I'm trying to switch power to a GSM module with a MOSFET because the OFF state of the module is still like 80uA, which I think I can reduce significantly. I'm thinking the best way to do this is with a P-channel MOSFET that I switch directly with an Arduino pin. With a high-side switch like this I need to use a pull-up resistor between the MOSFET gate and the source to prevent floating logic. However, I'm wondering if I can just set the Arduino to be normally HIGH on the gate pin and remove the resistor, because when the Arduino switches to low there will be parasitic current through the pull-up resistor, which would be something like 0.4mA. So I'm thinking to just remove the pull-up resistor and just control the gate logic so that it's never floating.
One thing though: the Arduino will be going to sleep most of the time, but won't the pins stay at the last value before it went to sleep? For example, if the pin was set HIGH, it will remain HIGH with the Arduino sleeping?
Is this a bad idea? Thanks!