage (min) 2.5 V
Input resistance 100 k Ω
Maximum input voltage 30 V
34945EXT switch drive power supply
(34945EXT powered by 34945A)
Voltage 24 V nominal
Current 100 mA continuous +
200 mA (15 msec pulse,
25% duty cycle)
34945EXT external power connection
Voltage range 4.75 V to 30 V
Current limit 2 A
LED indicators
Channels 64
Supply voltage 5 V nominal
LED drive current 10 mA nominal
Compliance voltage 0.8 V
15
Figure 9. 34945A/34945EXT microwave switch/attenuator driver