November 1987
Revised January 1999
MM74C221 Dual Monosta
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© 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
external timing components C
EXT
and R
EXT
. The pulse
width is stable over a wide range of temperature and V
CC
.
Pulse stability will be limited by the accuracy of external
timing components. The pulse width is approximately
defined by the relationship t
W(OUT)
≈ C
EXT
R
EXT
. For fur-
ther information and applications, see AN-138.
Features
a73 Wide supply voltage range: 4.5V to 15V
a73 Guaranteed noise margin: 1.0V
a73 High noise immunity: 0.45 V
CC
(typ.)
a73 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 c12 = One HIGH level pulse
L = LOW Level c13 = 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 XLH
X HX
XXLLH
HL↑ c12c13
H ↓ H c12c13