INTEGRATED CIRCUITS
74LV423
Dual retriggerable monostable
multivibrator with reset
Product specification
IC24 Data Handbook
1997 Feb 04
Philips
Semiconductors
Philips Semiconductors
Preliminary specification
Dual retriggerable monostable multivibrator
with reset
74LV423
FEATURES
•
Optimized for Low Voltage applications: 1.0 to 5.5V
•
Accepts TTL input levels between V
CC
= 2.7V and V
CC
= 3.6V
•
Typical V
OLP
(output ground bounce)
t
0.8V @ V
CC
= 3.3V,
•
Typical V
OHV
(output V
OH
undershoot)
u
2V @ V
CC
= 3.3V,
•
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
•
Output capability: standard (except for nR
EXT
/C
EXT
)
•
I
CC
category: MSI
T
amb
= 25°C
T
amb
= 25°C
DESCRIPTION
The 74LV423 is a low-voltage Si-gate CMOS device and is pin and
function compatible with the 74HC/HCT423.
The 74LV423 is a dual retriggerable monostable multivibrator with
output pulse width control by three methods. The basic pulse time is
programmed by selection of an external resistor (R
EXT
) and
capacitor (C
EXT
). They are normally connected as shown in
Figure 1. 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 nR
D
, which
also inhibits the triggering. Figures 2 and 3 illustrate pulse control by
retriggering and early reset. The basic output pulse width is
essentially determined by the values of the external timing
components R
EXT
and C
EXT
. For pulse width when C
EXT
<10000pF,
see Figure 6. When C
EXT
u
10,000pF, the typical output pulse
width is defined as: t
W
= 0.45
R
EXT
C
EXT
(typ.), where
t
W
= pulse width in ns; R
EXT
= external resistor in KΩ; and
C
EXT
= external capacitor in pF. Schmitt-trigger action in the nA and
nB inputs makes the circuit highly tolerant of slower input rise and
fall times.
QUICK REFERENCE DATA
GND = 0V; T
amb
= 25°C; t
r
= t
f
v2.5
ns
SYMBOL
PARAMETER
Propagation delay
nA, nB to nQ, nQ
nR
D
to nQ, nQ
Input capacitance
Power dissipation capacitance per flip-flop
V
CC
= 3.3V, V
I
= GND to V
CC1
CONDITIONS
C
L
= 15pF
V
CC
= 3.3V
R
EXT
= 5KΩ
C
EXT
= 0pF
TYPICAL
UNIT
t
PHL
/t
PLH
C
I
C
PD
16
13
3.5
17
ns
ns
pF
pF
NOTES:
1. C
PD
is used to determine the dynamic power dissipation (P
D
in
µW)
V
CC2
f
i
)S
(C
L
V
CC2
f
o
) where:
P
D
= C
PD
f
i
= input frequency in MHz; C
L
= output load capacity in pF;
f
o
= output frequency in MHz; V
CC
= supply voltage in V;
V
CC2
f
o
) = sum of the outputs.
S
(C
L
ORDERING INFORMATION
PACKAGES
16-Pin Plastic DIL
16-Pin Plastic SO
16-Pin Plastic SSOP Type II
16-Pin Plastic TSSOP Type I
TEMPERATURE RANGE
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
OUTSIDE NORTH AMERICA
74LV423 N
74LV423 D
74LV423 DB
74LV423 PW
NORTH AMERICA
74LV423 N
74LV423 D
74LV423 DB
74LV423PW DH
PKG. DWG. #
SOT38-1
SOT109-1
SOT338-1
SOT403-1
1997 Feb 04
2
853–1913 17724
Philips Semiconductors
Preliminary specification
Dual retriggerable monostable multivibrator
with reset
74LV423
PIN CONFIGURATION
1A
1B
1R
D
1Q
2Q
2C
EXT
2R
EXT
/C
EXT
GND
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
V
CC
1R
EXT
/C
EXT
1C
EXT
1Q
2Q
2R
D
2B
2A
LOGIC SYMBOL
1C
EXT
2C
EXT
1R
EXT
/C
EXT
2R
EXT
/C
EXT
14
6
15
7
S
1Q
Q
1
9
1A
2A
1B
2B
T
Q
1Q
2Q
2Q
13
5
SV00096
2
10
4
12
PIN DESCRIPTION
PIN
NUMBER
1,9
2,10
3,11
4, 12
7
8
13, 5
14, 6
15
16
SYMBOL
1A, 2A
1B, 2B
1R
D
, 2R
D
1Q, 2Q
2R
EXT
/C
EXT
GND
1Q, 2Q
1C
EXT,
2C
EXT
1R
EXT
/C
EXT
V
CC
FUNCTION
3
1R
D
2R
D
R
D
Trigger inputs
(negative-edge triggered)
Trigger inputs
