UNISONIC TECHNOLOGIES CO., LTD
U74HC123
DUAL RETRIGGERABLE
MONOSTABLE
MULTIVIBRATOR WITH
RESET
SOP-16
DESCRIPTION
CMOS IC
The
U74HC123
is high-speed Si-gate CMOS device and is pin
compatible with low power Schottky TTL (LSTTL).
The U74HC123 is a dual retriggerable monostable
multivibrator with output pulse width control by three methods.
The basic pulse time is programmed by selection of an external
resistor (R
EXT
) and capacitor (C
EXT
).
Once triggered, the basic output pulse width may be extended
by retriggering the gated active LOW-going edge input(
n A
) or
the active HIGH-going edge input (nB). By repeating this process,
TSSOP-16
the output pulse period (nQ=HIGH, n Q =LOW) can be made as long as desired. Alternatively an output delay can be
terminated at any time by a LOW-going edge on input nR
D
, which also inhibits the triggering.
An internal connection from nR
D
to the input gates makes it possible to trigger the circuit by a positive-going
signal at input nR
D
as shown in the function table. The basic output pulse width is essentially determined by the
values of the external timing components R
EXT
and C
EXT
.
Schmitt-trigger action in the
n A
and nB inputs, makes the circuit highly tolerant to slower input rise and fall
times.
FEATURES
* DC triggered from active HIGH or active LOW inputs
* Retriggerable for very long pulses up to 100% duty factor
* Direct reset terminates output pulse
* Schmitt-trigger action on all inputs except for the reset input
ORDERING INFORMATION
Ordering Number
U74HC123G-S16-R
U74HC123G-P16-R
Package
SOP-16
TSSOP-16
Packing
Tape Reel
Tape Reel
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QW-R502-A10.B
U74HC123
MARKING
CMOS IC
PIN CONFIGURATION
FUNCTION TABLE
INPUTS
nR
D
L
X
X
H
H
↑
nA
X
H
X
OUTPUTS
nB
X
X
L
↑
H
H
nQ
L
L(2)
L(2)
nQ
H
H(2)
H(2)
L
↓
L
Notes: 1. H: HIGH voltage level L: LOW voltage level X: don’care
↑:
LOW-to-HIGH transition
↓:
HIGH-to-LOW transition
: one HIGH level output pulse
: one LOW level output pulse
2. If the monostable was triggered before this condition was established, the pulse will continue as
programmed.
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QW-R502-A10.B
U74HC123
ABSOLUTE MAXIMUM RATING
PARAMETER
CMOS IC
SYMBOL
RATINGS
UNIT
Supply Voltage
V
CC
-0.5 ~ 7
V
V
CC
or GND Current
I
CC
±50
mA
Output Current
I
OUT
±25
mA
Input Clamp Current
I
IK
±20
mA
Output Clamp Current
I
OK
±20
mA
Storage Temperature
T
STG
-65 ~ + 150
°C
Note: Absolute maximum ratings are those values beyond which the device could be permanently damaged.
Absolute maximum ratings are stress ratings only and functional device operation is not implied.
RECOMMENDED OPERATING CONDITIONS
SYMBOL
V
CC
V
IH
TEST CONDITIONS
V
CC
=2V
V
CC
=4.5V
V
CC
=6V
V
CC
=2V
V
CC
=4.5V
V
CC
=6V
MIN
2
1.5
3.15
4.2
TYP
5
1.2
2.4
3.2
0.8
2.1
2.8
MAX UNIT
6
V
V
0.5
1.35
1.8
V
CC
V
CC
1000
500
400
+125
PARAMETER
Supply Voltage
High-level Input Voltage
Low-level Input Voltage
Input Voltage
Output Voltage
Input Transition Rise and Fall Rate
nR
D
Input
Ambient Temperature
V
IL
V
IN
V
OUT
△
t/
△
V
V
V
V
ns
°C
0
0
V
CC
=2V
V
CC
=4.5V
V
CC
=6V
-40
+25
T
amb
ELECTRICAL CHARACTERISTICS
(T
A
=25°C , unless otherwise specified)
PARAMETER
SYMBOL
TEST CONDITIONS
V
CC
=2V, I
OH
=-20μA
V
CC
=4.5V, I
OH
=-20μA
V
CC
=6V, I
OH
=-20μA
V
CC
=4.5V, I
OH
=-4mA
V
CC
=6V, I
OH
=-5.2mA
V
CC
=2V, I
OL
=20μA
V
CC
=4.5V, I
OL
=20μA
V
CC
=6V, I
OL
=20μA
V
CC
=4.5V, I
OL
=4mA
V
CC
=6V, I
OL
=5.2mA
V
CC
=6V, V
IN
= V
CC
or GND
V
CC
=6V, V
IN
=V
CC
or GND, I
OUT
=0
MIN
1.9
4.4
5.9
3.98
5.48
TYP MAX UNIT
2
4.5
V
6
4.32
5.81
0
0.1
0
0.1
V
0
0.1
0.15 0.26
0.16 0.26
±0.1
μA
8
μA
3.5
pF
Output Voltage High-Level
V
OH
Output Voltage Low-Level
V
OL
Input Leakage Current
Quiescent Supply Current
Input Capacitance
I
I(LEAK)
I
CC
C
I
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