SN74LV221APW [TI]
DUAL MONOSTABLE MULTIVIBRATORS WITH SCHMITT-TRIGGER INPUTS; 施密特触发器输入双单稳态触发器
| 型号： | SN74LV221APW |
| 厂家： | 
TEXAS INSTRUMENTS |
| 描述： | DUAL MONOSTABLE MULTIVIBRATORS WITH SCHMITT-TRIGGER INPUTS |
| 文件： | 总13页 (文件大小：211K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
SN54LV221A, SN74LV221A
DUAL MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SCLS450 – DECEMBER 1999
SN54LV221A . . . J OR W PACKAGE
SN74LV221A . . . D, DB, DGV, NS, OR PW PACKAGE
(TOP VIEW)
EPIC (Enhanced-Performance Implanted
CMOS) Process
Schmitt-Trigger Circuitry on A, B, and CLR
Inputs for Slow Input Transition Rates
1A
1B
V
CC
1
2
3
4
5
6
7
8
16
15
14
13
1R /C
Edge Triggered From Active-High or
Active-Low Gated Logic Inputs
ext ext
1CLR
1Q
1C
1Q
ext
Overriding Clear Terminates Output Pulse
Glitch-Free Power-Up Reset on Outputs
2Q
12 2Q
11
10
9
2C
2CLR
2B
ext
Latch-Up Performance Exceeds 100 mA Per
JESD 78, Class II
2R /C
ext ext
GND
2A
ESD Protection Exceeds JESD 22
– 2000-V Human-Body Model (A114-A)
– 200-V Machine Model (A115-A)
SN54LV221A . . . FK PACKAGE
(TOP VIEW)
– 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)
3
2
1 20 19
18
1C
1Q
1CLR
1Q
4
5
6
7
8
ext
17
16
NC
NC
description
15 2Q
14
2Q
The ’LV221A devices are dual multivibrators
designed for 2-V to 5.5-V V operation. Each
2CLR
2C
ext
9 10 11 12 13
CC
multivibrator has a negative-transition-triggered
(A) input and a positive-transition-triggered (B)
input, either of which can be used as an inhibit
input.
NC – No internal connection
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 and V . Toobtainvariablepulsedurations, connectanexternalvariableresistor
ext ext
CC
between and R /C and V . The output pulse duration can also be reduced by taking CLR low.
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.
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.
1
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
SN54LV221A, SN74LV221A
DUAL MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SCLS450 – DECEMBER 1999
description (continued)
Once triggered, the outputs are independent of further transitions of the A and B inputs and are a function of
the timing components, or the output pulses can be terminated by the overriding clear. Input pulses may be of
any duration relative to the output pulse. Output pulse duration can be varied by choosing the appropriate timing
components. OutputriseandfalltimesareTTLcompatibleandindependentofpulseduration. Typicaltriggering
and clearing sequences are illustrated in the input/output timing diagram.
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 ’LV221A is shown in Figure 8. Variations in output pulse
duration versus supply voltage and temperature are shown in Figure 5.
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 are identical to those of the ’AHC123A and ’AHCT123A devices, so the ’LV221A can be
substituted for those devices not using the retrigger feature.
The SN54LV221A is characterized for operation over the full military temperature range of –55°C to 125°C.
The SN74LV221A 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
FUNCTION
A
X
H
X
L
B
X
X
L
Q
L
L
L
Q
H
H
H
CLR
L
Reset
Inhibit
H
H
Inhibit
H
↑
Outputs enabled
Outputs enabled
Outputs enabled
H
H
H
†
↑
L
†
This condition is true only if the output of the latch formed by the
NANDgatehasbeenconditionedtothelogic1statepriortoCLR
going high. This latch is conditioned by taking either A high or B
low while CLR is inactive (high).
2
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
SN54LV221A, SN74LV221A
DUAL MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SCLS450 – DECEMBER 1999
†
logic symbol
1
2
&
1A
1B
13
1Q
4
3
R
1CLR
1Q
14
15
CX
1C
ext
RX/CX
&
1R /C
ext ext
9
2A
2B
10
5
2Q
12
2Q
11
6
R
2CLR
CX
2C
ext
7
RX/CX
2R /C
ext ext
†
This symbol is in accordance with ANSI/IEEE Std 91-1984 and IEC Publication 617-12.
