87104A RF Switch Driver

[PerArdua]

I have bought a single 87104A RF Switch, and need to build a circuit to drive it.

The datasheet for this device (https://www.keysight.com/us/en/assets/7018-06804/technical-overviews/5091-3366.pdf) gives the following steps for operating it (the non-TTL version):
• Connect pin 1 to supply (+20 VDC to +32 VDC).
• Connect pin 15 to ground.
• Select (close) desired RF path by applying ground to the corresponding “drive” pin; for example ground pin 3 to close RF path 1.

I do not have any relays to do this, but would prefer a solid state solution. Does anyone know if these pins carry the supply current to GND (200mA per connection)? If so, does this current last for a moment, or continuously whilst the contact is made? I am thinking of using something like the DMN6140L as a low side switch between pins and GND - a low Rdson, 5V compatible, etc.

[Revky27]

I have bought a single 87104A RF Switch, and need to build a circuit to drive it.

The datasheet for this device (https://www.keysight.com/us/en/assets/7018-06804/technical-overviews/5091-3366.pdf) gives the following steps for operating it (the non-TTL version):
• Connect pin 1 to supply (+20 VDC to +32 VDC).
• Connect pin 15 to ground.
• Select (close) desired RF path by applying ground to the corresponding “drive” pin; for example ground pin 3 to close RF path 1.

I do not have any relays to do this, but would prefer a solid state solution. Does anyone know if these pins carry the supply current to GND (200mA per connection)? If so, does this current last for a moment, or continuously whilst the contact is made? I am thinking of using something like the DMN6140L as a low side switch between pins and GND - a low Rdson, 5V compatible, etc.

Yes I believe the standard drive you need a low side driver for each which directly controls the coil current. You can use a typical low side driver for this: TPL7407LA, however you can find similar which cover the input voltage range up to 32V as this part is only suitable for 24V operation.

The datasheet also specifies that it has magnetic latching and together with this information.
Supply current, Icc Switching: Pulse width ≥ 15 ms: Vcc = 24 VDC1     Option 024 and T24   200  mA

"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 15 ms minimum to ensure that the switch is fully latched. "

To summarize: effectively you will need to drive the pin with a low side driver capable of 200mA for more than 15ms. There is some internal circuitry that once the relay is switched and latched the driver current will stop. You also need to ensure break before make: disconnect the current relay drive before you connect another drive pin to GND.