SN54221, SN54LS221, SN74221, SN74LS221
DUAL MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SDLS213A – DECEMBER 1983 – REVISED FEBRUAR Y 1998
1
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
D
Dual Versions of Highly Stable SN54121
and SN74121 One Shots
D
SN54221 and SN74221 Demonstrate
Electrical and Switching Characteristics
That Are Virtually Identical to the SN54121
and SN74121 One Shots
D
Pinout Is Identical to the SN54123,
SN74123, SN54LS123, and SN74LS123
D
Overriding Clear Terminates Output Pulse
D
Package Options Include Plastic
Small-Outline (D), Shrink Small-Outline
(DB) Packages, Ceramic Chip Carriers (FK)
and Flat Packs (W), and Standard Plastic
(N) and Ceramic (J) 300-mil DIPs
TYPE
MAXIMUM
OUTPUT
PULSE
LENGTH(S)
SN54221 21
SN74221 28
SN54LS221 49
SN74LS221 70
description
The ’221 and ’LS221 devices are monolithic dual
multivibrators with performance characteristics
virtually identical to those of the ’121 devices.
Each multivibrator features a negative-transition-
triggered input and a positive-transition-triggered
input, either of which can be used as an inhibit
input.
Pulse triggering occurs at a particular voltage level and is not directly related to the transition time of the input
pulse. Schmitt-trigger input circuitry (TTL hysteresis) for B input allows jitter-free triggering from inputs with
transition rates as slow as 1 V/s, providing the circuit with excellent noise immunity, typically of 1.2 V. A high
immunity to VCC noise, typically of 1.5 V, is also provided by internal latching circuitry.
Once fired, 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 can be of any duration
relative to the output pulse. Output pulse length can be varied from 35 ns to the maximums shown in the above
table by choosing appropriate timing components. With Rext = 2 kΩ and Cext = 0, an output pulse typically of
30 ns is achieved, which can be used as a dc-triggered reset signal. Output rise and fall times are TTL
compatible and independent of pulse length. T ypical triggering and clearing sequences are shown as a part of
the switching characteristics waveforms.
Pulse-width stability is achieved through internal compensation and is virtually independent of VCC and
temperature. In most applications, pulse stability is limited only by the accuracy of external timing components.
Copyright 1998, Texas Instruments Incorporated
PRODUCTION DATA information is 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.
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.
3212019
910 11 12 13
4
5
6
7
8
18
17
16
15
14
1Cext
1Q
NC
2Q
2CLR
1CLR
1Q
NC
2Q
2Cext
1B
1A
NC
2A
2B V
1R
extGND
NC
1A
1B
1CLR
1Q
2Q
2Cext
2Rext/Cext
GND
VCC
1Rext/Cext
1Cext
1Q
2Q
2CLR
2B
2A
SN54221, SN54LS221 ...J OR W PACKAGE
SN74221 ...N PACKAGE
SN74LS221 . . . D, DB, OR N PACKAGE
(TOP VIEW)
SN54LS221 . . . FK PACKAGE
(TOP VIEW)
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
CC
ext/Cext
2R /Cext
NC – No internal connection
On products compliant to MIL-PRF-38535, all parameters are tested
unless otherwise noted. On all other products, production
processing does not necessarily include testing of all parameters.
SN54221, SN54LS221, SN74221, SN74LS221
DUAL MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SDLS213A – DECEMBER 1983 – REVISED FEBRUAR Y 1998
2POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
description (continued)
Jitter-free operation is maintained over the full temperature and VCC ranges for more than six decades of timing
capacitance (10 pF to 10 µF) and more than one decade of timing resistance (2 kΩ to 30 kΩ for the SN54221,
2 kΩ to 40 kΩ for the SN74221, 2 kΩ to 70 kΩ for the SN54LS221, and 2 kΩ to 100 kΩ for the SN74LS221).
Throughout these ranges, pulse width is defined by the relationship: tw(out) = CextRext In2 ≈ 0.7 CextRext. In
circuits where pulse cutoff is not critical, timing capacitance up to 1000 µF and timing resistance as low as 1.4 kΩ
can be used. Also, the range of jitter-free output pulse widths is extended if VCC is held to 5 V and free-air
temperature is 25°C. Duty cycles as high as 90% are achieved when using maximum recommended RT. Higher
duty cycles are available if a certain amount of pulse-width jitter is allowed.
The variance in output pulse width from device to device typically is less than ±0.5% for given external timing
components. An example of this distribution for the ’221 is shown in Figure 3. Variations in output pulse width
versus supply voltage and temperature for the ’221 are shown in Figures 4 and 5, respectively.
Pin assignments for these devices are identical to those of the SN54123/SN74123 or SN54LS123/SN74LS123
so that the ’221 or ’LS221 devices can be substituted for those products in systems not using the retrigger by
merely changing the value of Rext and/or Cext; however, the polarity of the capacitor must be changed.
The SN54221 and SN54LS221 are characterized for operation over the full military temperature range of –55°C
to 125°C. The SN74221 and SN74LS221 are characterized for operation from 0°C to 70°C.
FUNCTION TABLE
(each monostable multivibrator)
INPUTS OUTPUTS
CLR A B Q Q
L X X L H
XHXLH
XXLLH
H L ↑††
H↓H††
↑‡L H † †
†Pulsed-output patterns are tested during
AC switching at 25°C with Rext = 2 kΩ, and
Cext = 80 pF.
