Thanks Beebop... Im looking at the PICDEM FS USB User Guide at the schematic. Im wondering what they use that mosfet for. Looks like it blocks the VBUS (+) from the rest of the circuit if the user supplies power via adapter. Would that be correct?
Sound correct to me. With no voltage at pin 3 of the regulator, the gate is pulled down to ground by R22. When the user plugs in an adapter there is a positive potential on the gate which shuts down the fet. Quite an idea; I'll have to remember that one.