TLF6385

May 1989

DM74LS122 Retriggerable One-Shot with

Clear and Complementary Outputs

General Description

The DM74LS122 is a retriggerable monostable multivibrator

featuring both positive and negative edge triggering with

complementary outputs An internal 10 kX timing resistor is

provided for design convenience minimizing component

count and layout problems This device can be used with a

single external capacitor The ’LS122 has two active-low

transition triggering inputs (A) two active-high transition trig-

gering inputs (B) and a CLEAR input that terminates the

output pulse width at a predetermined time independent of

the timing components The clear (CLR) input also serves

as a trigger input when it is pulsed with a low level pulse

transition (

) To obtain optimum and trouble free opera-

tion please read operating rules and NSC one-shot applica-

tion notes carefully and observe recommendations

Features

Y

DC triggered from active-high transition or active-low

transition inputs

Y

Retriggerable to 100% duty cycle

Y

Over-riding clear terminates output pulse

Y

Internal 10 kX timing resistor

Y

TTL DTL compatible

Y

Y

Input clamp diodes

Functional Description

The basic output pulse width is determined by selection of

be extended by retriggering the gated active-low (A) tran-

sition inputs or the active-high transition (B) inputs or the

CLEAR input The output pulse width can be reduced or

terminated by overriding it with the active-low CLEAR input

Connection Diagram

Dual-In-Line Package

TLF6385 – 1

Order Number DM74LS122M or DM74LS122N

See NS Package Number M14A or N14A

Function Table

Inputs

Outputs

CLEAR

A1

A2

B1

B2

Q

Q

LX

X

X

X

L

H

XH

H

X

X

L

H

XX

X

L

X

L

H

XX

X

X

L

L

H

HL

X

u

H

HL

X

H

u

HX

L

u

H

HX

L

H

u

HH

v

HH

H

vv

HH

H

v

HH

H

u

LX

H

H

u

XL

H

H

e

A Positive Pulse

e

A Negative Pulse

C1995 National Semiconductor Corporation

RRD-B30M105Printed in U S A