74HC123; 74HCT123
Dual retriggerable monostable multivibrator with reset
Rev. 11.1 — 3 September 2020 Product data sheet
1. General description
The 74HC123; 74HCT123 is a dual retriggerable monostable multivibrator with reset. The basic
output pulse width is programmed by selection of external components (REXT and CEXT). Once
triggered this basic pulse width may be extended by retriggering either of the edge triggered
inputs (nA or 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. Inputs include clamp diodes. This enables the use of current
limiting resistors to interface inputs to voltages in excess of VCC.
Schmitt-trigger action in the nA and nB inputs, makes the circuit highly tolerant to slower input rise
and fall times.
2. Features and benefits
Wide supply voltage range from 2.0 V to 6.0 V
CMOS low power dissipation
High noise immunity
Latch-up performance exceeds 100 mA per JESD 78 Class II Level B
Complies with JEDEC standards:
JESD8C (2.7 V to 3.6 V)
JESD7A (2.0 V to 6.0 V)
Input levels:
For 74HC123: CMOS level
For 74HCT123: TTL level
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
Multiple package options
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
PackageType number
Temperature range Name Description Version
74HC123D
74HCT123D
-40 °C to +125 °C SO16 plastic small outline package; 16 leads;
body width 3.9 mm
SOT109-1
74HC123DB
74HCT123DB
-40 °C to +125 °C SSOP16 plastic shrink small outline package; 16 leads;
body width 5.3 mm
SOT338-1
74HC123PW
74HCT123PW
-40 °C to +125 °C TSSOP16 plastic thin shrink small outline package; 16 leads;
body width 4.4 mm
SOT403-1
74HC123BQ -40 °C to +125 °C DHVQFN16 plastic dual in-line compatible thermal
enhanced very thin quad flat package; no leads;
16 terminals; body 2.5 × 3.5 × 0.85 mm
SOT763-1
4. Functional diagram
1Q
Q
2RD
RD
S13
1REXT/CEXT
15
1CEXT
14
1Q
Q4
9
001aaa610
1RD
2A
1
1A
10
2B
2
11
3
1B
T
Q
RD
S
2REXT/CEXT
7
2CEXT
6
2Q
5
Q2Q
12
T
Fig. 1. Functional diagram
74HC_HCT123 All information provided in this document is subject to legal disclaimers. © Nexperia B.V. 2020. All rights reserved
Product data sheet Rev. 11.1 — 3 September 2020 2 / 21
Nexperia 74HC123; 74HCT123
Dual retriggerable monostable multivibrator with reset
1Q
Q
2RD
RD
S
2REXT/CEXT
13
7
1REXT/CEXT 15
2CEXT 6
1CEXT 14
2Q 5
1Q
Q4
2Q 12
9
mna515
1RD
2A
1 1A
10 2B
2
11
3
1B
T
Fig. 2. Logic symbol
mna516
CX
&
6
5
12
RCX
R
7
9
11
10
CX
&
14
13
4
RCX
R
15
1
3
2
Fig. 3. IEC logic symbol
mna518
nREXT/CEXT
VCC
VCC VCC
R
nRD
nA
nB R
CL
CL CL
CL CL
nQ
nQ
R
R
Fig. 4. Logic diagram
74HC_HCT123 All information provided in this document is subject to legal disclaimers. © Nexperia B.V. 2020. All rights reserved
Product data sheet Rev. 11.1 — 3 September 2020 3 / 21
Nexperia 74HC123; 74HCT123
Dual retriggerable monostable multivibrator with reset
5. Pinning information
5.1. Pinning
74HC123
74HCT123
1A VCC
1B 1REXT/CEXT
1RD 1CEXT
1Q 1Q
2Q 2Q
2CEXT 2RD
2REXT/CEXT 2B
GND 2A
001aaa698
1
2
3
4
5
6
7
8
10
9
12
11
14
13
16
15
Fig. 5. Pin configuration SOT109-1 (SO16), SOT338-1
(SSOP16) and SOT403-1 (TSSOP16)
001aaf046
74HC123
2REXT/CEXT 2B
2CEXT 2RD
2Q 2Q
1Q 1Q
1RD 1CEXT
1B 1REXT/CEXT
GND
2A
1A
VCC
Transparent top view
7 10
6 11
5 12
4 13
3 14
2 15
8
9
1
16
terminal 1
index area
VCC(1)
(1) This is not a supply pin. There is no electrical or
mechanical requirement to solder the pad. In case
soldered, the solder land should remain floating or
connected to VCC.
