74HC123A View Datasheet(PDF) - Fairchild Semiconductor

Part Name

Description

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74HC123A

Dual Retriggerable Monostable Multivibrator

Fairchild Semiconductor 

September 1983

Revised February 1999

MM74HC123A

Dual Retriggerable Monostable Multivibrator

General Description

The MM74HC123A high speed monostable multivibrators

(one shots) utilize advanced silicon-gate CMOS technol-

ogy. They feature speeds comparable to low power Schot-

tky TTL circuitry while retaining the low power and high

noise immunity characteristic of CMOS circuits.

Each multivibrator features both a negative, A, and a posi-

tive, B, transition triggered input, either of which can be

used as an inhibit input. Also included is a clear input that

when taken low resets the one shot. The MM74HC123A

can be triggered on the positive transition of the clear while

A is held LOW and B is held HIGH.

The MM74HC123A is retriggerable. That is it may be trig-

gered repeatedly while their outputs are generating a pulse

and the pulse will be extended.

Pulse width stability over a wide range of temperature and

supply is achieved using linear CMOS techniques. The out-

put pulse equation is simply: PW = (REXT) (CEXT); where

PW is in seconds, R is in ohms, and C is in farads. All

inputs are protected from damage due to static discharge

by diodes to VCC and ground.

Features

s Typical propagation delay: 25 ns

s Wide power supply range: 2V–6V

s Low quiescent current: 80 µA maximum (74HC Series)

s Low input current: 1 µA maximum

s Fanout of 10 LS-TTL loads

s Simple pulse width formula T = RC

s Wide pulse range: 400 ns to ∞ (typ)

s Part to part variation: ±5% (typ)

s Schmitt Trigger A & B inputs enable infinite signal input

rise and fall times.

Ordering Code:

Order Number Package Number

Package Description

MM74HC123AM

M16A

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

MM74HC123ASJ

M16D

16-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide

MM74HC123AMTC

MTC16

16-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide

MM74HC123AN

N16E

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

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

Connection Diagram

Timing Component

Pin Assignment for DIP, SOIC, SOP and TSSOP

Note: Pin 6 and Pin 14 must be hard-wired to GND.

Top View

© 1999 Fairchild Semiconductor Corporation DS005206.prf

www.fairchildsemi.com

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