Datasheet 74 hct423 DATASHEETS (Philips)

INTEGRATED CIRCUITS

DATA SH EET

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

74HC/HCT423

Dual retriggerable monostable
multivibrator with reset

Product specification
Supersedes data of December 1990
File under Integrated Circuits, IC06

1998 Jul 08

Philips Semiconductors Product specification

Dual retriggerable monostable
multivibrator with reset

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 nR

EXT/CEXT

• ICC category: MSI

GENERAL DESCRIPTION

The 74HC/HCT423 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/HCT423 are dual retriggerable monostable
multivibrators with output pulse width control by two
methods. The basic pulse time is programmed by
selection of an external resistor (R

) and capacitor

EXT

QUICK REFERENCE DATA

GND = 0 V; T

= 25 °C; tr= tf= 6 ns

amb

)

74HC/HCT423

(C

). The external resistor and capacitor are normally

EXT

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.
When nRDis LOW, it forces the nQ output LOW, the
nQ output HIGH and also inhibits the triggering.

Figures 7 and 8 illustrate pulse control by reset. The basic
output pulse width is essentially determined by the values
of the external timing components R
For pulse widths, when C
When C

> 10 000 pF, the typical output pulse width is

EXT

< 10 000 pF, see Fig.9.

EXT

defined as:
tW= 0.45 × R

EXT

× C

EXT

(typ.),

where, tW= pulse width in ns;

R

= external resistor in kΩ;

EXT

C

= external capacitor in pF.

EXT

Schmitt-trigger action in the nA and nB inputs, makes the
circuit highly tolerant to slower input rise and fall times.

The “423” is identical to the “123” but cannot be triggered
via the reset input.

EXT

and C

EXT

.

SYMBOL PARAMETER CONDITIONS

t

/ t

PHL

PLH

C

I

t

W

propagation delay CL= 15 pF; VCC= 5 V;

R

=5 kΩ; C

n

A, nB to nQ, nQ2526ns

n

R

to nQ, nQ2022ns

D

EXT

input capacitance 3.5 3.5 pF
minimum output pulse width nQ, nQ notes 1 and 2 75 75 ns

Notes

1. C

is used to determine the dynamic power dissipation (PDin µW):

PD

PD= CPD× V

2

× fi+∑(CL× V

CC

2

× fo) + 0.75 × C

CC

EXT

× V

CC

2

fi= input frequency in MHz
fo= output frequency in MHz
D = duty factor in %
∑ (CL× V

2

× fo) = sum of outputs

CC

CL= output load capacitance in pF
VCC= supply voltage in V
C

= timing capacitance in pF

EXT

2. For HC the condition is VI= GND to V

CC

For HCT the condition is VI= GND to VCC− 1.5 V

TYPICAL

HC HCT

= 0 pF

EXT

× fo+ D × 16 × VCCwhere:

UNIT

1998 Jul 08 2

Philips Semiconductors Product specification

Dual retriggerable monostable
multivibrator with reset

ORDERING INFORMATION

TYPE

NUMBER

74HC423N;
74HCT423N

74HC423D;
74HCT423D

PIN DESCRIPTION

PIN NO. SYMBOL NAME AND FUNCTION

1, 9 1
2, 10 1B, 2B trigger inputs (positive-edge triggered)
3, 11 1
4, 12 1
72R
8 GND ground (0 V)
13, 5 1Q, 2Q outputs (active HIGH)
14, 6 1C
15 1R
16 V

NAME DESCRIPTION VERSION

DIP16 plastic dual in-line package; 16 leads (300 mil); long body SOT38-1

SO16 plastic small outline package; 16 leads; body width 3.9 mm;

low stand-off height

A, 2A trigger inputs (negative-edge triggered)

RD,2R

D

Q, 2Q outputs (active LOW)

EXT/CEXT

,2C

EXT
EXT/CEXT

CC

EXT

direct reset action (active LOW)

external resistor/capacitor connection

external capacitor connection
external resistor/capacitor connection
positive supply voltage

PACKAGE

74HC/HCT423

SOT109-1

Fig.1 Pin configuration. Fig.2 Fig.3 IEC logic symbol.

