TI SN74LV123ADGV

SN54LV123A, SN74LV123A
DUAL RETRIGGERABLE MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SCLS393A – APRIL 1998 – REVISED DECEMBER 1999
D
D
D
D
D
D
D
description
SN54LV123A . . . J OR W PACKAGE
SN74LV123A . . . D, DB, DGV, NS, OR PW PACKAGE
(TOP VIEW)
1A
1B
1CLR
1Q
2Q
2Cext
2Rext/Cext
GND
16
2
15
3
14
4
13
5
12
6
11
7
10
8
9
VCC
1Rext/Cext
1Cext
1Q
2Q
2CLR
2B
2A
SN54LV123A . . . FK PACKAGE
(TOP VIEW)
1CLR
1Q
NC
2Q
2Cext
The ’LV123A devices are dual retriggerable
monostable multivibrators designed for 2-V to
5.5-V VCC operation.
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.
1
1B
1A
NC
VCC
1R ext /C ext
D
EPIC  (Enhanced-Performance Implanted
CMOS) Process
Schmitt-Trigger Circuitry on A, B, and CLR
Inputs for Slow Input Transition Rates
Edge Triggered From Active-High or
Active-Low Gated Logic Inputs
Retriggerable for Very Long Output Pulses,
up to 100% Duty Cycle
Overriding Clear Terminates Output Pulse
Glitch-Free Power-Up Reset on Outputs
Latch-Up Performance Exceeds 100 mA Per
JESD 78, Class II
ESD Protection Exceeds JESD 22
– 2000-V Human-Body Model (A114-A)
– 200-V Machine Model (A115-A)
– 1000-V Charged-Device Model (C101)
Package Options Include Plastic
Small-Outline (D, NS), Shrink Small-Outline
(DB), Thin Very Small-Outline (DGV), and
Thin Shrink Small-Outline (PW) Packages,
Ceramic Flat (W) Packages, Chip Carriers
(FK), and DIPs (J)
4
3 2 1 20 19
18
5
17
6
16
7
15
8
14
9 10 11 12 13
1Cext
1Q
NC
2Q
2CLR
2R ext /Cext
GND
NC
2A
2B
D
NC – No internal connection
The output pulse duration is programmable 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. The output pulse duration can also be reduced by taking CLR low.
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.
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.
EPIC is a trademark of Texas Instruments Incorporated.
Copyright  1999, Texas Instruments Incorporated
UNLESS OTHERWISE NOTED this document contains PRODUCTION
DATA information current as of publication date. Products conform to
specifications per the terms of Texas Instruments standard warranty.
Production processing does not necessarily include testing of all
parameters.
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1
SN54LV123A, SN74LV123A
DUAL RETRIGGERABLE MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SCLS393A – APRIL 1998 – REVISED DECEMBER 1999
description (continued)
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.
The variance in output pulse duration from device to device typically is less than ±0.5% for given external timing
components. An example of this distribution for the ’LV123A is shown in Figure 11. Variations in output pulse
width versus supply voltage and temperature are shown in Figure 7.
During power up, Q outputs will be in the high state, and Q outputs will be in the low state. The outputs will be
glitch free without applying a reset pulse.
Pin assignments for these devices are identical to those of the ’AHC123A and ’AHCT123A devices for
interchangeability when allowed.
The SN54LV123A is characterized for operation over the full military temperature range of –55°C to 125°C.
The SN74LV123A is characterized for operation from –40°C to 85°C.
For additional application information on multivibrators, see the application report Designing With The
SN74AHC123A and SN74AHCT123A, literature number SCLA014.
FUNCTION TABLE
(each multivibrator)
INPUTS
OUTPUTS
CLR
A
B
Q
L
X
X
X
H
X
L
L†
X
X
L
L†
H
L
↑
H
#
H
Q
H
H†
H†
↑
L
H
† These outputs are based on the
assumption that the indicated steady-state
conditions at the A and B inputs have been
set up long enough to complete any pulse
started before the setup.
2
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SN54LV123A, SN74LV123A
DUAL RETRIGGERABLE MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SCLS393A – APRIL 1998 – REVISED DECEMBER 1999
logic symbol†
1A
1B
1
&
2
13
1CLR
3
14
1Cext
15
1Rext/Cext
2A
2B
R
1Q
CX
RX/CX
9
&
10
5
11
2CLR
2Cext
2Rext/Cext
1Q
4
6
7
12
R
2Q
2Q
CX
RX/CX
† This symbol is in accordance with ANSI/IEEE Std 91-1984 and IEC Publication 617-12.
