Integrated Circuit


HEF4528B Dual monostable multivibrator

The HEF4528B is a dual retriggerable-resetable monostable multivibrator. Each multivibrator has an active LOW input (nA), and active HIGH input (nB), an active LOW clear direct input (nCD), an output (nQ) and its complement (nQ), and two external timing component connecting pins (nCEXT, always connected to ground, and nREXT/CEXT).

An external timing capacitor (CEXT) must be connected between nCEXT and nREXT/CEXT and an external resistor (REXT) must be connected between nREXT/CEXT and VDD. The output pulse duration is determined by the external timing components CEXT and REXT. A HIGH-to-LOW transition on nA when nB is LOW or a LOW-to-HIGH transition on nB when nA is HIGH produces a positive pulse (LOW-HIGH-LOW) on nQ and a negative pulse (HIGH-LOW-HIGH) on nQ if the nCD is HIGH. A LOW on nCD forces nQ LOW, nQ HIGH and inhibits any further pulses until nCD is HIGH.

It operates over a recommended VDD power supply range of 3 V to 15 V referenced to VSS (usually ground). Unused inputs must be connected to VDD, VSS, or another input.




  1. HEF4528BP Dual monostable multivibrator