1998 Jul 08 3

Philips Semiconductors Product specification

Dual retriggerable monostable
multivibrator with reset

74HC/HCT423

FUNCTION TABLE

n

R

D

LXX L H
XHXL
XXLL
HL↑
H↓H

Notes

1. 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.4 Functional diagram.

INPUTS OUTPUTS

nAnB nQ nQ

(2)
(2)

(2)

H

(2)

H

2. If the monostable was triggered before this condition was established, the pulse will continue as programmed.

1998 Jul 08 4

Philips Semiconductors Product specification

Dual retriggerable monostable
multivibrator with reset

74HC/HCT423

It is recommended to ground pins 6 (2C

) externally to pin 8 (GND).

(1C

EXT

) and 14

EXT

Fig.5 Logic diagram.

Fig.6 Timing component connections.

1998 Jul 08 5

Philips Semiconductors Product specification

Dual retriggerable monostable
multivibrator with reset

DC CHARACTERISTICS FOR 74HC

For the DC characteristics see
Output capability: standard (except for nR

ICC category: MSI

AC CHARACTERISTICS FOR 74HC

GND = 0 V; t

= tf= 6 ns; CL= 50 pF

r

SYMBOL PARAMETER

t

PHL

/ t

propagation delay

PLH

nA, nB to nQ, nQ

t

PHL

/ t

propagation delay

PLH

nRDto nQ, nQ

t

THL

/ t

output transition time 19 75 95 110 ns 2.0

TLH

“74HC/HCT/HCU/HCMOS Logic Family Specifications”

min. typ. max min max min. max.

.

EXT/CEXT

)

(°C)

T

amb

74HC

UNIT

+25 −40 to +85 −40 to +125

80 255 320 385 ns 2.0 C
29 51 64 77 4.5
23 43 54 65 6.0
66 215 270 325 ns 2.0 C
24 43 54 65 4.5
19 37 46 55 6.0

7 15 19 22 4.5
6 13 16 19 6.0

74HC/HCT423

TEST CONDITIONS

V

WAVEFORMS/

CC

(V)

R

R

EXT
EXT

EXT
EXT

NOTES

= 0 pF;
=5 kΩ

= 0 pF;
=5 kΩ

t

W

trigger pulse width

nA = LOW

100 11 125 150 ns 2.0 Fig.7
20 4 25 30 4.5
17 3 21 26 6.0

t

W

trigger pulse width

nB = HIGH

100 17 125 150 ns 2.0 Fig.7
20 6 25 30 4.5
17 5 21 26 6.0

t

W

reset pulse width

nRD= LOW

100 14 125 150 ns 2.0 Fig.8
20 5 25 30 4.5
17 4 21 26 6.0

t

W

output pulse width

nQ = HIGH
nQ = LOW

t

W

output pulse width

nQ = HIGH
nQ = LOW

450 −− µs 5.0 C

75 −− ns 5.0 C

= 100 nF;

EXT

R

= 10 kΩ;

EXT

Figs 7 and 8

= 0 pF;

EXT

R

=5 kΩ;

EXT

note 1;
Figs 7 and 8

t

rt

retrigger time

nA, nB

110 −− ns 5.0 C

R

EXT
EXT

= 0 pF;
=5 kΩ;

note 2; Fig. 7

R

EXT

external timing resistor 10

2

C

EXT

external timing capacitor no limits pF 5.0 Fig.9; note 3

1000

−− kΩ2.0

1000

Fig.9

5.0

1998 Jul 08 6

Philips Semiconductors Product specification

Dual retriggerable monostable

74HC/HCT423

multivibrator with reset

DC CHARACTERISTICS FOR 74HCT

For the DC characteristics see
Output capability: standard (except for nR

ICCcategory: MSI

Note to HCT types

The value of additional quiescent supply current (∆I
To determine ∆ICCper input, multiply this value by the unit load coefficient shown in the table below.