Pin numbers shown are for the D, DB, J, N, PW, and W packages.
logic diagram, each multivibrator (positive logic)
Rext/Cext
A
Cext
B
Q
CLR
R
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Q
3
SN54LV123A, SN74LV123A
DUAL RETRIGGERABLE MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SCLS393A – APRIL 1998 – REVISED DECEMBER 1999
input/output timing diagram
trr
A
B
CLR
Rext/Cext
Q
Q
tw
tw
tw + trr
absolute maximum ratings over operating free-air temperature (unless otherwise noted)†
Supply voltage range, VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.5 V to 7 V
Input voltage range, VI (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.5 V to 7 V
Output voltage range in high or low state, VO (see Notes 1 and 2) . . . . . . . . . . . . . . . . . –0.5 V to VCC + 0.5 V
Output voltage range in power-off state, VO (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.5 V to 7 V
Input clamp current, IIK (VI < 0) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –20 mA
Output clamp current, IOK (VO < 0 or VO > VCC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±50 mA
Continuous output current, IO (VO = 0 to VCC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±25 mA
Continuous current through VCC or GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±50 mA
Package thermal impedance, θJA (see Note 3): D package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113°C/W
DB package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131°C/W
DGV package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180°C/W
NS package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111°C/W
PW package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149°C/W
Storage temperature range, Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –65°C to 150°C
† Stresses beyond those listed under “absolute maximum ratings” 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.
NOTES: 1. The input and output voltage ratings may be exceeded if the input and output current ratings are observed.
2. This value is limited to 7 V maximum.
3. The package thermal impedance is calculated in accordance with JESD 51.
4
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SN54LV123A, SN74LV123A
DUAL RETRIGGERABLE MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SCLS393A – APRIL 1998 – REVISED DECEMBER 1999
recommended operating conditions (see Note 4)
SN54LV123A
VCC
VIH
Supply voltage
High level input voltage
High-level
VCC = 2 V
VCC = 2.3 V to 2.7 V
VCC = 3 V to 3.6 V
VCC = 4.5 V to 5.5 V
MAX
2
5.5
VCC × 0.7
VCC × 0.7
VCC = 2 V
VCC = 2.3 V to 2.7 V
0
Output voltage
0
Rextt
External timing resistance
Cext
External timing capacitance
∆t/∆VCC
TA
Power-up ramp rate
5.5
VCC × 0.7
VCC × 0.7
Input voltage
Low level output current
Low-level
2
VCC × 0.7
VCC × 0.7
VI
VO
IOL
MAX
1.5
Low level input voltage
Low-level
High level output current
High-level
MIN
1.5
VIL
IOH
SN74LV123A
MIN
VCC = 3 V to 3.6 V
VCC = 4.5 V to 5.5 V
0.5
0.5
VCC × 0.3
VCC × 0.3
VCC = 2 V
VCC = 2.3 V to 2.7 V
VCC
–50
0
VCC × 0.3
5.5
0
–2
VCC = 3 V to 3.6 V
VCC = 4.5 V to 5.5 V
VCC
–50
–6
–6
–12
VCC = 2 V
VCC = 2.3 V to 2.7 V
50
50
2
2
VCC = 3 V to 3.6 V
VCC = 4.5 V to 5.5 V
6
6
12
12
5k
5k
1k
1k
No restriction
–55
V
µA
–40
mA
µA
mA
pF
1
125
V
Ω
No restriction
1
Operating free-air temperature
V
–2
–12
VCC = 2 V
VCC ≥ 3 V
V
V
VCC × 0.3
VCC × 0.3
VCC × 0.3
5.5
UNIT
ms/V
85
°C
NOTE 4: All unused inputs of the device must be held at VCC or GND to ensure proper device operation. Refer to the TI application report,
Implications of Slow or Floating CMOS Inputs, literature number SCBA004.
PRODUCT PREVIEW information concerns products in the formative or
design phase of development. Characteristic data and other
specifications are design goals. Texas Instruments reserves the right to
change or discontinue these products without notice.