Pin numbers shown are for the D, DB, DGV, J, NS, PW, and W packages.
logic diagram, each multivibrator (positive logic)
R
C
/C
ext ext
A
B
ext
Q
Q
CLR
R
3
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
SN54LV221A, SN74LV221A
DUAL MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SCLS450 – DECEMBER 1999
input/output timing diagram
A
B
CLR
R
/C
ext ext
Q
Q
t
t
t
+ t
w rr
w
w
†
absolute maximum ratings over operating free-air temperature (unless otherwise noted)
Supply voltage range, V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.5 V to 7 V
CC
Input voltage range, V (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.5 V to 7 V
I
Output voltage range in high or low state, V (see Notes 1 and 2) . . . . . . . . . . . . . . . . . –0.5 V to V
+ 0.5 V
O
CC
Output voltage range in power-off state, V (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.5 V to 7 V
O
Input clamp current, I (V < 0) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –20 mA
IK
I
Output clamp current, I
(V < 0 or V > V ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±50 mA
OK
O O CC
Continuous output current, I (V = 0 to V ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±25 mA
Continuous current through V
Package thermal impedance, θ (see Note 3): D package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73°C/W
O
O
CC
CC
or GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±50 mA
JA
DB package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82°C/W
DGV package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120°C/W
NS package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64°C/W
PW package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108°C/W
Storage temperature range, T
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –65°C to 150°C
stg
†
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
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
SN54LV221A, SN74LV221A
DUAL MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SCLS450 – DECEMBER 1999
recommended operating conditions (see Note 4)
SN54LV221A
SN74LV221A
UNIT
MIN
2
MAX
MIN
2
MAX
V
V
Supply voltage
5.5
5.5
V
CC
V
CC
V
CC
V
CC
V
CC
V
CC
V
CC
V
CC
V
CC
= 2 V
1.5
1.5
= 2.3 V to 2.7 V
= 3 V to 3.6 V
= 4.5 V to 5.5 V
= 2 V
V
CC
V
CC
V
CC
× 0.7
× 0.7
× 0.7
V
CC
V
CC
V
CC
× 0.7
× 0.7
× 0.7
High-level input voltage
V
V
IH
0.5
× 0.3
× 0.3
× 0.3
5.5
0.5
× 0.3
× 0.3
× 0.3
5.5
= 2.3 V to 2.7 V
= 3 V to 3.6 V
= 4.5 V to 5.5 V
V
CC
V
CC
V
CC
V
CC
V
CC
V
CC
V
IL
Low-level input voltage
V
V
Input voltage
0
0
0
0
V
V
I
Output voltage
V
CC
V
CC
O
V
CC
V
CC
V
CC
V
CC
V
CC
V
CC
V
CC
V
CC
V
CC
V
CC
= 2 V
–50
–2
–6
–12
50
2
–50
–2
–6
–12
50
2
µA
= 2.3 V to 2.7 V
= 3 V to 3.6 V
= 4.5 V to 5.5 V
= 2 V
I
High-level output current
OH
OL
mA
µA
= 2.3 V to 2.7 V
= 3 V to 3.6 V
= 4.5 V to 5.5 V
= 2 V
I
Low-level output current
External timing resistance
6
6
mA
12
12
5k
1k
5k
1k
R
C
Ω
ext
ext
≥ 3 V
External timing capacitance
Power-up ramp rate
No restriction
No restriction
pF
ms/V
°C
∆t/∆V
CC
1
1
T
Operating free-air temperature
–55
125
–40
85
A
NOTE 4: All unused inputs of the device must be held at V
or GND to ensure proper device operation. Refer to the TI application report,
CC
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.
5
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
SN54LV221A, SN74LV221A
DUAL MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SCLS450 – DECEMBER 1999
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
SN54LV221A
SN74LV221A
PARAMETER
TEST CONDITIONS
UNIT
V
CC
MIN
–0.1
2
TYP
MAX
MIN
–0.1
2
TYP
MAX
I
I
I
I
I
I
I
I
= –50 µA
= –2 mA
= –6 mA
= –12 mA
= 50 µA
= 2 mA
2 V to 5.5 V
2.3 V
3 V
V
CC
V
CC
OH
OH
OH
OH
OL
OL
OL
OL
V
V
OH
2.48
3.8
2.48
3.8
4.5 V
2 V to 5.5 V
2.3 V
3 V
0.1
0.4
0.1
0.4
0.44
0.55
±2.5
±1
V
V
OL
= 6 mA
0.44
0.55
±2.5
±1
= 12 mA
4.5 V
2 V to 5.5 V
0 V
V = V
I
or GND
or GND
or GND,
R
/C †
ext ext
CC
CC
CC
I
I
µA
µA
I
V = V
I
A, B, and CLR
Quiescent
5.5 V
5.5 V
2.3 V
3 V
±1
±1
V = V
I = 0
O
20
20
CC
CC
off
I
220
280
650
975
220
280
650
975
5
Active state
(per circuit)
V = V
/C
ext ext
or GND,
= 0.5 V
I
CC
I
µA
R
4.5 V
5.5 V
0 V
CC
I
V or V = 0 to 5.5 V
µA
I
O
3.3 V
5 V
1.9
1.9
1.9
1.9
C
V = V
I
or GND
pF
i
CC
†
This test is performed with the terminal in the off-state condition.
