Functional Description
• Dual Monostable Multivibrator

General
The 74HC4538D is a high speed CMOS MONOSTABLE MULTIVIBRATOR fabricated with silicon gate C2MOS
technology.
It achieves the high speed operation similar to equivalent LSTTL while maintaining the CMOS low power
dissipation.
There are two trigger inputs, A input (positive edge input), and B input (negative edge input). These inputs are
valid for a slow rise/fall time signal (tr = tf = 1 s) as they are schmitt trigger inputs.
After triggering, the output stays in a MONOSTABLE state for the time period determined by the external
resistor and capacitor (RX, CX). A low level at CD input breaks this STABLE STATE. In the MONOSTABLE
state, if a new trigger is applied, it makes the MONOSTABLE period longer (retrigger mode).
Limitations for CX and RX are as follows:
External capacitor CX.........No limitation
External resistor RX...........VCC = 2.0 V more than 5 kΩ
VCC = 3.0 V more than 1 kΩ
All inputs are equipped with protection circuits against static discharge or transient excess voltage.

Features (Note)
(1) High speed: tpd = 25 ns (typ.) at VCC = 5 V
(2) Low power dissipation:
Standby state: ICC = 4.0 μA (max) at Ta = 25 
Active state: ICC = 350 μA (max) at Ta = 25 
(3) Balanced propagation delays: tPLH ≈ tPHL
(4) Wide operating voltage range: VCC(opr) = 2.0 to 6.0 V