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5
SN54LV123A, SN74LV123A
DUAL RETRIGGERABLE MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SCLS393A – APRIL 1998 – REVISED DECEMBER 1999
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
PARAMETER
IOL = 50 µA
IOL = 2 mA
IOL = 6 mA
IOL = 12 mA
VI = VCC or GND
Rext/Cext†
ICC
A B,
A,
B and CLR
VI = VCC or GND
Quiescent
VI = VCC or GND,
Active state
(per circuit)
Ioff
IO = 0
VI = VCC or GND,,
Rext/Cext = 0.5 VCC
TYP
SN74LV123A
MAX
MIN
2.3 V
VCC–0.1
2
VCC–0.1
2
3V
2.48
2.48
4.5 V
3.8
TYP
UNIT
V
3.8
0.1
0.1
2.3 V
0.4
0.4
3V
0.44
0.44
4.5 V
0.55
0.55
2 V to 5.5 V
±2.5
±2.5
0V
±1
±1
5.5 V
±1
±1
5.5 V
20
20
2.3 V
220
220
3V
280
280
4.5 V
650
650
5.5 V
975
975
0V
VI = VCC or GND
MAX
2 V to 5.5 V
VI or VO = 0 to 5.5 V
Ci
MIN
2 V to 5.5 V
IOH = –6 mA
IOH = –12 mA
VOL
ICC
VCC
IOH = –50 µA
IOH = –2 mA
VOH
II
SN54LV123A
TEST CONDITIONS
5
3.3 V
1.9
1.9
5V
1.9
1.9
V
µA
µA
µA
µA
pF
† This test is performed with the terminal in the off-state condition.
timing requirements over recommended operating free-air temperature range, VCC = 2.5 V ± 0.2 V
(unless otherwise noted) (see Figure 1)
TEST CONDITIONS
MIN
TA = 25°C
TYP
MAX
SN54LV123A
MIN
MAX
SN74LV123A
MIN
CLR
6
6.5
6.5
A or B trigger
6
‡
94
6.5
‡
6.5
‡
2
‡
‡
tw
Pulse
duration
trr
Pulse retrigger time
Rextt = 1 kΩ
Cext = 100 pF
Cext = 0.01 mF
‡ See retriggering data in the application information section.
‡
MAX
UNIT
ns
ns
ms
timing requirements over recommended operating free-air temperature range, VCC = 3.3 V ± 0.3 V
(unless otherwise noted) (see Figure 1)
TA = 25°C
MIN
TYP
MAX
TEST CONDITIONS
MIN
MAX
SN74LV123A
MIN
CLR
5
5
5
A or B trigger
Cext = 100 pF
5
‡
76
5
‡
5
‡
Cext = 0.01 mF
‡
1.8
‡
‡
tw
Pulse
duration
trr
Pulse retrigger time
Rextt = 1 kΩ
‡ See retriggering data in the application information section.
PRODUCT PREVIEW information concerns products in the formative or
design phase of development. Characteristic data and other
specifications are design goals. Texas Instruments reserves the right to
change or discontinue these products without notice.
6
SN54LV123A
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MAX
UNIT
ns
ns
ms
SN54LV123A, SN74LV123A
DUAL RETRIGGERABLE MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SCLS393A – APRIL 1998 – REVISED DECEMBER 1999
timing requirements over recommended operating free-air temperature range, VCC = 5 V ± 0.5 V
(unless otherwise noted) (see Figure 1)
TEST CONDITIONS
MIN
TA = 25°C
TYP
MAX
SN54LV123A
MIN
MAX
SN74LV123A
MIN
CLR
5
5
5
A or B trigger
5
†
59
5
†
5
†
1.5
†
†
tw
Pulse
duration
trr
Pulse retrigger time
Rextt = 1 kΩ
Cext = 100 pF
Cext = 0.01 mF
† See retriggering data in the application information section.
†
MAX
UNIT
ns
ns
ms
switching characteristics over recommended operating free-air temperature range,
VCC = 2.5 V ± 0.2 V (unless otherwise noted) (see Figure 1)
PARAMETER
tpd
tpd
tw‡
FROM
(INPUT)
TO
(OUTPUT)
A or B
Q or Q
CLR
Q or Q
CLR trigger
A or B
CLR
Q or Q
CLR trigger
Q or Q
TEST
CONDITIONS
MIN
TA = 25°C
TYP
MAX
SN54LV123A
SN74LV123A
MIN
MAX
MIN
MAX
14.5*
31.4*
1*
37*
11
37
13*
25*
1*
29.5*
1
29.5
Q or Q
15.1*
33.4*
1*
39*
1
39
Q or Q
16.6
36
1
42
1
42
14.7
32.8
1
34.5
1
34.5
17.4
38
1
44
1
44
197
260
90
100
110
90
110
0.9
1
1.1
0.9
1.1
Q or Q
CL = 15 pF
CL = 50 pF
CL = 50 pF,
Cext = 28 pF,
Rext = 2 kΩ
CL = 50 pF,
Cext = 0.01 µF,
Rext = 10 kΩ
CL = 50 pF,
Cext = 0.1 µF,
Rext = 10 kΩ
∆tw§
±1
CL = 50 pF
320
UNIT
ns
ns
320
ns
90
110
ms
0.9
1.1
ms
%
* On products compliant to MIL-PRF-38535, this parameter is not production tested.
