DATA SH EET
Product specification
Supersedes data of September 1993
File under Integrated Circuits, IC06
1998 Jul 08
INTEGRATED CIRCUITS
74HC/HCT123
Dual retriggerable monostable
multivibrator with reset
For a complete data sheet, please also download:
•The IC06 74HC/HCT/HCU/HCMOS Logic Family Specifications
•The IC06 74HC/HCT/HCU/HCMOS Logic Package Information
•The IC06 74HC/HCT/HCU/HCMOS Logic Package Outlines
1998 Jul 08 2
Philips Semiconductors Product specification
Dual retriggerable monostable
multivibrator with reset 74HC/HCT123
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
•Output capability: standard (except
for nREXT/CEXT)
•ICC category: MSI
GENERAL DESCRIPTION
The 74HC/HCT123 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 74HC/HCT123 are dual
retriggerable monostable
multivibrators with output pulse width
control by three methods. The basic
pulse time is programmed by
selection of an external resistor
(REXT) and capacitor (CEXT). The
external resistor and capacitor are
normally connected as shown in
Fig.6.
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.
An internal connection from nRD to
the input gates makes it possible to
trigger the circuit by a positive-going
signal at input nRD as shown in the
function table. Figures 7 and 8
illustrate pulse control by retriggering
and early reset. The basic output
pulse width is essentially determined
by the values of the external timing
components REXT and CEXT. For
pulse widths, when CEXT <10 000 pF,
see Fig.9.
When CEXT > 10 000 pF, the typical
output pulse width is defined as:
tW= 0.45 ×REXT ×CEXT (typ.),
where:
tW= pulse width in ns;
REXT = external resistor in kΩ;
CEXT = external capacitor in pF.
Schmitt-trigger action in the nA and
nB inputs, makes the circuit highly
tolerant to slower input rise and fall
times.
The ‘123’ is identical to the ‘423’ but
can be triggered via the reset input.
QUICK REFERENCE DATA
GND = 0 V; Tamb =25°C; tr=t
f=6ns
Notes
1. CPD is used to determine the dynamic power dissipation (PD in µW):
PD=C
PD ×VCC2×fi+∑(CL×VCC2×fo) + 0.75 ×CEXT
×VCC2×fo+D×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
∑(CL×VCC2×fo) sum of outputs
2. For HC the condition is VI= GND to VCC
For HCT the condition is VI= GND to VCC −1.5 V
SYMBOL PARAMETER CONDITIONS TYPICAL UNIT
HC HCT
tPHL/ tPLH propagation delay CL=15pF;
V
CC =5V;
R
EXT =5kΩ;
C
EXT =0pF
n
A, nB to nQ, nQ2626ns
nRD to nQ, nQ 20 23 ns
CIinput capacitance 3.5 3.5 pF
CPD power dissipation
capacitance per
monostable notes 1 and 2 54 56 pF
1998 Jul 08 3
Philips Semiconductors Product specification
Dual retriggerable monostable
multivibrator with reset 74HC/HCT123
ORDERING INFORMATION
PIN DESCRIPTION
TYPE
NUMBER PACKAGE
NAME DESCRIPTION VERSION
74HC123N;
74HCT123N DIP16 plastic dual in-line package; 16 leads (300 mil); long body SOT38-1
74HC123D;
74HCT123D SO16 plastic small outline package; 16 leads; body width 3.9 mm SOT109-1
74HC123DB;
74HCT123DB SSOP16 plastic shrink small outline package; 16 leads; body width 5.3 mm SOT338-1
74HC123PW;
74HCT123PW TSSOP16 plastic thin shrink small outline package; 16 leads; body width 4.4 mm SOT403-1
PIN NO. SYMBOL NAME AND FUNCTION
1, 9 1A, 2A trigger inputs (negative-edge triggered)
2, 10 1B, 2B trigger inputs (positive-edge triggered)
3, 11 1RD, 2RDdirect reset LOW and trigger action at positive edge
4, 12 1Q, 2Q outputs (active LOW)
72R
EXT/CEXT external resistor/capacitor connection
8 GND ground (0 V)
13, 5 1Q, 2Q outputs (active HIGH)
14, 6 1CEXT, 2CEXT external capacitor connection
15 1REXT/CEXT external resistor/capacitor connection
16 VCC positive supply voltage
Fig.1 Pin configuration. Fig.2 Logic symbol. Fig.3 IEC logic symbol.
