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SCLS393O − APRIL 1998 − REVISED OCTOBER 2005
D
D
D
D
D
D
D
2-V to 5.5-V V
Operation
D
D
D
D
D
I
Supports Partial-Power-Down Mode
CC
off
Operation
Max t of 11 ns at 5 V
pd
Retriggerable for Very Long Output Pulses,
up to 100% Duty Cycle
Typical V
<0.8 V at V
(Output Ground Bounce)
OLP
CC
= 3.3 V, T = 25°C
A
Overriding Clear Terminates Output Pulse
Glitch-Free Power-Up Reset on Outputs
Typical V
>2.3 V at V
(Output V
Undershoot)
OHV
CC
OH
= 3.3 V, T = 25°C
A
Support Mixed-Mode Voltage Operation on
All Ports
Latch-Up Performance Exceeds 100 mA Per
JESD 78, Class II
Schmitt-Trigger Circuitry on A, B, and CLR
Inputs for Slow Input Transition Rates
D
ESD Protection Exceeds JESD 22
− 2000-V Human-Body Model (A114-A)
− 200-V Machine Model (A115-A)
Edge Triggered From Active-High or
Active-Low Gated Logic Inputs
− 1000-V Charged-Device Model (C101)
SN74LV123A . . . RGY PACKAGE
(TOP VIEW)
SN54LV123A . . . FK PACKAGE
(TOP VIEW)
SN54LV123A . . . J OR W PACKAGE
SN74LV123A . . . D, DB, DGV, NS,
OR PW PACKAGE
(TOP VIEW)
1
16
1A
1B
V
CC
1
2
3
4
5
6
7
8
16
15
14
13
15
14
13
12
11
10
1B
1CLR
1Q
2
3
4
5
6
7
1R /C
1R /C
ext ext
ext ext
1C
1Q
2Q
3
2
1 20 19
18
ext
1CLR
1Q
1C
1Q
ext
1C
1Q
1CLR
1Q
4
5
6
7
8
ext
17
16
2Q
2Q
12 2Q
NC
NC
2C
2CLR
2B
ext
11
10
9
2C
2CLR
2B
ext
15 2Q
2Q
2R /C
ext ext
2R /C
ext ext
GND
14
9 10 11 12 13
2CLR
2C
ext
8
9
2A
NC − No internal connection
description/ordering information
The ’LV123A devices are dual retriggerable monostable multivibrators designed for 2-V to 5.5-V V
operation.
CC
These edge-triggered multivibrators feature 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 output pulse duration is programmable by selecting external resistance and capacitance values. The
external timing capacitor must be connected between C
and R /C
(positive) and an external resistor
ext
ext ext
connected between R /C
resistance between R /C and V . The output pulse duration also can be reduced by taking CLR low.
and V . To obtain variable pulse durations, connect an external variable
ext ext
CC
ext ext
CC
Pulse triggering occurs at a particular voltage level and is not directly related to the transition time of the input
pulse. The A, B, and CLR inputs have Schmitt triggers with sufficient hysteresis to handle slow input transition
rates with jitter-free triggering at the outputs.
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. The input/output timing diagram
illustrates pulse control by retriggering the inputs and early clearing.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
Copyright 2005, Texas Instruments Incorporated
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