‡ tw = Duration of pulse at Q and Q outputs
§ ∆tw = Output pulse duration variation (Q and Q) between circuits in same package
PRODUCT PREVIEW information concerns products in the formative or
design phase of development. Characteristic data and other
specifications are design goals. Texas Instruments reserves the right to
change or discontinue these products without notice.
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7
SN54LV123A, SN74LV123A
DUAL RETRIGGERABLE MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SCLS393A – APRIL 1998 – REVISED DECEMBER 1999
switching characteristics over recommended operating free-air temperature range,
VCC = 3.3 V ± 0.3 V (unless otherwise noted) (see Figure 1)
PARAMETER
tpd
tpd
TEST
CONDITIONS
TA = 25°C
TYP
MAX
FROM
(INPUT)
TO
(OUTPUT)
A or B
Q or Q
10.2*
20.6*
9.3*
15.8*
MIN
CL = 15 pF
SN54LV123A
MIN
SN74LV123A
MAX
MIN
MAX
1*
24*
1
24
1*
18.5*
1
18.5
CLR
Q or Q
CLR trigger
Q or Q
10.6*
22.4*
1*
26*
1
26
A or B
Q or Q
11.8
24.1
1
27.5
1
27.5
CLR
Q or Q
10.5
19.3
1
22
1
22
CLR trigger
Q or Q
12.3
25.9
1
29.5
1
29.5
182
240
90
100
110
90
110
0.9
1
1.1
0.9
1.1
tw†
CL = 50 pF
CL = 50 pF,
Cext = 28 pF,
Rext = 2 kΩ
CL = 50 pF,
Cext = 0.01 µF,
Rext = 10 kΩ
CL = 50 pF,
Cext = 0.1 µF,
Rext = 10 kΩ
Q or Q
∆tw‡
300
ns
ns
300
ns
90
110
ms
0.9
1.1
ms
±1
CL = 50 pF
UNIT
%
* On products compliant to MIL-PRF-38535, this parameter is not production tested.
† tw = Duration of pulse at Q and Q outputs
‡ ∆tw = Output pulse duration variation (Q and Q) between circuits in same package
switching characteristics over recommended operating free-air temperature range,
VCC = 5 V ± 0.5 V (unless otherwise noted) (see Figure 1)
PARAMETER
tpd
tpd
tw†
FROM
(INPUT)
TO
(OUTPUT)
A or B
Q or Q
CLR
Q or Q
TEST
CONDITIONS
MIN
TA = 25°C
TYP
MAX
MAX
MIN
MAX
12*
1*
14*
1
14
6.5*
9.4*
1*
11*
1
11
12.9*
1*
15*
1
15
CLR trigger
Q or Q
7.4*
A or B
Q or Q
8.3
14
1
16
1
16
CLR
Q or Q
7.4
11.4
1
13
1
13
CLR trigger
Q or Q
8.7
14.9
1
17
1
17
167
200
90
100
110
90
110
0.9
1
1.1
0.9
1.1
Q or Q
CL = 50 pF
CL = 50 pF,
Cext = 28 pF,
Rext = 2 kΩ
CL = 50 pF,
Cext = 0.01 µF,
Rext = 10 kΩ
CL = 50 pF,
Cext = 0.1 µF,
Rext = 10 kΩ
∆tw‡
±1
* On products compliant to MIL-PRF-38535, this parameter is not production tested.
† tw = Duration of pulse at Q and Q outputs
‡ ∆tw = Output pulse duration variation (Q and Q) between circuits in same package
PRODUCT PREVIEW information concerns products in the formative or
design phase of development. Characteristic data and other
specifications are design goals. Texas Instruments reserves the right to
change or discontinue these products without notice.
