November 1987

Revised January 1999

© 1999 Fairchild Semiconductor Corporation

DS005904.prf

www.fairchildsemi.com

MM74C221

Dual Monostable Multivibrator

General Description

The MM74C221 dual monostable multivibrator is a mono-

lithic complementary MOS integrated circuit. Each multivi-

brator features a negative-transition-triggered input and a

positive-transition-triggered input, either of which can be

used as an inhibit input, and a clear input.

Once fired, the output pulses are independent of further

transitions of the A and B inputs and are a function of the

Pulse stability will be limited by the accuracy of external

timing components. The pulse width is approximately

ther information and applications, see AN-138.

Features

s Wide supply voltage range:

4.5V to 15V

s Guaranteed noise margin: 1.0V

s Low power TTL compatibility: fan out of 2 driving 74L

Ordering Code:

Connection Diagrams

Timing Component

Pin Assignments for DIP

Top View

Truth Table

H

= HIGH Level

 = One HIGH level pulse

L

= LOW Level

= One LOW level pulse

↑ = Transition from LOW-to-HIGH

X

= Irrelevant

↓ = Transition from HIGH-to-LOW

Order Number

Package Number

Package Description

74MMC221N

N16E

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

Inputs

Outputs

Clear

A

B

Q

Q

LX

X

L

H

X

H

X

L

H

XX

L

L

H

HL

↑



H

↓

H