2
Switch Configuration
20
Keysight U7108x and U7110x Operating and Service Manual
TTL Drive (Option 300 and Option 500)
1
Connect pin 1 to supply voltage (24 Vdc) and pin 23 to ground.
2
Select (close) desired RF path by applying ground to the corresponding “drive” pin; for example
apply TTL “High” to pin 3 to close RF path 1.
3
To select another RF path, ensure that all unwanted RF path “drive” pins are at TTL “Low” (to
prevent multiple RF path engagement). Apply TTL “High” to the “drive” pin which corresponds
to the desired RF path.
4
To open all RF paths, ensure that all RF path drive” pins are at TTL “Low”. Then, apply TTL
“High” to pin.
NOTE
Pin 23 must always be connected to ground to enable the electronic position-indicating circuitry
and drive logic circuitry.
In addition to the quiescent current supplying the electronic position-sensing circuitry, the drive
current flows out of pin 23 (during switching) on TTL drive switches (option 300 and option 500).
CAUTION
If pin 23 is not connected to power supply ground, catastrophic failure will occur.
NOTE
After the RF path is switched and latched, the drive current is interrupted by the electronic
position-sensing circuitry. Pulsed control is not necessary, but if implemented, the pulse width
must be 20 ms minimum to ensure the switch is fully latched.