timing requirements over recommended operating free-air temperature range, V
(unless otherwise noted) (see Figure 1)
= 2.5 V ± 0.2 V
CC
T
A
= 25°C
SN54LV221A SN74LV221A
TEST CONDITIONS
UNIT
MIN
6
TYP
MAX
MIN
6.5
MAX
MIN
6.5
MAX
CLR
t
w
Pulse duration
ns
A or B trigger
6
6.5
6.5
timing requirements over recommended operating free-air temperature range, V
(unless otherwise noted) (see Figure 1)
= 3.3 V ± 0.3 V
CC
T
A
= 25°C
SN54LV221A SN74LV221A
TEST CONDITIONS
UNIT
MIN
5
TYP
MAX
MIN
5
MAX
MIN
5
MAX
CLR
t
w
Pulse duration
ns
A or B trigger
5
5
5
timing requirements over recommended operating free-air temperature range, V
(unless otherwise noted) (see Figure 1)
= 5 V ± 0.5 V
CC
T
A
= 25°C
SN54LV221A SN74LV221A
TEST CONDITIONS
UNIT
MIN
5
TYP
MAX
MIN
5
MAX
MIN
5
MAX
CLR
t
w
Pulse duration
ns
A or B trigger
5
5
5
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
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
SN54LV221A, SN74LV221A
DUAL MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SCLS450 – DECEMBER 1999
switching characteristics over recommended operating free-air temperature range,
V
= 2.5 V ± 0.2 V (unless otherwise noted) (see Figure 1)
CC
T = 25°C
A
SN54LV221A SN74LV221A
FROM
(INPUT)
TO
(OUTPUT)
TEST
CONDITIONS
PARAMETER
UNIT
MIN
TYP
MAX
MIN
MAX
MIN
MAX
14.6* 31.4*
13.2* 25*
15.2* 33.4*
1*
37*
1
37
A or B
CLR
Q or Q
Q or Q
Q or Q
Q or Q
Q or Q
Q or Q
1* 29.5*
1
1
1
1
1
29.5
39
t
C
C
= 15 pF
ns
pd
L
1*
1
39*
42
CLR trigger
A or B
16.7
15
36
32.8
38
42
1
34.5
44
34.5
44
t
pd
= 50 pF
= 50 pF,
= 28 pF,
= 2 kΩ
ns
CLR
L
17.4
1
CLR trigger
C
L
C
R
203
100
260
110
1.1
320
110
1.1
320
110
1.1
ns
s
ext
ext
C
= 50 pF,
= 0.01 µF,
= 10 kΩ
L
†
t
C
90
90
90
Q or Q
ext
w
R
ext
C
= 50 pF,
= 0.1 µF,
= 10 kΩ
L
C
R
0.9
1
0.9
0.9
ms
%
ext
ext
‡
∆t
C
= 50 pF
L
±1
w
* On products compliant to MIL-PRF-38535, this parameter is not production tested.
†
‡
t
= Duration of pulse at Q and Q outputs
w
∆t = Output pulse duration variation (Q and Q) between circuits in same package
w
switching characteristics over recommended operating free-air temperature range,
V
= 3.3 V ± 0.3 V (unless otherwise noted) (see Figure 1)
CC
T = 25°C
A
SN54LV221A
SN74LV221A
FROM
(INPUT)
TO
(OUTPUT)
TEST
CONDITIONS
PARAMETER
UNIT
MIN
TYP
MAX
MIN
MAX
MIN
MAX
10.2* 20.6*
9.3* 15.8*
10.6* 22.4*
1*
24*
1
24
A or B
CLR
Q or Q
Q or Q
Q or Q
Q or Q
Q or Q
Q or Q
1* 18.5*
1
1
1
1
1
18.5
26
t
C
C
= 15 pF
ns
pd
L
1*
1
26*
27.5
22
CLR trigger
A or B
11.8
10.6
12.3
24.1
19.3
25.9
27.5
22
1
t
pd
= 50 pF
= 50 pF,
= 28 pF,
= 2 kΩ
ns
CLR
L
1
29.5
29.5
CLR trigger
C
L
C
R
186
100
240
110
1.1
300
110
1.1
300
110
1.1
ns
s
ext
ext
C
= 50 pF,
= 0.01 µF,
= 10 kΩ
L
†
t
C
90
90
90
Q or Q
ext
w
R
ext
C
= 50 pF,
= 0.1 µF,
= 10 kΩ
L
C
R
0.9
1
0.9
0.9
ms
%
ext
ext
‡
∆t
C
= 50 pF
L
±1
w
* On products compliant to MIL-PRF-38535, this parameter is not production tested.