Fig. 6. Pin configuration SOT763-1 (DHVQFN16)
5.2. Pin description
Table 2. Pin description
Symbol Pin Description
1A 1 negative-edge triggered input 1
1B 2 positive-edge triggered input 1
1RD 3 direct reset LOW and positive-edge triggered input 1
1Q 4 active LOW output 1
2Q 5 active HIGH output 2
2CEXT 6 external capacitor connection 2
2REXT/CEXT 7 external resistor and capacitor connection 2
GND 8 ground (0 V)
2A 9 negative-edge triggered input 2
2B 10 positive-edge triggered input 2
2RD 11 direct reset LOW and positive-edge triggered input 2
2Q 12 active LOW output 2
1Q 13 active HIGH output 1
1CEXT 14 external capacitor connection 1
1REXT/CEXT 15 external resistor and capacitor connection 1
VCC 16 supply voltage
74HC_HCT123 All information provided in this document is subject to legal disclaimers. © Nexperia B.V. 2020. All rights reserved
Product data sheet Rev. 11.1 — 3 September 2020 4 / 21
Nexperia 74HC123; 74HCT123
Dual retriggerable monostable multivibrator with reset
6. Functional description
Table 3. Function table
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.
Input Output
nRD nA nB nQ nQ
L X X L H
X H X L [1] H [1]
X X L L [1] H [1]
H L
H H
L H
[1] 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 Parameter Conditions Min Max Unit
VCC supply voltage -0.5 +7 V
IIK input clamping current VI < -0.5 V or VI > VCC + 0.5 V - ±20 mA
IOK output clamping current VO < -0.5 V or VO > VCC + 0.5 V - ±20 mA
IOoutput current except for pins nREXT/CEXT;
VO = -0.5 V to (VCC + 0.5 V)
- ±25 mA
ICC supply current - 50 mA
IGND ground current - -50 mA
Tstg storage temperature -65 +150 °C
Ptot total power dissipation [1] - 500 mW
[1] For SOT109-1 (SO16) package: Ptot derates linearly with 12.4 mW/K above 110 °C.
For SOT338-1 (SSOP16) package: Ptot derates linearly with 8.5 mW/K above 91 °C.
For SOT403-1 (TSSOP16) package: Ptot derates linearly with 8.5 mW/K above 91 °C.
For SOT763-1 (DHVQFN16) package: Ptot derates linearly with 11.2 mW/K above 106 °C.
74HC_HCT123 All information provided in this document is subject to legal disclaimers. © Nexperia B.V. 2020. All rights reserved
Product data sheet Rev. 11.1 — 3 September 2020 5 / 21
Nexperia 74HC123; 74HCT123
Dual retriggerable monostable multivibrator with reset
8. Recommended operating conditions
Table 5. Recommended operating conditions
74HC123 74HCT123Symbol Parameter Conditions
Min Typ Max Min Typ Max
Unit
VCC supply voltage 2.0 5.0 6.0 4.5 5.0 5.5 V
VIinput voltage 0 - VCC 0 - VCC V
VOoutput voltage 0 - VCC 0 - VCC V
nRD input
VCC = 2.0 V - - 625 - - - ns/V
VCC = 4.5 V - 1.67 139 - 1.67 139 ns/V
Δt/ΔV input transition rise and
fall rate
VCC = 6.0 V - - 83 - - - ns/V
Tamb ambient temperature -40 +25 +125 -40 +25 +125 °C
9. Static characteristics
Table 6. Static characteristics
At recommended operating conditions; voltages are referenced to GND (ground = 0 V).