1998 Jul 08 4
Philips Semiconductors Product specification
Dual retriggerable monostable
multivibrator with reset 74HC/HCT123
Fig.4 Functional diagram.
FUNCTION TABLE
Note
1. If the monostable was triggered
before this condition was
established, the pulse will
continue as programmed.
INPUTS OUTPUTS
nRDnAnBnQ nQ
LXXL H
XHXL
(1) H(1)
XXL L
(1) H(1)
HL ↑
H↓H
↑LH
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
Fig.5 Logic diagram.
(1) For minimum noise generation,
it is recommended to ground pins 6 (2CEXT)
and 14 (1CEXT) externally to pin 8 (GND).
1998 Jul 08 5
Philips Semiconductors Product specification
Dual retriggerable monostable
multivibrator with reset 74HC/HCT123
DC CHARACTERISTICS FOR 74HC
For the DC characteristics see
“74HC/HCT/HCU/HCMOS Logic Family Specifications”
.
Output capability: standard (except for nREXT/CEXT)
ICC category: MSI
Fig.6 Timing component connections.
1998 Jul 08 6
Philips Semiconductors Product specification
Dual retriggerable monostable
multivibrator with reset 74HC/HCT123
AC CHARACTERISTICS FOR 74HC
GND = 0 V; tr=t
f= 6 ns; CL=50pF
SYMBOL PARAMETER
Tamb (°C)
UNIT
TEST CONDITIONS
74HC VCC
(V) WAVEFORMS/
NOTES
+25 −40 to +85 −40 to +125
min. typ. max. min. max. min. max.
tPLH propagation delay
nRD, nA, nB to nQ
83
30
24
255
51
43
320
64
54
385
77
65 ns 2.0
4.5
6.0
CEXT = 0 pF;
REXT =5kΩ
t
PLH propagation delay
nRD, nA, nB to nQ
83
30
24
255
51
43
320
64
54
385
77
65 ns 2.0
4.5
6.0
CEXT = 0 pF;
REXT =5kΩ
t
PHL propagation delay
nRD to nQ (reset)
66
24
19
215
43
37
270
54
46
325
65
55 ns 2.0
4.5
6.0
CEXT = 0 pF;
REXT =5kΩ
t
PLH propagation delay
nRD to nQ (reset)
66
24
19
215
43
37
270
54
46
325
65
55 ns 2.0
4.5
6.0
CEXT = 0 pF;
REXT =5kΩ
t
THL / tTLH output transition
time
19
7
6
75
15
13
95
19
16
110
22
19 ns 2.0
4.5
6.0
tWtrigger pulse width
nA = LOW
100
20
17
8
3
2
125
25
21
150
30
26 ns 2.0
4.5
6.0 Fig.7
tWtrigger pulse width
nB = HIGH
100
20
17
17
6
5
125
25
21
150
30
26 ns 2.0
4.5
6.0 Fig.7
tWreset pulse width
nRD= LOW
100
20
17
14
5
4
125
25
21
150
30
26 ns 2.0
4.5
6.0 Fig.8
tW
output pulse width
nQ = HIGH
nQ = LOW 450 −−µs 5.0 CEXT = 100 nF;
REXT =10kΩ;
Figs 7 and 8
tW
output pulse width
nQ = HIGH
nQ = LOW 75 −−ns 5.0 CEXT = 0 pF;
REXT =5kΩ;
note 1; Figs 7 and 8
trt retrigger time
nA, nB 110 −−ns 5.0 CEXT = 0 pF;
REXT =5kΩ;
note 2; Fig.7
REXT external timing
resistor 10
21000
1000 −−kΩ
2.0
5.0 Fig.9
CEXT external timing
capacitor no limits pF 5.0 Fig.9; note 3
1998 Jul 08 7
Philips Semiconductors Product specification
Dual retriggerable monostable
multivibrator with reset 74HC/HCT123
DC CHARACTERISTICS FOR 74HCT
For the DC characteristics see
“74HC/HCT/HCU/HCMOS Logic Family Specifications”
.
Output capability: standard (except for nREXT / CEXT)
ICC category: MSI
Note to HCT types
The value of additional quiescent supply current (∆ICC) for a unit load of 1 is given in the family specifications.
To determine ∆ICC per input, multiply this value by the unit load coefficient shown in the table below.
