74LV123
Dual retriggerable monostable multivibrator with reset
Rev. 8 — 4 March 2016
Product data sheet
1. General description
The 74LV123 is a low-voltage Si-gate CMOS device and is pin and function compatible
with the 74HC123; 74HCT123. It is a dual retriggerable monostable multivibrator which
uses three methods to control the output pulse width:
1. The basic pulse time is programmed by the selection of an external resistor (R
EXT
)
and capacitor (C
EXT
). These are normally connected as shown in
Figure 9.
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 (see
Figure 12).
3. Alternatively, an output delay can be terminated at any time by a LOW-going edge on
input nRD, which also inhibits the triggering (see
Figure 13).
Schmitt-trigger action in the nA and nB inputs makes the circuit highly tolerant of slower
input rise and fall times.
2. Features and benefits
Optimized for low-voltage applications: 1.0 V to 5.5 V
Accepts TTL input levels between V
CC
= 2.7 V and V
CC
= 3.6 V
Typical output ground bounce: < 0.8 V at V
CC
= 3.3 V and T
amb
= 25
C
Typical HIGH-level output voltage (V
OH
) undershoot: > 2 V at V
CC
= 3.3 V and
T
amb
= 25
C
DC triggered from active HIGH or active LOW inputs
Retriggerable for very long pulses up to 100 % duty factor
Direct reset terminates output pulses
Schmitt-trigger action on all inputs except for the reset input
Nexperia
74LV123
Dual retriggerable monostable multivibrator with reset
3. Ordering information
Table 1.
Ordering information
Package
Temperature range
74LV123D
74LV123DB
74LV123PW
74LV123BQ
40 C
to +125
C
40 C
to +125
C
40 C
to +125
C
40 C
to +125
C
Name
SO16
SSOP16
TSSOP16
Description
plastic small outline package; 16 leads; body width
3.9 mm
Version
SOT109-1
Type number
plastic shrink small outline package; 16 leads; body width SOT338-1
5.3 mm
plastic thin shrink small outline package; 16 leads; body
width 4.4 mm
SOT403-1
DHVQFN16 plastic dual in-line compatible thermal enhanced very thin SOT763-1
quad flat package; no leads; 16 terminals;
body 2.5
3.5
0.85 mm
4. Functional diagram
Fig 1.
Logic symbol
Fig 2.
IEC logic symbol
74LV123
All information provided in this document is subject to legal disclaimers.
©
Nexperia B.V. 2017. All rights reserved
Product data sheet
Rev. 8 — 4 March 2016
2 of 23
Nexperia
74LV123
Dual retriggerable monostable multivibrator with reset
Fig 3.
Functional diagram
74LV123
All information provided in this document is subject to legal disclaimers.
©
Nexperia B.V. 2017. All rights reserved
Product data sheet
Rev. 8 — 4 March 2016
3 of 23
Nexperia
74LV123
Dual retriggerable monostable multivibrator with reset
Fig 4.
Logic diagram
74LV123
All information provided in this document is subject to legal disclaimers.
©
Nexperia B.V. 2017. All rights reserved
Product data sheet
Rev. 8 — 4 March 2016
4 of 23
Nexperia
74LV123
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 and (T)SSOP16
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
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
74LV123
All information provided in this document is subject to legal disclaimers.
©
Nexperia B.V. 2017. All rights reserved
Product data sheet
Rev. 8 — 4 March 2016
5 of 23
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