25 °C -40 °C to +85 °C -40 °C to +125 °CSymbol Parameter Conditions
Min Typ Max Min Max Min Max
Unit
74HC123
VCC = 2.0 V 1.5 1.2 - 1.5 - 1.5 - V
VCC = 4.5 V 3.15 2.4 - 3.15 - 3.15 - V
VIH HIGH-level
input voltage
VCC = 6.0 V 4.2 3.2 - 4.2 - 4.2 - V
VCC = 2.0 V - 0.8 0.5 - 0.5 - 0.5 V
VCC = 4.5 V - 2.1 1.35 - 1.35 - 1.35 V
VIL LOW-level
input voltage
VCC = 6.0 V - 2.8 1.8 - 1.8 - 1.8 V
VI = VIH or VIL
IO = -20 μA; VCC = 2.0 V 1.9 2.0 - 1.9 - 1.9 - V
IO = -20 μA; VCC = 4.5 V 4.4 4.5 - 4.4 - 4.4 - V
IO = -20 μA; VCC = 6.0 V 5.9 6.0 - 5.9 - 5.9 - V
IO = -4 mA; VCC = 4.5 V 3.98 4.32 - 3.84 - 3.7 - V
VOH HIGH-level
output voltage
IO = -5.2 mA; VCC = 6.0 V 5.48 5.81 - 5.34 - 5.2 - V
VI = VIH or VIL
IO = 20 μA; VCC = 2.0 V - 0 0.1 - 0.1 - 0.1 V
IO = 20 μA; VCC = 4.5 V - 0 0.1 - 0.1 - 0.1 V
IO = 20 μA; VCC = 6.0 V - 0 0.1 - 0.1 - 0.1 V
IO = 4 mA; VCC = 4.5 V - 0.15 0.26 - 0.33 - 0.4 V
VOL LOW-level
output voltage
IO = 5.2 mA; VCC = 6.0 V - 0.16 0.26 - 0.33 - 0.4 V
IIinput leakage
current
VI = VCC or GND; VCC = 6.0 V - - ±0.1 - ±1.0 - ±1.0 μA
ICC supply current VI = VCC or GND; IO = 0 A;
VCC = 6.0 V
- - 8.0 - 80 - 160 μA
CIinput
capacitance
- 3.5 - - - - - pF
74HC_HCT123 All information provided in this document is subject to legal disclaimers. © Nexperia B.V. 2020. All rights reserved
Product data sheet Rev. 11.1 — 3 September 2020 6 / 21
Nexperia 74HC123; 74HCT123
Dual retriggerable monostable multivibrator with reset
25 °C -40 °C to +85 °C -40 °C to +125 °CSymbol Parameter Conditions
Min Typ Max Min Max Min Max
Unit
74HCT123
VIH HIGH-level
input voltage
VCC = 4.5 V to 5.5 V 2.0 1.6 - 2.0 - 2.0 - V
VIL LOW-level
input voltage
VCC = 4.5 V to 5.5 V - 1.2 0.8 - 0.8 - 0.8 V
VI = VIH or VIL; VCC = 4.5 V
IO = -20 μA 4.4 4.5 - 4.4 - 4.4 - V
VOH HIGH-level
output voltage
IO = -4 mA 3.98 4.32 - 3.84 - 3.7 - V
VI = VIH or VIL; VCC = 4.5 V
IO = 20 μA - 0 0.1 - 0.1 - 0.1 V
VOL LOW-level
output voltage
IO = 4.0 mA - 0.15 0.26 - 0.33 - 0.4 V
IIinput leakage
current
VI = VCC or GND; VCC = 5.5 V - - ±0.1 - ±1.0 - ±1.0 μA
ICC supply current VI = VCC or GND; IO = 0 A;
VCC = 5.5 V
- - 8.0 - 80 - 160 μA
per input pin; IO = 0 A;
VI = VCC - 2.1 V;
other inputs at VCC or GND;
VCC = 4.5 V to 5.5 V
pins nA, nB - 35 125 - 160 - 170 μA
ΔICC additional
supply current
pin nRD - 50 180 - 225 - 245 μA
CIinput
capacitance
- 3.5 - - - - - pF
74HC_HCT123 All information provided in this document is subject to legal disclaimers. © Nexperia B.V. 2020. All rights reserved
Product data sheet Rev. 11.1 — 3 September 2020 7 / 21
Nexperia 74HC123; 74HCT123
Dual retriggerable monostable multivibrator with reset
10. Dynamic characteristics
Table 7. Dynamic characteristics
Voltages are referenced to GND (ground = 0 V); CL = 50 pF unless otherwise specified; for test circuit see Fig. 12.
