October 1987

Revised January 1999

© 1999 Fairchild Semiconductor Corporation

DS006000.prf

www.fairchildsemi.com

CD4538BC

Dual Precision Monostable

General Description

The CD4538BC is a dual, precision monostable multivibra-

tor with independent trigger and reset controls. The device

is retriggerable and resettable, and the control inputs are

internally latched. Two trigger inputs are provided to allow

either rising or falling edge triggering. The reset inputs are

active LOW and prevent triggering while active. Precise

control of output pulse-width has been achieved using lin-

ear CMOS techniques. The pulse duration and accuracy

device does not allow the timing capacitor to discharge

through the timing pin on power-down condition. For this

reason, no external protection resistor is required in series

with the timing pin. Input protection from static discharge is

provided on all pins.

Features

s Wide supply voltage range:

3.0V to 15V

s Low power TTL compatibility: Fan out of 2 driving 74L

or 1 driving 74LS

C in Farads)

s

±1.0% pulse-width variation from part to part (typ.)

s Wide pulse-width range: 1

µs to ∞

s Separate latched reset inputs

s Symmetrical output sink and source capability

s Pin compatible to CD4528BC

Ordering Code:

Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.

Connection Diagram

Pin Assignments for DIP and SOIC

Top View

Truth Table

H

= HIGH Level

L

= LOW Level

↑ = Transition from LOW-to-HIGH

↓ = Transition from HIGH-to-LOW

 = One HIGH Level Pulse

= One LOW Level Pulse

X

= Irrelevant

Order Number

Package Number

Package Description

CD4538BCM

M16A

16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150” Narrow Body

CD4538BCWM

M16B

16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300” Wide Body

CD4538BCN

N16E

16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300” Wide

Inputs

Outputs

Clear

A

B

Q

Q

LX

X

L

H

XH

X

L

H

XX

L

L

H

HL

↓



H

↑

H