INPUT UNIT LOAD COEFFICIENT
nA, nB 0.35
nRD0.50
1998 Jul 08 8
Philips Semiconductors Product specification
Dual retriggerable monostable
multivibrator with reset 74HC/HCT123
AC CHARACTERISTICS FOR 74HCT
GND = 0 V; tr=t
f= 6 ns; CL=50pF
SYMBOL PARAMETER
Tamb (°C)
UNIT
TEST CONDITIONS
74HCT VCC
(V) WAVEFORMS/
NOTES
+25 −40 to +85 −40 to +125
min. typ. max. min. max. min. max.
tPHL propagation delay
nRD, nA, nB to nQ 30 51 64 77 ns 4.5 CEXT = 0 pF;
REXT =5kΩ
t
PLH propagation delay
nRD, nA, nB to nQ 28 51 64 77 ns 4.5 CEXT = 0 pF;
REXT =5kΩ
t
PHL propagation delay
nRD to nQ (reset) 27 46 58 69 ns 4.5 CEXT = 0 pF;
REXT =5kΩ
t
PLH propagation delay
nRD to nQ (reset) 23 46 58 69 ns 4.5 CEXT = 0 pF;
REXT =5kΩ
t
THL / tTLH output transition time 7 15 19 22 ns 4.5
tWtrigger pulse width
nA = LOW 20 3 25 30 ns 4.5 Fig.7
tWtrigger pulse width
nB = HIGH 20 5 25 30 ns 4.5 Fig.7
tWreset pulse width
nRD= LOW 20 7 25 30 ns 4.5 Fig.8
tW
output pulse width
nQ = HIGH
nQ = LOW 450 −− µs 5.0 CEXT = 100 nF;
REXT =10kΩ;
Figs 7 and 8
tW
output pulse width
nQ = HIGH
nQ = LOW 75 −− ns 5.0 CEXT = 0 pF;
REXT =5kΩ;
note 1; Figs 7 and 8
trt retrigger time
nA, nB 110 −− ns 5.0 CEXT = 0 pF;
REXT =5kΩ;
note 2; Fig.7
REXT external timing
resistor 2 1000 −− kΩ5.0 Fig.9
CEXT external timing
capacitor no limits pF 5.0 Fig.9; note 3
1998 Jul 08 9
Philips Semiconductors Product specification
Dual retriggerable monostable
multivibrator with reset 74HC/HCT123
Notes to AC characteristics
1. For other REXT and CEXT combinations see Fig.9.
If CEXT >10 nF, the next formula is valid:
tW=K×R
EXT ×CEXT (typ.)
where: tW= output pulse width in ns;
REXT = external resistor in kΩ; CEXT = external capacitor in pF;
K = constant = 0.55 for VCC = 5.0 V and 0.48 for VCC = 2.0 V.
The inherent test jig and pin capacitance at pins 15 and 7 (nREXT / CEXT) is approximately 7 pF.
2. 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 set-up time of a retrigger pulse is valid:
trt = 30 + 0.19 ×REXT ×CEXT0.9 +13×R
EXT1.05 (typ.)
where: trt = 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.
3. When the device is powered-up, initiate the device via a reset pulse, when CEXT <50 pF.
1998 Jul 08 10
Philips Semiconductors Product specification
Dual retriggerable monostable
multivibrator with reset 74HC/HCT123
AC WAVEFORMS
Fig.7 Output pulse control using retrigger pulse;
nRD= HIGH. Fig.8 Output pulse control using reset input in nRD;
nA = LOW.
Fig.9 Typical output pulse width as a function of the
external capacitor values at VCC = 5.0 V and
Tamb =25°C.
Fig.10 HCT typical “k” factor as a function of VCC;
CX= 10 nF; RX=10kΩ to 100 kΩ.
1998 Jul 08 11
Philips Semiconductors Product specification
Dual retriggerable monostable
multivibrator with reset 74HC/HCT123
APPLICATION INFORMATION
Power-up considerations
When the monostable is powered-up it may produce an
output pulse, with a pulse width defined by the values of RX
and CX, this output pulse can be eliminated using the
circuit shown in Fig.11.
Power-down considerations
A large capacitor (CX) 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 substain damage, due to the
capacitor discharging through the input protection diodes.
