I just purchased a A* 32U4 Mini SV and it is pretty nice board.
But there is a little detail unclear, the schematics does not give full clarity of the /SHDN input pin.
There is a NPN transistor Q1 that inverts the signal and drives the enable pin of the buck switcher.
Trouble is with the gate biasing resistors that has no values. I tried to follow the tracks on the PCB and to me it looks like those resistors do not exist at all!
Guide just says pull high this pin to shutdown the regulator but what is the actual voltage for high state? Is it 5V? What is a safe maximum input voltage?
In my opinion there really should be a current limiting resistor at the gate, like 100k. Or, are the resistors somehow built-in to the transistor Q1? Or could it actually be a MOSFET, I could not find what is the part number.