25 °C -40 °C to +85 °C -40 °C to +125 °CSymbol Parameter Conditions
Min Typ Max Min Max Min Max
Unit
74HC123
nRD, nA, nB to nQ or nQ;
CEXT = 0 pF; REXT = 5 kΩ;
see Fig. 9
[1]
VCC = 2.0 V - 83 255 - 320 - 385 ns
VCC = 4.5 V - 30 51 - 64 - 77 ns
VCC = 5 V; CL = 15 pF - 26 - - - - - ns
VCC = 6.0 V - 24 43 - 54 - 65 ns
nRD (reset) to nQ or nQ;
CEXT = 0 pF; REXT = 5 kΩ;
see Fig. 9
VCC = 2.0 V - 66 215 - 270 - 325 ns
VCC = 4.5 V - 24 43 - 54 - 65 ns
VCC = 5 V; CL = 15 pF - 20 - - - - - ns
tpd propagation
delay
VCC = 6.0 V - 19 37 - 46 - 55 ns
see Fig. 9 [1]
VCC = 2.0 V - 19 75 - 95 - 110 ns
VCC = 4.5 V - 7 15 - 19 - 22 ns
tttransition time
VCC = 6.0 V - 6 13 - 16 - 19 ns
nA LOW; see Fig. 10
VCC = 2.0 V 100 8 - 125 - 150 - ns
VCC = 4.5 V 20 3 - 25 - 30 - ns
VCC = 6.0 V 17 2 - 21 - 26 - ns
nB HIGH; see Fig. 10
VCC = 2.0 V 100 17 - 125 - 150 - ns
VCC = 4.5 V 20 6 - 25 - 30 - ns
VCC = 6.0 V 17 5 - 21 - 26 - ns
nRD LOW; see Fig. 11
VCC = 2.0 V 100 14 - 125 - 150 - ns
VCC = 4.5 V 20 5 - 25 - 30 - ns
VCC = 6.0 V 17 4 - 21 - 26 - ns
nQ HIGH and nQ LOW;
VCC = 5.0 V; see Fig. 10
and Fig. 11
[2]
CEXT = 100 nF;
REXT = 10 kΩ
- 450 - - - - - μs
tWpulse width
CEXT = 0 pF;
REXT = 5 kΩ
- 75 - - - - - ns
trtrig retrigger time nA, nB; CEXT = 0 pF;
REXT = 5 kΩ; VCC = 5.0 V;
see Fig. 10
[3] [4] - 110 - - - - - ns
74HC_HCT123 All information provided in this document is subject to legal disclaimers. © Nexperia B.V. 2020. All rights reserved
Product data sheet Rev. 11.1 — 3 September 2020 8 / 21
Nexperia 74HC123; 74HCT123
Dual retriggerable monostable multivibrator with reset
25 °C -40 °C to +85 °C -40 °C to +125 °CSymbol Parameter Conditions
Min Typ Max Min Max Min Max
Unit
see Fig. 7
VCC = 2.0 V 10 - 1000 - - - -
REXT external timing
resistor
VCC = 5.0 V 2 - 1000 - - - -
CEXT external timing
capacitor
VCC = 5.0 V; see Fig. 7 [4] - - - - - - - pF
CPD power
dissipation
capacitance
per monostable;
VI = GND to VCC
[5] - 54 - - - - - pF
74HCT123
nRD, nA, nB to nQ or nQ;
CEXT = 0 pF; REXT = 5 kΩ;
see Fig. 9
VCC = 4.5 V - 30 51 - 64 - 77 ns
