This part is a kind of semiconductor called 74221.

Function of this product has Dual Non-Retriggerable Monostable Multivibrator.

Manufacturers : Fairchild Semiconductor

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MM74HC221A Dual Non-Retriggerable Monostable Multivibrator September 1983 Revised February 1999 MM74HC221A Dual Non-Retriggerable Monostable Multivibrator General Description The MM74HC221A high speed monostable multivibrators (one shots) utilize advanced silicon-gate CMOS technology. They feature speeds comparable to low power Schottky TTL circuitry while retaining the low power and high noise immunity characteristic of CMOS circuits. Each multivibrator 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. The MM74HC221A is a non-retrig [ ... ]

74221 PDF Datasheet Download