TLF6000

February 1988

CD4538BMCD4538BC Dual Precision Monostable

General Description

The CD4538B is a dual precision monostable multivibrator

with independent trigger and reset controls The device is

retriggerable and resettable and the control inputs are inter-

nally 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 linear CMOS

techniques The pulse duration and accuracy are deter-

not allow the timing capacitor to discharge through the tim-

ing pin on power-down condition For this reason no exter-

nal protection resistor is required in series with the timing

pin Input protection from static discharge is provided on all

pins

Features

Y

Wide supply voltage range

30V to 15V

Y

High noise immunity

Y

Low power

Fan out of 2 driving 74L

TTL compatibility

or 1 driving 74LS

Y

(PW in seconds R in Ohms C in Farads)

Y

g

10% pulse-width variation from part to part (typ)

Y

Wide pulse-width range

1 msto %

Y

Separate latched reset inputs

Y

Symmetrical output sink and source capability

Y

Low standby current

5 nA (typ)

Y

Pin compatible to CD4528B

Block and Connection Diagrams

TLF6000 – 1

Dual-In-Line Package

CD4538BM

CD4538BC

TLF6000 – 2

Top View

Order Number CD4538B

Truth Table

Inputs

Outputs

Clear

A

B

Q

Q

LX

X

L

H

XH

X

L

H

XX

L

L

H

HL

v

H

u

H

H

e

High Level

L

e

Low Level

e

One High Level Pulse

e

One Low Level Pulse

X

e

Irrelevant

C1995 National Semiconductor Corporation

RRD-B30M105Printed in U S A