TLF6539

March 1993

DM54123DM74123 Dual Retriggerable One-Shot with

Clear and Complementary Outputs

General Description

The ’123 is a dual retriggerable monostable multivibrator

capable of generating output pulses from a few nano-sec-

onds to extremely long duration up to 100% duty cycle

Each device has three inputs permitting the choice of either

leading-edge or trailing edge triggering Pin (A) is an active-

low transition trigger input and pin (B) is an active-high tran-

sition trigger input A low at the clear (CLR) input terminates

the output pulse which also inhibits triggering An internal

connection from CLR to the input gate makes it possible to

trigger the circuit by a positive-going signal on CLR as

shown in the truth table

To obtain the best and trouble free operation from this de-

vice please read the operating rules as well as the NSC

one – shot application notes carefully and observe recom-

mendations

Features

Y

DC triggered from active-high transition or active-low

transition inputs

Y

Retriggerable to 100% duty cycle

Y

Direct reset terminates output pulse

Y

Y

DTL TTL compatible

Y

Input clamp diodes

Functional Description

The basic output pulse width is determined by selection of

the basic pulse width may be extended by retriggering the

gated active-low transition or active-high transition inputs or

be reduced by use of the active-low transition clear input

Retriggering to 100% duty cycle is possible by application of

an input pulse train whose cycle time is shorter than the

output cycle time such that a continuous ‘‘HIGH’’ logic state

is maintained at the ‘‘Q’’ output

Connection Diagram

Dual-In-Line Package

TLF6539 – 1

Order Number DM54123J-MIL DM54123W-MIL or DM74123N

See NS Package Number J16A N16A or W16A

Triggering Truth Table

Inputs

Response

A

B

CLR

X

X

L

No Trigger

K

L

X

No Trigger

K

H

H

Trigger

H

L

X

No Trigger

L

L

H

Trigger

LH

L

Trigger

C1995 National Semiconductor Corporation

RRD-B30M105Printed in U S A