†
‡
t
= Duration of pulse at Q and Q outputs
w
∆t = Output pulse duration variation (Q and Q) between circuits in same package
w
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.
7
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
SN54LV221A, SN74LV221A
DUAL MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SCLS450 – DECEMBER 1999
switching characteristics over recommended operating free-air temperature range,
V
= 5 V ± 0.5 V (unless otherwise noted) (see Figure 1)
CC
T
A
= 25°C
TYP
SN54LV221A SN74LV221A
FROM
(INPUT)
TO
(OUTPUT)
TEST
CONDITIONS
PARAMETER
UNIT
MIN
MAX
MIN
MAX
MIN
MAX
7.1*
12*
1*
14*
1
14
A or B
CLR
Q or Q
Q or Q
Q or Q
Q or Q
Q or Q
Q or Q
6.5*
9.4*
1*
1*
1
11*
15*
16
1
1
1
1
1
11
15
16
13
17
t
pd
C
C
= 15 pF
ns
L
7.3* 12.9*
CLR trigger
A or B
8.2
7.4
8.6
14
11.4
14.9
1
13
t
pd
= 50 pF
= 50 pF,
= 28 pF,
= 2 kΩ
ns
CLR
L
1
17
CLR trigger
C
L
C
R
171
100
200
110
1.1
240
110
1.1
240
110
1.1
ns
s
ext
ext
C
= 50 pF,
= 0.01 µF,
= 10 kΩ
L
†
t
C
90
90
90
Q or Q
ext
w
R
ext
C
= 50 pF,
= 0.1 µF,
= 10 kΩ
L
C
R
0.9
1
0.9
0.9
ms
%
ext
ext
‡
∆t
w
C
= 50 pF
L
±1
* On products compliant to MIL-PRF-38535, this parameter is not production tested.
†
‡
t
= Duration of pulse at Q and Q outputs
w
∆t = Output pulse duration variation (Q and Q) between circuits in same package
w
operating characteristics, T = 25°C
A
PARAMETER
TEST CONDITIONS
= 50 pF, f = 10 MHz
L
V
TYP
50
UNIT
CC
3.3 V
C
Power dissipation capacitance
C
pF
pd
5 V
51
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
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
SN54LV221A, SN74LV221A
DUAL MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SCLS450 – DECEMBER 1999
PARAMETER MEASUREMENT INFORMATION
From Output
Under Test
Test
Point
t
w
V
CC
C
L
Inputs or
Outputs
(see Note A)
50% V
50% V
CC
CC
0 V
LOAD CIRCUIT
VOLTAGE WAVEFORMS
PULSE DURATION
V
CC
Input A
(see Note B)
50% V
CC
0 V
V
V
CC
Input CLR
(see Note B)
50% V
50% V
CC
CC
t
CC
Input B
0 V
50% V
(see Note B)
CC
t
t
0 V
PLH
PHL
t
t
V
OH
PLH
In-Phase
Output
V
V
OH
50% V
50% V
CC
CC
V
In-Phase
Output
50% V
CC
OL
OL
t
PHL
PLH
PHL
V
V
V
OH
OH
Out-of-Phase
Output
Out-of-Phase
Output
50% V
50% V
50% V
CC
CC
V
CC
OL
OL
VOLTAGE WAVEFORMS
DELAY TIMES
VOLTAGE WAVEFORMS
DELAY TIMES
NOTES: A.
C includes probe and jig capacitance.
L
B. All input pulses are supplied by generators having the following characteristics: PRR ≤ 1 MHz, Z = 50 Ω, t
C. The outputs are measured one at a time with one input transition per measurement.
3 ns, t
f
3 ns.