(positive-edge triggered)
Direct reset LOW
Outputs (active LOW)
External resistor/capacitor connection
11
SV00160
FUNCTIONAL DIAGRAM
1C
EXT
14
6
15
7
Ground (0V)
Outputs (active HIGH)
External capacitor connection
External resistor/capacitor connection
Positive supply voltage
S
2C
EXT
1R
EXT
/C
EXT
2R
EXT
/C
EXT
1Q
Q
2Q
13
5
LOGIC SYMBOL (IEEE/IEC)
14
15
1
2
4
3
CX
RCX
13
&
1
9
2
10
1A
2A
1B
2B
R
D
T
Q
1Q
2Q
4
12
3
11
1R
D
2R
D
R
SV00162
6
7
9
10
12
11
CX
RCX
5
&
R
SV00161
1997 Feb 04
3
Philips Semiconductors
Preliminary specification
Dual retriggerable monostable multivibrator
with reset
74LV423
LOGIC DIAGRAM
nR
EXT
/C
EXT
V
CC
R
D
Q
Q
R
R
CL V
CC
CL
V
CC
R
CL
CL
A
CL
B
It is recommended that Pin 6 (2C
EXT
) and Pin 14 (1C
EXT
) by externally grounded to Pin 8 (GND)
SV00163
FUNCTION TABLE
INPUTS
nR
D
L
X
X
H
H
nA
X
H
X
L
↓
nB
X
X
L
↑
H
C
EXT
OUTPUTS
nQ
L
L*
L*
nQ
H
H*
H*
R
EXT
V
CC
NOTES:
* If the monostable was triggered before this condition was
established, the pulse will continue as programmed.
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
to nC
EXT
(pin 14 or 6)
to nR
EXT
/C
EXT
(pin 15 or 7)
SV00101
Figure 1. Timing Component Connection
1997 Feb 04
4
Philips Semiconductors
Preliminary specification
Dual retriggerable monostable multivibrator
with reset
ABSOLUTE MAXIMUM RATINGS
1, 2
In accordance with the Absolute Maximum Rating System (IEC 134).
Voltages are referenced to GND (ground = 0V).
SYMBOL
V
CC
"I
IK
"I
OK
"I
O
PARAMETER
DC supply voltage
DC input diode current
DC output diode current
DC output source or sink current
– standard outputs
– bus driver outputs
DC V
CC
or GND current for types with
– standard outputs
– bus driver outputs
Storage temperature range
Power dissipation per package
– plastic DIL
– plastic mini-pack (SO)
– plastic shrink mini-pack (SSOP and TSSOP)
for temperature range: –40 to +125°C
above +70°C derate linearly with 12 mW/K
above +70°C derate linearly with 8 mW/K
above +60°C derate linearly with 5.5 mW/K
V
I
< –0.5 or V
I
> V
CC
+ 0.5V
V
O
< –0.5 or V
O
> V
CC
+ 0.5V
–0.5V < V
O
< V
CC
+ 0.5V
CONDITIONS
74LV423
RATING
–0.5 to +7.0
20
50
25
35
50
70
–65 to +150
750
500
500
UNIT
V
mA
mA
mA
"I
GND
,
"I
CC
T
stg
mA
°C
P
TOT
mW
NOTES:
1. Stresses beyond those listed may cause permanent damage to the device. These are stress ratings only and functional operation of the
device at these or any other conditions beyond those indicated under “recommended operating conditions” is not implied. Exposure to
absolute-maximum-rated conditions for extended periods may affect device reliability.
2. The input and output voltage ratings may be exceeded if the input and output current ratings are observed.
RECOMMENDED OPERATING CONDITIONS
SYMBOL
V
CC
V
I
V
O
T
amb
PARAMETER
DC supply voltage
Input voltage
Output voltage
Operating ambient temperature range in free
air
Input rise and fall times except for
Schmitt-trigger inputs
See DC and AC
characteristics per device
V
CC
= 1.0V to 2.0V
V
CC
= 2.0V to 2.7V
V
CC
= 2.7V to 3.6V
V
CC
= 3.6V to 5.5V
CONDITIONS
See Note 1
MIN
1.2
0
0
–40
–40
–
–
–
–
–
–
–
TYP
3.3
–
–
MAX
5.5
V
CC
V
CC
+85
+125
500
200
100
50
UNIT
V
V
V
°C
t
r
, t
f
ns/V
NOTE:
1. The LV is guaranteed to function down to V
CC
= 1.0V (input levels GND or V
CC
); DC characteristics are guaranteed from V
CC
= 1.2V to V
CC
= 5.5V.
1997 Feb 04
5
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