VCC = 5 V; CL = 15 pF - 26 - - - - - ns
nRD (reset) to nQ or nQ;
CEXT = 0 pF; REXT = 5 kΩ;
see Fig. 9
VCC = 4.5 V - 27 46 - 58 - 69 ns
tPHL HIGH to LOW
propagation
delay
VCC = 5 V; CL = 15 pF - 23 - - - - - ns
nRD, nA, nB to nQ or nQ;
CEXT = 0 pF; REXT = 5 kΩ;
see Fig. 9
VCC = 4.5 V - 28 51 - 64 - 77 ns
VCC = 5 V; CL = 15 pF - 26 - - - - - ns
nRD (reset) to nQ or nQ;
CEXT = 0 pF; REXT = 5 kΩ;
see Fig. 9
VCC = 4.5 V - 23 46 - 58 - 69 ns
tPLH LOW to HIGH
propagation
delay
VCC = 5 V; CL = 15 pF - 23 - - - - - ns
tttransition time VCC = 4.5 V; see Fig. 9 [1] - 7 15 - 19 - 22 ns
VCC = 4.5 V
nA LOW; see Fig. 10 20 3 - 25 - 30 - ns
nB HIGH; see Fig. 10 20 5 - 25 - 30 - ns
nRD LOW; see Fig. 11 20 7 - 25 - 30 - ns
nQ HIGH and nQ LOW;
VCC = 5.0 V; see Fig. 10
and Fig. 11
[2]
CEXT = 100 nF;
REXT = 10 kΩ
- 450 - - - - - μs
tWpulse width
CEXT = 0 pF;
REXT = 5 kΩ
- 75 - - - - - ns
trtrig retrigger time nA, nB; CEXT = 0 pF;
REXT = 5 kΩ; VCC = 5.0 V;
see Fig. 10
[3] [4] - 110 - - - - - ns
REXT external timing
resistor
VCC = 5.0 V; see Fig. 7 2 - 1000 - - - -
CEXT external timing
capacitor
VCC = 5.0 V; see Fig. 7 [4] - - - - - - - pF
74HC_HCT123 All information provided in this document is subject to legal disclaimers. © Nexperia B.V. 2020. All rights reserved
Product data sheet Rev. 11.1 — 3 September 2020 9 / 21
Nexperia 74HC123; 74HCT123
Dual retriggerable monostable multivibrator with reset
25 °C -40 °C to +85 °C -40 °C to +125 °CSymbol Parameter Conditions
Min Typ Max Min Max Min Max
Unit
CPD power
dissipation
capacitance
per monostable;
VI = GND to VCC - 1.5 V
[5] - 56 - - - - - pF
[1] tpd is the same as tPHL and tPLH; tt is the same as tTHL and tTLH
[2] For other REXT and CEXT combinations see Fig. 7. If CEXT > 10 nF, the next formula is valid.
tW = K × REXT × CEXT, where:
tW = typical output pulse width in ns;
REXT = external resistor in kΩ;
CEXT = external capacitor in pF;
K = constant = 0.45 for VCC = 5.0 V and 0.55 for VCC = 2.0 V.
The inherent test jig and pin capacitance at pins 15 and 7 (nREXT/CEXT) is approximately 7 pF.
