MM74HC221A - Dual Non-Retriggerable Monostable Multivibrator
MM74HC221A Features
* both a negative, A, and a positive, B, transition triggered input, either of which can be used as an inhibit input. Also included is a clear input that when taken low resets the one shot. The MM74HC221A can be triggered on the positive transition of the clear while A is held LOW and B is held HIGH.