74HC123; 74HCT123
Dual retriggerable monostable multivibrator with reset
Rev. 10 — 3 December 2015
Product data sheet
1. General description
The 74HC123; 74HCT123 are high-speed Si-gate CMOS devices and are pin compatible
with Low-power Schottky TTL (LSTTL). They are specified in compliance with JEDEC
standard no. 7A.
The 74HC123; 74HCT123 are dual retriggerable monostable multivibrators with output
pulse width control by three methods:
1. The basic pulse is programmed by selection of an external resistor (R
EXT
) and
capacitor (C
EXT
).
2. Once triggered, the basic output pulse width may be extended by retriggering the
gated active LOW-going edge input (nA) or the active HIGH-going edge input (nB). By
repeating this process, the output pulse period (nQ = HIGH, nQ = 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 nRD, which also inhibits the triggering.
3. An internal connection from nRD to the input gates makes it possible to trigger the
circuit by a HIGH-going signal at input nRD as shown in
Table 3.
Schmitt-trigger action in the nA and nB inputs, makes the circuit highly tolerant to slower
input rise and fall times.
The 74HC123; 74HCT123 are identical to the 74HC423; 74HCT423 but can be triggered
via the reset input.
2. Features and benefits
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
ESD protection:
HBM JESD22-A114F exceeds 2000 V
MM JESD22-A115-A exceeds 200 V
Specified from
40 C
to +85
C
and from
40 C
to +125
C
Nexperia
74HC123; 74HCT123
Dual retriggerable monostable multivibrator with reset
3. Ordering information
Table 1.
Ordering information
Package
Temperature range
74HC123D
74HCT123D
74HC123DB
74HCT123DB
74HC123PW
74HCT123PW
74HC123BQ
40 C
to +125
C
DHVQFN16
40 C
to +125
C
TSSOP16
40 C
to +125
C
SSOP16
40 C
to +125
C
Name
SO16
Description
plastic small outline package; 16 leads;
body width 3.9 mm
plastic shrink small outline package; 16 leads;
body width 5.3 mm
plastic thin shrink small outline package; 16 leads;
body width 4.4 mm
plastic dual in-line compatible thermal enhanced
very thin quad flat package; no leads; 16 terminals;
body 2.5
3.5
0.85 mm
Version
SOT109-1
SOT338-1
SOT403-1
SOT763-1
Type number
4. Functional diagram
Fig 1.
Functional diagram
74HC_HCT123
All information provided in this document is subject to legal disclaimers.
©
Nexperia B.V. 2017. All rights reserved
Product data sheet
Rev. 10 — 3 December 2015
2 of 24
Nexperia
74HC123; 74HCT123
Dual retriggerable monostable multivibrator with reset
Fig 2.
Logic symbol
Fig 3.
IEC logic symbol
Fig 4.
74HC_HCT123
Logic diagram
All information provided in this document is subject to legal disclaimers.
©
Nexperia B.V. 2017. All rights reserved
Product data sheet
Rev. 10 — 3 December 2015
3 of 24
Nexperia
74HC123; 74HCT123
Dual retriggerable monostable multivibrator with reset
5. Pinning information
5.1 Pinning
(1) This is not a supply pin. The substrate is attached to this
pad using conductive die attach material. There is no
electrical or mechanical requirement to solder this pad.
However, if it is soldered, the solder land should remain
floating or be connected to V
CC
.
Fig 5.
Pin configuration for SO16, SSOP16 and
TSSOP16
Fig 6.
Pin configuration for DHVQFN16
5.2 Pin description
Table 2.
Symbol
1A
1B
1RD
1Q
2Q
2CEXT
2REXT/CEXT
GND
2A
2B
2RD
2Q
1Q
1CEXT
1REXT/CEXT
V
CC
74HC_HCT123
Pin description
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Description
negative-edge triggered input 1
positive-edge triggered input 1
direct reset LOW and positive-edge triggered input 1
active LOW output 1
active HIGH output 2
external capacitor connection 2
external resistor and capacitor connection 2
ground (0 V)
negative-edge triggered input 2
positive-edge triggered input 2
direct reset LOW and positive-edge triggered input 2
active LOW output 2
active HIGH output 1
external capacitor connection 1
external resistor and capacitor connection 1
supply voltage
All information provided in this document is subject to legal disclaimers.
©
Nexperia B.V. 2017. All rights reserved
Product data sheet
Rev. 10 — 3 December 2015
4 of 24
Nexperia
74HC123; 74HCT123
Dual retriggerable monostable multivibrator with reset
6. Functional description
Table 3.
Input
nRD
L
X
X
H
H
[1]
Function table
[1]
Output
nA
X
H
X
L
L
nB
X
X
L
H
H
nQ
L
L
[2]
L
[2]
nQ
H
H
[2]
H
[2]
H = HIGH voltage level; L = LOW voltage level; X = don’t 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.
7. Limiting values
Table 4.
Limiting values
In accordance with the Absolute Maximum Rating System (IEC 60134). Voltages are referenced to GND (ground = 0 V).
Symbol
V
CC
I
IK
I
OK
I
O
I
CC
I
GND
T
stg
P
tot
Parameter
supply voltage
input clamping current
output clamping current
output current
supply current
ground current
storage temperature
total power dissipation
SO16 package
SSOP16 package
TSSOP16 package
DHVQFN16 package
[1]
[2]
[3]
For SO16 package: P
tot
derates linearly with 8 mW/K above 70
C.
For SSOP16 and TSSOP16 packages: P
tot
derates linearly with 5.5 mW/K above 60
C.
For DHVQFN16 package: P
tot
derates linearly with 4.5 mW/K above 60
C.
[1]
[2]
[2]
[3]
Conditions
V
I
<
0.5
V or V
I
> V
CC
+ 0.5 V
V
O
<
0.5
V or V
O
> V
CC
+ 0.5 V
except for pins nREXT/CEXT;
V
O
=
0.5
V to (V
CC
+ 0.5 V)
Min
0.5
-
-
-
-
-
65
-
-
-
-
Max
+7
20
20
25
50
50
+150
500
500
500
500
Unit
V
mA
mA
mA
mA
mA
C
mW
mW
mW
mW
74HC_HCT123
All information provided in this document is subject to legal disclaimers.
©
Nexperia B.V. 2017. All rights reserved
Product data sheet
Rev. 10 — 3 December 2015
5 of 24
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