[3] The time to retrigger the monostable multivibrator depends on the values of REXT and CEXT. The output pulse width will only be
extended when the time between the active-going edges of the trigger input pulses meets the minimum retrigger time. If CEXT >10 pF,
the next formula (at VCC = 5.0 V) for the setup time of a retrigger pulse is valid:
trtrig = 30 + 0.19 × REXT × CEXT 0.9 + 13 × REXT 1.05, where:
trtrig = retrigger time in ns;
CEXT = external capacitor in pF; REXT = external resistor in kΩ.
The inherent test jig and pin capacitance at pins 15 and 7 (nREXT/CEXT) is 7 pF.
[4] When the device is powered-up, initiate the device via a reset pulse, when CEXT < 50 pF.
[5] CPD is used to determine the dynamic power dissipation (PD in μW).
PD = CPD x VCC 2 x fi + Σ(CL x VCC 2 x fo) + 0.75 x CEXT x VCC 2 x fo + D x 16 × VCC where:
fi = input frequency in MHz;
fo = output frequency in MHz;
D = duty factor in %;
CL = output load capacitance in pF;
VCC = supply voltage in V;
CEXT = timing capacitance in pF;
Σ(CL x VCC 2 x fo) sum of outputs.
001aaa611
103
102
105
104
106
tW
(ns)
10
CEXT (pF)
1 104
103
10 102
(2)
(3)
(4)
(1)
VCC = 5.0 V; Tamb = 25 °C.
(1) REXT = 100 kΩ
(2) REXT = 50 kΩ
(3) REXT = 10 kΩ
(4) REXT = 2 kΩ
Fig. 7. Typical output pulse width as a function of the
external capacitor value
VCC (V)
0 862 4
001aaa612
0.4
0.2
0.6
0.8
'K' factor
0
CEXT = 10 nF; REXT = 10 kΩ to 100 kΩ.
Tamb = 25 °C.
Fig. 8. 74HC123 typical ‘K’ factor as function of VCC
74HC_HCT123 All information provided in this document is subject to legal disclaimers. © Nexperia B.V. 2020. All rights reserved
Product data sheet Rev. 11.1 — 3 September 2020 10 / 21
Nexperia 74HC123; 74HCT123
Dual retriggerable monostable multivibrator with reset
10.1. Waveforms and test circuit
001aaa771
nB input
tW
tW
tPLH
VM
VOH
VM
VM
tW
tPLH
tTHL
tW
tPHL
tPHL
VM
tW
tPLH
nA input
nRD input
nQ output
nQ output
VM
tTLH
VY
VX
VY
VX
tPHL
tPHL tPLH
(reset)
(reset)
VOL
VOH
VOL
VI
VI
VI
GND
GND
GND
Measurement points are given in Table 8.
VOL and VOH are typical voltage output levels that occur with the output load.
Fig. 9. Propagation delays from inputs (nA, nB, nRD) to outputs (nQ, nQ) and output transition times
mna521
tWtW
tW
tW
tW
nB input
nA input
nQ output
trtrig
nRD = HIGH
Fig. 10. Output pulse control using retrigger pulse
74HC_HCT123 All information provided in this document is subject to legal disclaimers. © Nexperia B.V. 2020. All rights reserved
Product data sheet Rev. 11.1 — 3 September 2020 11 / 21
Nexperia 74HC123; 74HCT123
Dual retriggerable monostable multivibrator with reset
mna522
tWtW
tW
nB input
nRD input
nQ output
nA = LOW
Fig. 11. Output pulse control using reset input nRD
VMVM
tW
tW
10 %
90 %
0 V
VI
VI
negative
pulse
positive
pulse
0 V
VMVM
90 %
10 %
tf
tr
tr
tf
001aad983
DUT
VCC VCC
VIVO
RT
RLS1
CL
open
G
Test data is given in Table 8.
Definitions test circuit:
RT = Termination resistance should be equal to output impedance Zo of the pulse generator.
CL = Load capacitance including jig and probe capacitance.
RL = Load resistance.
S1 = Test selection switch.