To avoid this possibility, use a damping diode (DX)
preferably a germanium or Schottky type diode able to
withstand large current surges and connect as shown in
Fig.12
Fig.11 Power-up output pulse elimination circuit.
Fig.12 Power-down protection circuit.
1998 Jul 08 12
Philips Semiconductors Product specification
Dual retriggerable monostable
multivibrator with reset 74HC/HCT123
PACKAGE OUTLINES
UNIT A
max. 1 2 b1cEe M
H
L
REFERENCES
OUTLINE
VERSION EUROPEAN
PROJECTION ISSUE DATE
IEC JEDEC EIAJ
mm
inches
DIMENSIONS (inch dimensions are derived from the original mm dimensions)
SOT38-1 92-10-02
95-01-19
A
min. A
max. bmax.
w
ME
e1
1.40
1.14
0.055
0.045
0.53
0.38 0.32
0.23 21.8
21.4
0.86
0.84
6.48
6.20
0.26
0.24
3.9
3.4
0.15
0.13
0.2542.54 7.62
0.30
8.25
7.80
0.32
0.31
9.5
8.3
0.37
0.33
2.2
0.087
4.7 0.51 3.7
0.15 0.021
0.015 0.013
0.009 0.010.100.0200.19
050G09 MO-001AE
MH
c
(e )
1
ME
A
L
seating plane
A1
wM
b1
e
D
A2
Z
16
1
9
8
b
E
pin 1 index
0 5 10 mm
scale
Note
1. Plastic or metal protrusions of 0.25 mm maximum per side are not included.
(1) (1)
D(1)
Z
DIP16: plastic dual in-line package; 16 leads (300 mil); long body SOT38-1
1998 Jul 08 13
Philips Semiconductors Product specification
Dual retriggerable monostable
multivibrator with reset 74HC/HCT123
X
wM
θ
A
A1
A2
bp
D
HE
Lp
Q
detail X
E
Z
e
c
L
vMA
(A )
3
A
8
9
1
16
y
pin 1 index
UNIT A
max. A1A2A3bpcD
(1) E(1) (1)
eH
ELL
pQZywv θ
REFERENCES
OUTLINE
VERSION EUROPEAN
PROJECTION ISSUE DATE
IEC JEDEC EIAJ
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 maximum per side are not included.
1.0
0.4
SOT109-1 95-01-23
97-05-22
076E07S MS-012AC
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 0.050
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
1998 Jul 08 14
Philips Semiconductors Product specification
Dual retriggerable monostable
multivibrator with reset 74HC/HCT123
UNIT A1A2A3bpcD
(1) E(1) eH
ELL
pQZywv θ
REFERENCES
OUTLINE
VERSION EUROPEAN
PROJECTION ISSUE DATE
IEC JEDEC EIAJ
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
0.130.2 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 94-01-14
95-02-04
(1)
wM
bp
D
HE
E
Z
e
c
vMA
X
A
y
18
16 9
θ
A
A1
A2
Lp
Q
detail X
L
(A )
3
MO-150AC
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.
2.0
1998 Jul 08 15
Philips Semiconductors Product specification
Dual retriggerable monostable
multivibrator with reset 74HC/HCT123
UNIT A1A2A3bpcD
(1) E(2) (1)
eH
ELL
pQZywv θ
REFERENCES
OUTLINE
VERSION EUROPEAN
PROJECTION ISSUE DATE
IEC JEDEC EIAJ
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 0.10.21.0
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 94-07-12
95-04-04
wM
bp
D
Z
e
0.25
18
16 9
θ
A
A1
A2
Lp
Q
detail X
L
(A )
3
HE
E
c
vMA
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.
1.10
pin 1 index
1998 Jul 08 16
Philips Semiconductors Product specification
Dual retriggerable monostable
multivibrator with reset 74HC/HCT123
SOLDERING
Introduction
There is no soldering method that is ideal for all IC
packages. Wave soldering is often preferred when
through-hole and surface mounted components are mixed
on one printed-circuit board. However, wave soldering is
not always suitable for surface mounted ICs, or for
printed-circuits with high population densities. In these
situations reflow soldering is often used.
This text gives a very brief insight to a complex technology.
A more in-depth account of soldering ICs can be found in
our
“Data Handbook IC26; Integrated Circuit Packages”
(order code 9398 652 90011).