INPUT UNIT LOAD COEFFICIENT

A, nB 0.35

n
n

R

D

0.50

AC CHARACTERISTICS FOR 74HCT

GND = 0 V; t

= tf= 6 ns; CL= 50 pF

r

SYMBOL PARAMETER

t

PHL

/ t

propagation delay

PLH

nA, nB to nQ, nQ

t

PHL

/ t

propagation delay

PLH

nRDto nQ, nQ

t

THL

/ t

output transition time 7 15 19 22 ns 4.5

TLH

“74HC/HCT/HCU/HCMOS Logic Family Specifications”

EXT/CEXT

)

) for a unit load of 1 is given in the family specifications.

CC

(°C)

T

amb

74HCT

+25 −40 to +85 −40 to +125

min. typ. max. min. max. min. max.

30 51 64 77 ns 4.5 C

26 48 60 72 ns 4.5 C

.

UNIT

TEST CONDITIONS

V

CC

(V)

WAVEFORMS/

NOTES

= 0 pF;

EXT

R

=5 kΩ

EXT

= 0 pF;

EXT

R

=5 kΩ

EXT

t

W

trigger pulse width

20 5 25 30 ns 4.5 Fig.7

nA = LOW

t

W

trigger pulse width

20 5 25 30 ns 4.5 Fig.7

nB = HIGH

t

W

reset pulse width

20 7 25 30 ns 4.5 Fig.8

nRD= LOW

t

W

output pulse width

450 −−µs 5.0 C
nQ = HIGH
nQ = LOW

t

W

output pulse width

75 −−ns 5.0 C
nQ = HIGH
nQ = LOW

t

rt

retrigger time

110 −−ns 5.0 C
nA, nB

R

EXT

C

EXT

external timing resistor 2 1000 −−kΩ5.0 Fig.9
external timing

no limits pF 5.0 Fig.9; note 3

capacitor

1998 Jul 08 7

= 100 nF;

EXT

R

= 10 kΩ;

EXT

Figs 7 and 8

= 0 pF;

EXT

R

=5 kΩ;

EXT

note 1; Figs 7 and
8

= 0 pF;

EXT

R

=5 kΩ;

EXT

note 2; Fig.7

Philips Semiconductors Product specification

Dual retriggerable monostable

74HC/HCT423

multivibrator with reset

Notes

1. For other R
If C

> 10 pF, the next formula is valid:

EXT

tW=K×R

where: t

R
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 (nR

2. The time to retrigger the monostable multivibrator depends on the values of R
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 C

> 10 pF, the next formula (at VCC= 5.0 V) for the set-up time of a retrigger pulse is valid:

EXT

where, t

C
R

The inherent test jig and pin capacitance at pins 15 and 7 (nR

3. When the device is powered-up, initiate the device via a reset pulse, when C

and C

EXT

= output pulse width in ns;

W

= external resistor in kΩ;C

EXT

trt=30+0.19 × R

= retrigger time in ns;

rt

= external capacitor in pF;

EXT

= external resistor in kΩ.

EXT

combinations see Fig.9.

EXT

× C

EXT

EXT

EXT

(typ.)

× C

EXT

0.9

+ 13 × R

= external capacitor in pF;

EXT

1.05

(typ.)

EXT

EXT/CEXT

EXT/CEXT

) is approximately 7 pF.

EXT

and C

EXT

.

) is 7 pF.

< 50 pF.

EXT

AC WAVEFORMS

Fig.7 Output pulse control using retrigger pulse; nRD= HIGH.

Fig.8 Output pulse control using reset input nRD; nA = LOW.

1998 Jul 08 8

Philips Semiconductors Product specification

Dual retriggerable monostable

74HC/HCT423

multivibrator with reset

Fig.9 Typical output pulse width as a function of the external capacitor values at VCC= 5.0 V and T

amb

=25°C.

Fig.10 Typical ‘K’ factor; external capacitance = 10 nF, external resistance = 10 kΩ to 100 kΩ and T

1998 Jul 08 9

amb

=25°C.

Philips Semiconductors Product specification

Dual retriggerable monostable

74HC/HCT423

multivibrator with reset

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 R
CX, this output pulse can be eliminated using the circuit shown in Fig.11.

X

and

Fig.11 Power-up output pulse elimination circuit.

Power-down considerations

A large capacitor (C
capacitor. When a system containing this device is powered-down or a rapid decrease of VCCto 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.