Fig. 12. Test circuit for measuring switching times
Table 8. Test data
Input Load S1 positionType
VItr, tfCLRLtPHL, tPLH
74HC123 VCC 6 ns 15 pF, 50 pF 1 kΩ open
74HCT123 3 V 6 ns 15 pF, 50 pF 1 kΩ open
74HC_HCT123 All information provided in this document is subject to legal disclaimers. © Nexperia B.V. 2020. All rights reserved
Product data sheet Rev. 11.1 — 3 September 2020 12 / 21
Nexperia 74HC123; 74HCT123
Dual retriggerable monostable multivibrator with reset
11. Application information
11.1. Timing component connections
The basic output pulse width is essentially determined by the values of the external timing
components REXT and CEXT.
001aaa854
CEXT REXT
nA
nB
VCC
nCEXT
nRD
nREXT/CEXT
nQ
nQ
GND
123 13 (5)
4 (12)
15 (7)14 (6)
3 (11)
8
1 (9)
2 (10)
(1)
(1) For minimum noise generation it is recommended to ground pins 6 (2CEXT) and
14 (1CEXT) externally to pin 8 (GND).
Fig. 13. Timing component connections
11.2. Power-up considerations
When the monostable is powered-up it may produce an output pulse, with a pulse width defined by
the values of REXT and CEXT. This output pulse can be eliminated using the circuit shown in Fig. 14.
001aaa613
VCC
RESET
nRD
CEXT REXT
nA
nB
VCC
nCEXTGND nREXT/CEXT
nQ
nQ
123 13 (5)
4 (12)
15 (7)14 (6)8
1 (9)
2 (10)
3 (11)
Fig. 14. Power-up output pulse elimination circuit
74HC_HCT123 All information provided in this document is subject to legal disclaimers. © Nexperia B.V. 2020. All rights reserved
Product data sheet Rev. 11.1 — 3 September 2020 13 / 21
Nexperia 74HC123; 74HCT123
Dual retriggerable monostable multivibrator with reset
11.3. Power-down considerations
A large capacitor CEXT may cause problems when powering-down the monostable due to the
energy stored in this capacitor. When a system containing this device is powered-down or a
rapid decrease of VCC to zero occurs, the monostable may sustain damage, due to the capacitor
discharging through the input protection diodes. To avoid this possibility, use a damping diode
(DEXT) preferably a germanium or Schottky type diode able to withstand large current surges and
connect as shown in Fig. 15.
001aaa614
DEXT
nRD
CEXT REXT
nA
nB
VCC
nCEXT nREXT/CEXT
nQ
nQ
123 13 (5)
4 (12)
15 (7)
1 (9)
2 (10)
3 (11)
GND
14 (6)8
Fig. 15. Power-down protection circuit
74HC_HCT123 All information provided in this document is subject to legal disclaimers. © Nexperia B.V. 2020. All rights reserved
Product data sheet Rev. 11.1 — 3 September 2020 14 / 21
Nexperia 74HC123; 74HCT123
Dual retriggerable monostable multivibrator with reset
12. Package outline
X
w M
θ
A
A
1
A
2
b
p
D
H
E
L
p
Q
detail X
E
Z
e
c
L
v M A
(A )
3
A
8
9
1
16
y
pin 1 index
UNIT A
max. A
1 A
2 A
3 b
p c D
(1) E
(1) (1)
e H
E L L
p Q Z y w v θ
REFERENCES
OUTLINE
VERSION
EUROPEAN
PROJECTION ISSUE DATE
IEC JEDEC JEITA
mm
inches
1.75 0.25
0.10
1.45
1.25 0.25 0.49
0.36
0.25
0.19
10.0
9.8
4.0
3.8 1.27 6.2
5.8
0.7
0.6
0.7
0.3 8
0
o
o
0.25 0.1
DIMENSIONS (inch dimensions are derived from the original mm dimensions)
