74HC123; 74HCT123
Dual retriggerable monostable multivibrator with reset
Rev. 04 — 16 June 2006
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 time 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 the function table.
Schmitt-trigger action in the nA and nB inputs, makes the circuit highly tolerant to slower
input rise and fall times.
The 74HC123; 74HCT123 is identical to the 74HC423; 74HCT423 but can be triggered
via the reset input.
2. Features
I
I
I
I
I
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:
N
HBM EIA/JESD22-A114-C exceeds 2000 V
N
MM EIA/JESD22-A115-A exceeds 200 V
I
Specified from
−40 °C
to +85
°C
and from
−40 °C
to +125
°C
Philips Semiconductors
74HC123; 74HCT123
Dual retriggerable monostable multivibrator with reset
3. Ordering information
Table 1.
Ordering information
Package
Temperature range Name
74HC123
74HC123N
74HC123D
74HC123DB
74HC123PW
74HC123BQ
−40 °C
to +125
°C
−40 °C
to +125
°C
−40 °C
to +125
°C
−40 °C
to +125
°C
−40 °C
to +125
°C
DIP16
SO16
SSOP16
TSSOP16
DHVQFN16
plastic dual in-line package; 16 leads (300 mil);
long body
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
plastic dual in-line package; 16 leads (300 mil);
long body
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
SOT38-1
SOT109-1
SOT338-1
SOT403-1
SOT763-1
Description
Version
Type number
74HCT123
74HCT123N
74HCT123D
74HCT123DB
74HCT123PW
−40 °C
to +125
°C
−40 °C
to +125
°C
−40 °C
to +125
°C
−40 °C
to +125
°C
DIP16
SO16
SSOP16
TSSOP16
SOT38-1
SOT109-1
SOT338-1
SOT403-1
74HC_HCT123_4
© Koninklijke Philips Electronics N.V. 2006. All rights reserved.
Product data sheet
Rev. 04 — 16 June 2006
2 of 28
Philips Semiconductors
74HC123; 74HCT123
Dual retriggerable monostable multivibrator with reset
4. Functional diagram
1CEXT 14
1REXT/CEXT 15
S
1 1A
T
2 1B
Q
RD
1Q 4
Q
1Q 13
3 1RD
2CEXT
2REXT/CEXT
S
9 2A
T
10 2B
Q
RD
2Q 12
Q
6
7
2Q 5
11 2RD
001aaa610
Fig 1. Functional diagram
14
15
1CEXT 14
2CEXT
6
1
2
CX
RCX
&
4
13
1REXT/CEXT 15
2REXT/CEXT
S
1 1A
9 2A
2 1B
10 2B
3 1RD
11 2RD
T
Q
RD
1Q
4
9
10
mna515
7
3
R
Q
1Q 13
2Q 5
6
7
CX
RCX
&
12
5
2Q 12
11
R
mna516
Fig 2. Logic symbol
Fig 3. IEC logic symbol
74HC_HCT123_4
© Koninklijke Philips Electronics N.V. 2006. All rights reserved.
Product data sheet
Rev. 04 — 16 June 2006
3 of 28
Philips Semiconductors
74HC123; 74HCT123
Dual retriggerable monostable multivibrator with reset
REXT/CEXT
V
CC
RD
R
CL
R
CL
Q
Q
V
CC
V
CC
R
CL
mna518
A
CL
CL
B
R
Fig 4. Logic diagram
74HC_HCT123_4
© Koninklijke Philips Electronics N.V. 2006. All rights reserved.
Product data sheet
Rev. 04 — 16 June 2006
4 of 28
Philips Semiconductors
74HC123; 74HCT123
Dual retriggerable monostable multivibrator with reset
5. Pinning information
5.1 Pinning
74HC123BQ
terminal 1
index area
1B
16 V
CC
15 1REXT/CEXT
14 1CEXT
13 1Q
12 2Q
11 2RD
10 2B
9
001aaa698
74HC123
74HCT123
1A
1B
1RD
1Q
2Q
2CEXT
2REXT/CEXT
GND
1
2
3
4
5
6
7
8
2
3
4
5
6
7
8
GND
2A
9
GND
(1)
16 V
CC
15 1REXT/CEXT
14 1CEXT
13 1Q
12 2Q
11 2RD
10 2B
1RD
1Q
2Q
2CEXT
2REXT/CEXT
1
1A
2A
001aaf046
Transparent top view
(1) The die substrate is attached to this
pad using conductive die attach
material. It can not be used as supply
pin or input.
Fig 5. Pin configuration for DIP16, 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
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
74HC_HCT123_4
© Koninklijke Philips Electronics N.V. 2006. All rights reserved.
Product data sheet
Rev. 04 — 16 June 2006
5 of 28