) may cause problems when powering-down the monostable due to the energy stored in this

X

Fig.12 Power-down protection circuit.

1998 Jul 08 10

Philips Semiconductors Product specification

Dual retriggerable monostable
multivibrator with reset

PACKAGE OUTLINES

DIP16: plastic dual in-line package; 16 leads (300 mil); long body

D

seating plane

L

Z

16

e

b

b

1

9

A

1

w M

74HC/HCT423

SOT38-1

M

E

A

2

A

c

(e )

1

M

H

pin 1 index

1

0 5 10 mm

DIMENSIONS (inch dimensions are derived from the original mm dimensions)

A

UNIT

mm

inches

Note

1. Plastic or metal protrusions of 0.25 mm maximum per side are not included.

A

max.

4.7 0.51 3.7

OUTLINE

VERSION

SOT38-1

min.

A

1 2

max.

0.15

IEC JEDEC EIAJ

050G09 MO-001AE

b

1.40

1.14

0.055

0.045

b

1

0.53

0.38

0.021

0.015

REFERENCES

cEe M

0.32

0.23

0.013

0.009

D

21.8

21.4

0.86

0.84

8

scale

(1) (1)

6.48

6.20

0.26

0.24

E

(1)

Z

e

0.30

1

0.15

0.13

M

L

3.9

3.4

E

8.25

7.80

0.32

0.31

EUROPEAN

PROJECTION

9.5

8.3

0.37

0.33

w

H

0.2542.54 7.62

0.010.100.0200.19

ISSUE DATE

92-10-02
95-01-19

max.

2.2

0.087

1998 Jul 08 11

Philips Semiconductors Product specification

Dual retriggerable monostable
multivibrator with reset

SO16: plastic small outline package; 16 leads; body width 3.9 mm

D

c

y

Z

16

9

74HC/HCT423

SOT109-1

E

H

E

A

X

v M

A

pin 1 index

1

e

0 2.5 5 mm

DIMENSIONS (inch dimensions are derived from the original mm dimensions)

mm

A

max.

1.75

0.069

A1A2A

0.25

1.45

0.10

1.25

0.010

0.057

0.004

0.049

0.25

0.01

b

3

p

0.49

0.25

0.36

0.19

0.0100

0.019

0.0075

0.014

UNIT

inches

Note

1. Plastic or metal protrusions of 0.15 mm maximum per side are not included.

(1)E(1) (1)

cD

10.0

9.8

0.39

0.38

8

b

p

scale

eHELLpQZywv θ

4.0

1.27

3.8

0.16

0.050

0.15

w M

6.2

5.8

0.244

0.228

A

2

1.05

0.041

Q

A

1

detail X

1.0

0.7

0.4

0.6

0.028

0.039

0.020

0.016

(A )

L

p

L

0.25 0.1

0.25

0.01

0.01 0.004

A

3

θ

0.7

0.3

0.028

0.012

o

8

o

0

OUTLINE

VERSION

SOT109-1

IEC JEDEC EIAJ

076E07S MS-012AC

REFERENCES

1998 Jul 08 12

EUROPEAN

PROJECTION

ISSUE DATE

95-01-23
97-05-22

Philips Semiconductors Product specification

Dual retriggerable monostable
multivibrator with reset

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

S

OLDERING 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 (T
printed-circuit board has been pre-heated, forced cooling
may be necessary immediately after soldering to keep the
temperature within the permissible limit.

R

EPAIRING 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

REFLOW SOLDERING
Reflow soldering techniques are suitable for all SO

packages.

stg max

). If the

74HC/HCT423

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.

AVE SOLDERING

W
Wave soldering techniques can be used for all SO

packages if the following conditions are 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.

• The package footprint must incorporate solder thieves at
the downstream end.

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.

R

EPAIRING SOLDERED JOINTS

Fix the component by first soldering two diagonally­opposite 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.

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.

1998 Jul 08 13

Philips Semiconductors Product specification

Dual retriggerable monostable

74HC/HCT423

multivibrator with reset

DEFINITIONS

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.

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.

1998 Jul 08 14