TLF6538

June 1989

54121DM54121DM74121 One-Shot with

Clear and Complementary Outputs

General Description

The DM5474121 is a monostable multivibrator featuring

both positive and negative edge triggering with complemen-

tary outputs An internal 2kX timing resistor is provided for

design convenience minimizing component count and lay-

out problems This device can be used with a single external

capacitor Inputs (A) are active-low trigger transition inputs

and input (B) is an active-high transition Schmitt-trigger in-

put that allows jitter-free triggering from inputs with tran-

sition rates as slow as 1 voltsecond A high immunity to

cuitry at the input stage

To obtain optimum and trouble free operation please read

operating rules and NSC one-shot application notes careful-

ly and observe recommendations

Features

Y

Triggered from active-high transition or active-low tran-

sition inputs

Y

Variable pulse width from 30 ns to 28 seconds

Y

Jitter free Schmitt-trigger input

Y

Excellent noise immunity typically 12V

Y

Stable pulse width up to 90% duty cycle

Y

TTL DTL compatible

Y

Y

Input clamp diodes

Y

Alternate MilitaryAerospace device (54121) is avail-

able Contact a National Semiconductor Sales Office

Distributor for specifications

Functional Description

The basic output pulse width is determined by selection of

dependent of further transitions of the inputs and is a func-

tion of the timing components Pulse width can vary from a

few nano-seconds to 28 seconds by choosing appropriate

the device two negative edge-triggering (A) inputs one pos-

itive edge Schmitt-triggering (B) input

Connection Diagram

Dual-In-Line Package

TLF6538 – 1

Order Number 54121DMQB 54121FMQB

DM54121J DM54121W or DM74121N

See NS Package Number J14A N14A or W14B

Function Table

Inputs

Outputs

A1

A2

B

Q

Q

LX

H

L

H

XL

H

L

H

XX

L

L

H

HH

X

L

H

H

v

H

v

HH

vv

H

LX

u

XL

u

H

e

High Logic Level

L

e

Low Logic Level

X

e

Can Be Either Low or High

e

A Positive Pulse

e

A Negative Pulse

C1995 National Semiconductor Corporation

RRD-B30M105Printed in U S A