This document is a product specification sheet, which introduces the 74HC/HCT221 dual non-retriggerable monostable multivibrator with reset. The features include low pulse width variance, pin-out identical to '123', overriding reset to terminate output pulse, hysteresis on nB inputs for improved noise immunity, etc.
The Philips 74HC/HCT221 is a dual non‑retriggerable monostable multivibrator available in both HC and HCT CMOS families. Each section provides an active‑LOW‑going edge input (nA) and an active‑HIGH‑going edge input (nB) with Schmitt‑trigger hysteresis for noise immunity, and an overriding active‑LOW reset input (nRD) that terminates the output pulse.
The datasheet details pin assignments, functional diagrams, timing relationships, DC and AC characteristics, and package outlines. It also includes recommended external timing components, power‑down protection guidance, and ordering information for designers integrating the device into digital logic circuits.