High Side Power switch as a Relay

[Jeff Weinmann]

Hello all,

I'm creating a series of low pass filters that will be used in a HAM WSPR project.   The maximum current I'll be using is around 200 milliamps.   I will have a need for a microcontroller (PIC18) to switch between 4 low pass filters that will clean up HF output frequency square wave to a nice sine wave.

Traditionally people have used mechanical or solid state relays to switch between the low pass filters.  I want to use 4 of these guys to do the same thing:

https://www.digikey.com/ordering/shoppingcart?qty=24&cref=&enterprise=0&part=576-3006-1-ND&partid=1834815&source=search&lang=en


These will all be connected to a PIC via PORTB and I will be able to turn them on and off via code.

Does anyone see a problem of using these instead of a solid state or mechanical relay?   

Thanks

Jeff

[David Hess]

Do you mean to use them alone?  High side power switches have their power and input pins shared so are not suitable for switching variable inputs.

[ajb]

Also look at the diagram in the first page of the datasheet and note the diode in parallel with the pass transistor.  These will not prevent current from flowing from the load side to the input side, so are not suitable for AC applications.

[David Hess]

Also look at the diagram in the first page of the datasheet and note the diode in parallel with the pass transistor.  These will not prevent current from flowing from the load side to the input side, so are not suitable for AC applications.

There are ways to bias RF switches so that the body diode is not a factor.

[SiliconWizard]

Also look at the diagram in the first page of the datasheet and note the diode in parallel with the pass transistor.  These will not prevent current from flowing from the load side to the input side, so are not suitable for AC applications.

There are ways to bias RF switches so that the body diode is not a factor.

How would you do it here?

[David Hess]

Also look at the diagram in the first page of the datasheet and note the diode in parallel with the pass transistor.  These will not prevent current from flowing from the load side to the input side, so are not suitable for AC applications.

There are ways to bias RF switches so that the body diode is not a factor.

How would you do it here?

You would not for the reason I gave in my first post; assuming that the part's performance was otherwise suitable, which I doubt but it is possible, the high side switch has power and input connections shared on one pin preventing it.

[SiliconWizard]

Indeed.
The OP could take a look at this: https://www.analog.com/en/parametricsearch/10725#/