MM74HC123A Dual Retriggerable Monostable Multivibrator
September 1983
Revised May 2001
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
=
(R
EXT
) (C
EXT
); 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 V
CC
and ground.
Features
s
Typical propagation delay: 25 ns
s
Wide power supply range: 2V鈥?V
s
Low quiescent current: 80
碌
A maximum (74HC Series)
s
Low input current: 1
碌
A maximum
s
Fanout of 10 LS-TTL loads
s
Simple pulse width formula T
=
RC
s
Wide pulse range: 400 ns to
鈭?/div>
(typ)
s
Part to part variation:
鹵
5% (typ)
s
Schmitt Trigger A & B inputs allow rise and fall times to
be as slow as one second
Ordering Code:
Order Number
MM74HC123AM
MM74HC123ASJ
MM74HC123AMTC
MM74HC123AN
Package Number
M16A
M16D
MTC16
N16E
Package Description
16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150" Narrow
16-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide
16-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide
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 鈥淴鈥?to the ordering code.
Connection Diagram
Timing Component
Note:
Pin 6 and Pin 14 must be hard-wired to GND.
Top View
漏 2001 Fairchild Semiconductor Corporation
DS005206
www.fairchildsemi.com
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