Note
1. Plastic or metal protrusions of 0.15 mm (0.006 inch) maximum per side are not included.
1.0
0.4
SOT109-1 99-12-27
03-02-19
076E07 MS-012
0.069 0.010
0.004
0.057
0.049 0.01 0.019
0.014
0.0100
0.0075
0.39
0.38
0.16
0.15 0.05
1.05
0.041
0.244
0.228
0.028
0.020
0.028
0.012
0.01
0.25
0.01 0.004
0.039
0.016
0 2.5 5 mm
scale
SO16: plastic small outline package; 16 leads; body width 3.9 mm SOT109-1
Fig. 16. Package outline SOT109-1 (SO16)
74HC_HCT123 All information provided in this document is subject to legal disclaimers. © Nexperia B.V. 2020. All rights reserved
Product data sheet Rev. 11.1 — 3 September 2020 15 / 21
Nexperia 74HC123; 74HCT123
Dual retriggerable monostable multivibrator with reset
UNIT A
1 A
2 A
3 b
p c D
(1) E
(1) e H
E L L
p Q Z y w v θ
REFERENCES
OUTLINE
VERSION
EUROPEAN
PROJECTION ISSUE DATE
IEC JEDEC JEITA
mm 0.21
0.05
1.80
1.65 0.25 0.38
0.25
0.20
0.09
6.4
6.0
5.4
5.2 0.65 1.25
7.9
7.6
1.03
0.63
0.9
0.7
1.00
0.55
8
0
o
o
0.13 0.2 0.1
DIMENSIONS (mm are the original dimensions)
Note
1. Plastic or metal protrusions of 0.25 mm maximum per side are not included.
SOT338-1 99-12-27
03-02-19
(1)
w M
b
p
D
H
E
E
Z
e
c
v M A
X
A
y
1 8
16 9
θ
A
A
1
A
2
L
p
Q
detail X
L
(A )
3
MO-150
pin 1 index
0 2.5 5 mm
scale
SSOP16: plastic shrink small outline package; 16 leads; body width 5.3 mm SOT338-1
A
max.
2
Fig. 17. Package outline SOT338-1 (SSOP16)
74HC_HCT123 All information provided in this document is subject to legal disclaimers. © Nexperia B.V. 2020. All rights reserved
Product data sheet Rev. 11.1 — 3 September 2020 16 / 21
Nexperia 74HC123; 74HCT123
Dual retriggerable monostable multivibrator with reset
UNIT A
1 A
2 A
3 b
p c D
(1) E (2) (1)
e H
E L L
p Q Z y w v θ
REFERENCES
OUTLINE
VERSION
EUROPEAN
PROJECTION ISSUE DATE
IEC JEDEC JEITA
mm 0.15
0.05
0.95
0.80
0.30
0.19
0.2
0.1
5.1
4.9
4.5
4.3 0.65 6.6
6.2
0.4
0.3
0.40
0.06
8
0
o
o
0.13 0.1 0.2 1
DIMENSIONS (mm are the original dimensions)
Notes
1. Plastic or metal protrusions of 0.15 mm maximum per side are not included.
2. Plastic interlead protrusions of 0.25 mm maximum per side are not included.
0.75
0.50
SOT403-1 MO-153 99-12-27
03-02-18
w M
b
p
D
Z
e
0.25
1 8
16 9
θ
A
A
1
A
2
L
p
Q
detail X
L
(A )
3
H
E
E
c
v M A
X
A
y
0 2.5 5 mm
scale
TSSOP16: plastic thin shrink small outline package; 16 leads; body width 4.4 mm SOT403-1
A
max.
1.1
pin 1 index
Fig. 18. Package outline SOT403-1 (TSSOP16)
74HC_HCT123 All information provided in this document is subject to legal disclaimers. © Nexperia B.V. 2020. All rights reserved
Product data sheet Rev. 11.1 — 3 September 2020 17 / 21
Nexperia 74HC123; 74HCT123
Dual retriggerable monostable multivibrator with reset
terminal 1
index area
0.5 1
A1 Eh
b
UNIT y e
0.2
c
REFERENCES
OUTLINE