Hi all,

Would just like a quick bit of advise.

I am working on a fairly complicated instrument which includes SBC, DSP,
PLD, various digital circuits, 24 bit ADC, various analogue circuits. My
problem is that I would like to be able to turn "off" all the circuitry
but the SBC, using a 3.3V GPIO on the device.

My first thought was this is simple, logic lever N type FETS used as low
side switches to completely cut the power to the various circuits. Then
I thought that this could be a problem with the analogue circuitry and
ADC as these need a good connection to the analogue ground plane.

Would it be better to use a high side switch? If so how? I know that you
use P type FETS, but have never done it.

My other problems/thoughts were that P types are generally more
expensive, and this thing costs enough already! And that I can only
afford to use a single GPIO (not many left).

Hope someone can comment/help,

Kind regards

Graham North

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