I think the 10 mSec requirement is EASILY met with just the AND gate (being used as a low input NOR gate....see here).

It will turn out that if the user presses the key and the unit does not turn on if they release before 10 or 20 milliseconds they will just press down hard on the key again most likely for a time far in excess of several hundred milliseconds. (Plus it will be rare to find the person that can press and release a switch within 10 or 20 milliseconds). The extra circuitry would never be needed in this type case in my opinion. It the switch bounces on the initial press then so what, the power up recovery process starts during the time the bouncing stops. It would be an important issue if the wake up interrupt came from some external pulsed signal that had minimal pulse width. In those cases it is desireable to use an R/S type latch and let the wakeup signal set the latch. The set state on the Q-not side of the latch flipflop then drives the processor -INT input. Lastly an acknowledgement signal can come from another port pin to reset the latch. This resetting port pin can also be used as a lockout in special cases where it is desired to disable the wakeup from the external signal.

Michael Karas