8
SN74LV123A
MIN
7.1*
CL = 15 pF
SN54LV123A
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240
UNIT
ns
ns
240
ns
90
110
ms
0.9
1.1
ms
%
SN54LV123A, SN74LV123A
DUAL RETRIGGERABLE MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SCLS393A – APRIL 1998 – REVISED DECEMBER 1999
operating characteristics, TA = 25°C
PARAMETER
Cpd
d
TEST CONDITIONS
Power dissipation capacitance
pF
CL = 50 pF,
f = 10 MHz
VCC
3.3 V
TYP
5V
49
44
UNIT
pF
PARAMETER MEASUREMENT INFORMATION
From Output
Under Test
Test
Point
tw
CL
(see Note A)
VCC
Inputs or
Outputs
50% VCC
50% VCC
0V
LOAD CIRCUIT
VOLTAGE WAVEFORMS
PULSE DURATION
VCC
Input A
(see Note B)
50% VCC
0V
VCC
Input B
(see Note B)
50% VCC
50% VCC
0V
50% VCC
VOH
In-Phase
Output
50% VCC
In-Phase
Output
VOL
VOH
VOL
50% VCC
Out-of-Phase
Output
VOLTAGE WAVEFORMS
DELAY TIMES
VOH
50% VCC
VOL
tPLH
tPHL
tPHL
50% VCC
tPHL
tPLH
0V
tPLH
Out-of-Phase
Output
VCC
Input CLR
(see Note B)
50% VCC
VOH
50% VCC
VOL
VOLTAGE WAVEFORMS
DELAY TIMES
NOTES: A. CL includes probe and jig capacitance.
B. All input pulses are supplied by generators having the following characteristics: PRR ≤ 1 MHz, ZO = 50 Ω, tr
C. The outputs are measured one at a time with one input transition per measurement.
+ 3 ns, tf + 3 ns.
Figure 1. Load Circuit and Voltage Waveforms
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9
SN54LV123A, SN74LV123A
DUAL RETRIGGERABLE MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SCLS393A – APRIL 1998 – REVISED DECEMBER 1999
APPLICATION INFORMATION
caution in use
To prevent malfunctions due to noise, connect a high-frequency capacitor between VCC and GND, and keep
the wiring between the external components and Cext and Rext/Cext terminals as short as possible.
power-down considerations
Large values of Cext may cause problems when powering down the ’LV123A because of the amount of energy
stored in the capacitor. When a system containing this device is powered down, the capacitor may discharge
from VCC through the protection diodes at pin 2 or pin 14. Current through the input protection diodes must be
limited to 30 mA; therefore, the turn-off time of the VCC power supply must not be faster than
t = VCC × Cext/30 mA. For example, if VCC = 5 V and Cext = 15 pF, the VCC supply must turn off no faster than
t = (5 V) × (15 pF)/30mA = 2.5 ms. Usually, this is not a problem because power supplies are heavily filtered
and cannot discharge at this rate. When a more rapid decrease of VCC to zero occurs, the ’LV123A may sustain
damage. To avoid this possibility, use external clamping diodes.
output pulse duration
The output pulse duration, tw, is determined primarily by the values of the external capacitance (CT) and timing
resistance (RT). The timing components are connected as shown in Figure 2.
VCC
RT
CT
To Rext/Cext
Terminal
To Cext
Terminal
Figure 2. Timing-Component Connections
The pulse duration is given by:
tw
+K
RT
CT
(1)
if CT is ≥ 1000 pF, K = 1.0
or
if CT is < 1000 pF, K can be determined from Figure 9
where:
tw
RT
CT
K
= pulse duration in ns
= external timing resistance in kΩ
= external capacitance in pF
= multiplier factor
Equation 1 and Figures 5 or 6 can be used to determine values for pulse duration, external resistance, and
external capacitance.
10
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
SN54LV123A, SN74LV123A
DUAL RETRIGGERABLE MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SCLS393A – APRIL 1998 – REVISED DECEMBER 1999
APPLICATION INFORMATION
retriggering data
The minimum input retriggering time (tMIR) is the minimum time required after the initial signal before retriggering the
input. After tMIR, the device retriggers the output. Experimentally, it also can be shown that, to retrigger the output
pulse, the two adjacent input signals should be tMIR apart, where tMIR = 0.30 × tw. The retrigger pulse duration is
calculated as shown in Figure 3.
tMIR
Input
tRT = tw + tPLH = (K × RT × CT) + tPLH
tRT
tw
tPLH
Output
Where:
tMIR = Minimum Input Retriggering Time
tPLH = Propagation Delay
tRT = Retrigger Time
tw
= Output Pulse Duration Before Retriggering
Figure 3. Retrigger Pulse Duration
The minimum value from the end of the input pulse to the beginning of the retriggered output should be approximately
15 ns to ensure a retriggered output. This is illustrated in Figure 4.