O
r
Figure 1. Load Circuit and Voltage Waveforms
9
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
SN54LV221A, SN74LV221A
DUAL MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SCLS450 – DECEMBER 1999
APPLICATION INFORMATION
caution in use
To prevent malfunctions due to noise, connect a high-frequency capacitor between V
and GND, and keep
CC
the wiring between the external components and C and R /C terminals as short as possible.
ext
ext ext
power-down considerations
Large values of C can cause problems when powering down the ’LV221A because of the amount of energy
ext
stored in the capacitor. When a system containing this device is powered down, the capacitor can discharge
from V
through the protection diodes at pin 2 or pin 14. Current through the input protection diodes must be
CC
limited to 30 mA; therefore, the turn-off time of the V
power supply must not be faster than
CC
t = V
× C /30 mA. For example, if V
= 5 V and C = 15 pF, the V
supply must turn off no faster than
CC
ext
CC
ext
CC
t = (5 V) × (15 pF)/30 mA = 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 V
damage. To avoid this possibility, use external clamping diodes.
to zero occurs, the ’LV221A can sustain
CC
output pulse duration
The output pulse duration, t , is determined primarily by the values of the external capacitance (C ) and timing
w
T
resistance (R ). The timing components are connected as shown in Figure 2.
T
V
CC
R
T
C
T
To R /C
ext ext
Terminal
To C
ext
Terminal
Figure 2. Timing-Component Connections
The pulse duration is given by:
tw
K
RT CT
(1)
if C is ≥ 1000 pF, K = 1.0
T
or
if C is < 1000 pF, K can be determined from Figure 7
T
where:
t
= pulse duration in ns
w
R
C
K
= external timing resistance in kΩ
= external capacitance in pF
= multiplier factor
T
T
Equation 1 and Figure 3 or 4 can be used to determine values for pulse duration, external resistance, and
external capacitance.
10
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
SN54LV221A, SN74LV221A
DUAL MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SCLS450 – DECEMBER 1999
†
APPLICATION INFORMATION
OUTPUT PULSE DURATION
vs
OUTPUT PULSE DURATION
vs
EXTERNAL TIMING CAPACITANCE
EXTERNAL TIMING CAPACITANCE
1.00E+07
1.00E+06
1.00E+07
1.00E+06
V
T
A
= 3 V
V
= 4.5 V
CC
= 25°C
CC
T = 25°C
A
R
= 1 MΩ
R
= 1 MΩ
T
T
1.00E+05
1.00E+04
1.00E+05
1.00E+04
R
= 100 kΩ
R
= 100 kΩ
T
T
T
T
R
= 10 kΩ
= 1 kΩ
R
= 10 kΩ
= 1 kΩ
1.00E+03
1.00E+02
1.00E+03
1.00E+02
R
R
T
T
1
2
10
3
10
4
10
5
10
1
2
10
3
10
4
10
5
10
10
10
C
– External Timing Capacitance – pF
C
– External Timing Capacitance – pF
T
T
Figure 3
Figure 4
VARIATION IN OUTPUT PULSE DURATION
vs
TEMPERATURE
14%
12%
10%
t
= 866 ns at:
= 5 V
= 10 kΩ
= 50 pF
= 25°C
w
CC
T
T
A
V
R
C
V
= 2.5 V
CC
V
CC
V
CC
V
CC
= 3 V
T
= 3.5 V
= 4 V
8%
6%
4%
2%
V
CC
V
CC
V
CC
= 5 V
= 6 V
= 7 V
0%
–2%
–4%
–6%
–60
–40
–20
0
20
40
60
80
100
120
140
160
180
Temperature – °C
Figure 5
†
Operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not implied.
11
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
SN54LV221A, SN74LV221A
DUAL MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SCLS450 – DECEMBER 1999
†
APPLICATION INFORMATION
OUTPUT PULSE DURATION CONSTANT
EXTERNAL CAPACITANCE
vs
vs
SUPPLY VOLTAGE
MULTIPLIER FACTOR
0.001
1.20
1.15
For Capacitor Values of
0.001 µF or Greater, K = 1.0
(K is Independent of R)
R
= 10 kΩ
= 25°C
T
T
A
w
t
= K × C × R
T T
1.10
1.05
1.00
0.95
0.90
C
= 1000 pF
T
0.0001
C
= 0.01 µF
= 0.1 µF
T
C
T
T
V
= 25°C
A
0.00001
= 5 V
CC
1.5
2
2.5
V
3
3.5
4
4.5
5
5.5
6
1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50
Multiplier Factor – K
– Supply Voltage – V
CC
Figure 6
Figure 7
DISTRIBUTION OF UNITS
vs
OUTPUT PULSE DURATION
V
= 5 V
CC
T
= 25°C
= 50 pF
= 10 kΩ
A
C
R
T
T
Mean = 856 ns
Median = 856 ns
Std. Dev. = 3.5 ns
–3 Std. Dev.
99% of Data Units
+3 Std. Dev.
Median
t
– Output Pulse Duration
w
Figure 8
†
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
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Copyright 1999, Texas Instruments Incorporated
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