DIP
SOLDERING BY DIPPING OR BY WAVE
The maximum permissible temperature of the solder is
260 °C; solder at this temperature must not be in contact
with the joint for more than 5 seconds. The total contact
time of successive solder waves must not exceed
5 seconds.
The device may be mounted up to the seating plane, but
the temperature of the plastic body must not exceed the
specified maximum storage temperature (Tstg max). If the
printed-circuit board has been pre-heated, forced cooling
may be necessary immediately after soldering to keep the
temperature within the permissible limit.
REPAIRING SOLDERED JOINTS
Apply a low voltage soldering iron (less than 24 V) to the
lead(s) of the package, below the seating plane or not
more than 2 mm above it. If the temperature of the
soldering iron bit is less than 300 °C it may remain in
contact for up to 10 seconds. If the bit temperature is
between 300 and 400 °C, contact may be up to 5 seconds.
SO, SSOP and TSSOP
REFLOW SOLDERING
Reflow soldering techniques are suitable for all SO, SSOP
and TSSOP packages.
Reflow soldering requires solder paste (a suspension of
fine solder particles, flux and binding agent) to be applied
to the printed-circuit board by screen printing, stencilling or
pressure-syringe dispensing before package placement.
Several techniques exist for reflowing; for example,
thermal conduction by heated belt. Dwell times vary
between 50 and 300 seconds depending on heating
method.
Typical reflow temperatures range from 215 to 250 °C.
Preheating is necessary to dry the paste and evaporate
the binding agent. Preheating duration: 45 minutes at
45 °C.
WAVE SOLDERING
Wave soldering can be used for all SO packages. Wave
soldering is not recommended for SSOP and TSSOP
packages, because of the likelihood of solder bridging due
to closely-spaced leads and the possibility of incomplete
solder penetration in multi-lead devices.
If wave soldering is used - and cannot be avoided for
SSOP and TSSOP packages - the following conditions
must be observed:
•A double-wave (a turbulent wave with high upward
pressure followed by a smooth laminar wave) soldering
technique should be used.
•The longitudinal axis of the package footprint must be
parallel to the solder flow and must incorporate solder
thieves at the downstream end.
Even with these conditions:
•Only consider wave soldering SSOP packages that
have a body width of 4.4 mm, that is
SSOP16 (SOT369-1) or SSOP20 (SOT266-1).
•Do not consider wave soldering TSSOP packages
with 48 leads or more, that is TSSOP48 (SOT362-1)
and TSSOP56 (SOT364-1).
During placement and before soldering, the package must
be fixed with a droplet of adhesive. The adhesive can be
applied by screen printing, pin transfer or syringe
dispensing. The package can be soldered after the
adhesive is cured.
Maximum permissible solder temperature is 260 °C, and
maximum duration of package immersion in solder is
10 seconds, if cooled to less than 150 °C within
6 seconds. Typical dwell time is 4 seconds at 250 °C.
A mildly-activated flux will eliminate the need for removal
of corrosive residues in most applications.
1998 Jul 08 17
Philips Semiconductors Product specification
Dual retriggerable monostable
multivibrator with reset 74HC/HCT123
REPAIRING SOLDERED JOINTS
Fix the component by first soldering two diagonally- opposite end leads. Use only a low voltage soldering iron (less
than 24 V) applied to the flat part of the lead. Contact time must be limited to 10 seconds at up to 300 °C. When using a
dedicated tool, all other leads can be soldered in one operation within 2 to 5 seconds between 270 and 320 °C.
DEFINITIONS
LIFE SUPPORT APPLICATIONS
These products are not designed for use in life support appliances, devices, or systems where malfunction of these
products can reasonably be expected to result in personal injury. Philips customers using or selling these products for
use in such applications do so at their own risk and agree to fully indemnify Philips for any damages resulting from such
improper use or sale.
Data sheet status
Objective specification This data sheet contains target or goal specifications for product development.
Preliminary specification This data sheet contains preliminary data; supplementary data may be published later.
Product specification This data sheet contains final product specifications.
Limiting values
Limiting values given are in accordance with the Absolute Maximum Rating System (IEC 134). Stress above one or
more of the limiting values may cause permanent damage to the device. These are stress ratings only and operation
of the device at these or at any other conditions above those given in the Characteristics sections of the specification
is not implied. Exposure to limiting values for extended periods may affect device reliability.
Application information
Where application information is given, it is advisory and does not form part of the specification.