Input
tMRT
Output
tMRT = Minimum Time Between the End of the Second Input Pulse and the Beginning of the Retriggered Output
tMRT = 15 ns
Figure 4. Input/Output Requirements
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
11
SN54LV123A, SN74LV123A
DUAL RETRIGGERABLE MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SCLS393A – APRIL 1998 – REVISED DECEMBER 1999
APPLICATION INFORMATION†
OUTPUT PULSE DURATION
vs
EXTERNAL TIMING CAPACITANCE
1.00E+07
VCC = 3 V
TA = 25°C
1.00E+06
t w – Output Pulse Duration – ns
t w – Output Pulse Duration – ns
1.00E+07
OUTPUT PULSE DURATION
vs
EXTERNAL TIMING CAPACITANCE
RT = 1 MΩ
1.00E+05
RT = 100 kΩ
1.00E+04
RT = 10 kΩ
1.00E+03
1.00E+06
RT = 1 MΩ
1.00E+05
RT = 100 kΩ
1.00E+04
RT = 10 kΩ
1.00E+03
RT = 1 kΩ
1.00E+02
101
VCC = 4.5 V
TA = 25°C
RT = 1 kΩ
102
103
104
105
1.00E+02
101
102
103
104
105
CT – External Timing Capacitance – pF
CT – External Timing Capacitance – pF
Figure 5
Figure 6
VARIATION IN OUTPUT PULSE DURATION
vs
TEMPERATURE
14%
Variation in Output Pulse Duration
12%
10%
8%
tw = 866 ns at:
VCC = 5 V
RT = 10 kΩ
CT = 50 pF
TA = 25°C
VCC = 2.5 V
VCC = 3 V
VCC = 3.5 V
VCC = 4 V
6%
VCC = 5 V
VCC = 6 V
4%
VCC = 7 V
2%
0%
–2%
–4%
–6%
–60
–40
–20
0
20
40
60
80
100
120
140
160
180
Temperature – °C
Figure 7
† Operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not implied.
12
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
SN54LV123A, SN74LV123A
DUAL RETRIGGERABLE MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SCLS393A – APRIL 1998 – REVISED DECEMBER 1999
APPLICATION INFORMATION†
MINIMUM TRIGGER TIME
vs
VCC CHARACTERISTICS
OUTPUT PULSE DURATION CONSTANT
vs
SUPPLY VOLTAGE
10.00
1.20
Output Pulse Duration Constant – K
t rr – Minimum Retrigger Time – µs
RT = 1 kΩ
TA = 25°C
CT = 0.01 µF
1.00
CT = 1000 pF
0.10
CT = 100 pF
0.01
0
1
2
3
4
5
6
RT = 10 kΩ
TA = 25°C
tw = K × C T × R T
1.15
1.10
CT = 1000 pF
1.05
CT = 0.01 µF
1.00
CT = 0.1 µF
0.95
0.90
1.5
2
VCC – Supply Voltage – V
2.5
3
3.5
4
4.5 5
VCC – Supply Voltage – V
Figure 8
6
Figure 9
DISTRIBUTION OF UNITS
vs
OUTPUT PULSE DURATION
EXTERNAL CAPACITANCE
vs
MULTIPLIER FACTOR
0.001
For Capacitor Values of
0.001 µF or Greater, K = 1.0
(K is Independent of R)
Relative Frequency of Occurrence
C T – External Capacitor Value – µ F
5.5
0.0001
VCC = 5 V
TA = 25°C
CT = 50 pF
RT = 10 kΩ
Mean = 856 ns
Median = 856 ns
Std. Dev. = 3.5 ns
TA = 25°C
VCC = 5 V
0.00001
1.00
–3 Std. Dev.
1.50 2.00
2.50 3.00
3.50 4.00
4.50
+3 Std. Dev.
99% of Data Units
Multiplier Factor – K
Median
tw – Output Pulse Duration
Figure 10
Figure 11
† Operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not implied.
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
13
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