HD74LV123A
Dual Retriggerable Monostable Multivibrators
ADE-205-258A (Z)
2nd Edition
June 1999
Description
The HD74LV123A features output pulse-duration control by three methods. In the first method, the A
input is low and the B input goes high. In the second method, the B input is high and the
A input goes low.
In the third method, the
A input is low, the B input is high, and the clear (CLR) input goes high.
The basic pulse duration is programmed by selecting external resistance and capacitance values.
The external timing capacitor must be connected between Cext and Rext/Cext (positive) and an external
resistor connected between Rext/Cext and Vcc
To obtain variable pulse durations, connect an external variable resistance between Rext/Cext and Vcc.
Once triggered, the basic pulse duration can be extended by retriggering the gated low-level-active (
A) or
high-level-active (B) input. Pulse duration can be reduced by taking
CLR low.
Features
·
V
CC
= 2.0 V to 5.5 V operation
·
All inputs V
IH
(Max.) = 5.5 V (@V
CC
= 0 V to 5.5 V)
·
All outputs V
O
(Max.) = 5.5 V (@V
CC
= 0 V)
·
Output current
±
6 mA (@V
CC
= 3.0 V to 3.6 V),
±
12 mA (@V
CC
= 4.5 V to 5.5 V)
HD74LV123A
2
Function Table
Inputs
Outputs
CLR
A
B
Q
Q
L
X
X
L
H
H
H
X
L
H
H
X
L
L
H
H
L
H
H
L
H
Note:
H:
High level
L:
Low level
X:
Immaterial
:
Low to high transition
:
High to low transition
:
High level pulse
:
Low level pulse
Pin Arrangement
V
CC
1Rext / Cext
1Cext
1Q
2B
2
Q
2
CLR
1
A
1B
1
CLR
1
Q
2Q
2Cext
2Rext / Cext
2
A
(Top view)
11
12
13
14
15
16
1
2
3
4
5
6
7
GND 8
9
10
HD74LV123A
3
Absolute Maximum Ratings
Item
Symbol
Ratings
Unit
Conditions
Supply voltage range
V
CC
0.5 to 7.0
V
Input voltage range*
1
V
I
0.5 to 7.0
V
Output voltage range*
1, 2
V
O
0.5 to V
CC
+ 0.5
V
Output: H or L
0.5 to 7.0
V
CC
: OFF
Input clamp current
I
IK
20
mA
V
I
< 0
Output clamp current
I
OK
±
50
mA
V
O
< 0 or V
O
> V
CC
Continuous output current
I
O
±
25
mA
V
O
= 0 to V
CC
Continuous current through
V
CC
or GND
I
CC
or I
GND
±
50
mA
Maximum power dissipation
at Ta = 25
°
C (in still air)*
3
P
T
785
mW
SOP
500
TSSOP
Storage temperature
Tstg
65 to 150
°
C
Notes: The absolute maximum ratings are values which must not individually be exceeded, and furthermore,
no two of which may be realized at the same time.
1. The input and output voltage ratings may be exceeded if the input and output clamp-current
ratings are observed.
2. This value is limited to 5.5 V maximum.
3. The maximum package power dissipation was calculated using a junction temperature of 150
°
C.
HD74LV123A
4
Recommended Operating Conditions
Item
Symbol
Min
Typ
Max
Unit
Conditions
Supply voltage range
V
CC
2.0
--
5.5
V
Input voltage range
V
I
0
--
5.5
V
Output voltage range
V
O
0
--
V
CC
V
Output current
I
OH
--
--
50
µ
A
V
CC
= 2.0 V
--
--
2
mA
V
CC
= 2.3 to 2.7 V
--
--
6
V
CC
= 3.0 to 3.6 V
--
--
12
V
CC
= 4.5 to 5.5 V
I
OL
--
--
50
µ
A
V
CC
= 2.0 V
--
--
2
mA
V
CC
= 2.3 to 2.7 V
--
--
6
V
CC
= 3.0 to 3.6 V
--
--
12
V
CC
= 4.5 to 5.5 V
Input transition rise or fall rate
t /
v
0
--
200
ns/V
V
CC
= 2.3 to 2.7 V
0
--
100
V
CC
= 3.0 to 3.6 V
0
--
20
V
CC
= 4.5 to 5.5 V
External timing registance
Rext
5
--
--
k
V
CC
= 2.0 V
1
--
--
V
CC
3.0 V
External timing capacitance
Cext
--
Unlimited
--
F
Operating free-air temperature
Ta
40
85
°
C
Note:
Unused or floating inputs must be held high or low.
HD74LV123A
5
Logic Diagram
Q
Cext
Rext/
Cext
Q
Q
Q
A
B
CLR
CLR
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