‡This condition is true only if the output of
the latch formed by the two NAND gates
has been conditioned to the logic 1 state
prior to CLR going high. This latch is
conditioned by taking either A high or
B low while CLR is inactive (high).
SN54221, SN54LS221, SN74221, SN74LS221
DUAL MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SDLS213A – DECEMBER 1983 – REVISED FEBRUAR Y 1998
3
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
logic symbol†
1
1A 2
1B 1Q
13
4
R
3
CX
14
RX/CX
15
9
2A 10
2B
R
11
CX
6
RX/CX
7
2Q
5
12
&
&
1
1
1Q
2Q
1CLR
1Cext
1Rext/Cext
2CLR
2Cext
2Rext/Cext
†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, and W packages.
timing component connections
VCC
Rext
To Cext
Terminal To Rext/Cext
Terminal
NOTE: Due to the internal circuit, the Rext/Cext terminal is never more positive than the Cext terminal.
SN54221, SN54LS221, SN74221, SN74LS221
DUAL MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SDLS213A – DECEMBER 1983 – REVISED FEBRUAR Y 1998
4POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
schematics of inputs and outputs
VCC
Req
Input
VCC
100 Ω NOM
Output
EQUIVALENT OF EACH INPUT TYPICAL OF ALL OUTPUTS
SN54/74221
SN54/74LS221
EQUIVALENT OF EACH INPUT TYPICAL OF ALL OUTPUTS
VCC
Req
Input
VCC
Output
120 Ω NOM
A Input: Req = 4 kΩ NOM
B, CLR Input: Req = 2 kΩ NOM
A Input: Req = 25 kΩ NOM
B Input: Req = 15.4 kΩ NOM
CLR: Req = 12.5 kΩ NOM
SN54221, SN54LS221, SN74221, SN74LS221
DUAL MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SDLS213A – DECEMBER 1983 – REVISED FEBRUAR Y 1998
5
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)†
Supply voltage range, VCC 7 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input voltage range, VI (see Note 1): ’LS221 7 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
’221 5.5 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Package thermal impedance, θJA (see Note 2): D package 113°C/W. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DB package 131°C/W. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
N package 78°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 af fect device reliability.
NOTES: 1. The input and output negative-voltage ratings may be exceeded if the input and output clamp-current ratings are observed.
2. The package thermal impedance is calculated in accordance with JESD 51, except for through-hole packages, which use a trace
length of zero
recommended operating conditions
SN54221 SN74221
UNIT
MIN NOM MAX MIN NOM MAX
UNIT
VCC Supply voltage 4.5 5 5.5 4.75 5 5.25 V
VIH High-level input voltage A input 2 2 V
VIL Low-level input voltage A input 0.8 0.8 V
IOH High-level output current –800 –800 µA
IOL Low-level output current 16 16 mA
∆v/∆t
Rise or fall of in
p
ut
p
ulse rate
B input 1* 1 V/s
∆
v
/∆t
Rise
or
fall
of
inp
u
t
p
u
lse
rate
A input 1* 1 V/µs
TAOperating free-air temperature –55 125 0 70 °C
∗ On products compliant to MIL-PRF-38535, this parameter is not production tested.
SN54221, SN54LS221, SN74221, SN74LS221
DUAL MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SDLS213A – DECEMBER 1983 – REVISED FEBRUAR Y 1998
6POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
PARAMETER
TEST CONDITIONS†
SN54221 SN74221
UNIT
PARAMETER
TEST
CONDITIONS†
MIN TYP‡MAX MIN TYP‡MAX
UNIT
VT+ Positive-going threshold voltage,
B input VCC = MIN 1.55 2* 1.55 2 V
VT– Negative-going threshold voltage,
B input VCC = MIN 0.8* 1.35 0.8 1.35 V
VIK VCC = MIN, II = –12 mA –1.5 –1.5 V
VOH VCC = MIN, IOH = –800 µA 2.4 3.4 2.4 3.4 V
VOL VCC = MIN, IOL = 16 mA 0.2 0.4 0.2 0.4 V
IIVCC = MAX, VI = 5.5 V 1 1 mA
I
A input
VCC = MAX
VI=24V
40 40
µA
I
IH CLR, B input
V
CC =
MAX
,
V
I =
2
.
4
V
80 80 µ
A
I
A input
VCC = MAX
VI=04V
–1.6 –1.6
mA
I
IL CLR, B input
V
CC =
MAX
,
V
I =
0
.
4
V
–3.2 –3.2
mA
IOS§VCC = MAX –20 –55 –18 –55 mA
ICC
Quiescent
VCC = MAX
26 50* 26 50
mA
I
CC Triggered
V
CC =
MAX
46 80* 46 80
mA
∗ On products compliant to MIL-PRF-38535, this parameter is not production tested.
†For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions.
‡All typical values are at VCC = 5 V, TA = 25°C.
§Not more than one output should be shorted at a time and the duration of the short circuit should not exceed one second.
timing requirements over recommended ranges of supply voltage and operating free-air
temperature
SN54221 SN74221
UNIT
MIN MAX MIN MAX
UNIT
t
A or B input 50 50
ns
t
w
u
u
CLR 20 20
ns
tsu Setup time, inactive-state¶ CLR 15 15 ns
Rext External timing resistance 1.4* 30* 1.4 40 kΩ
Cext External timing capacitance 0* 1000* 0 1000 µF
p
Rext = 2 kΩ67% 67%
u
u
u
y
y
Rext = MAX Rext 90% 90%
∗ On products compliant to MIL-PRF-38535, this parameter is not production tested.
Inactive-state setup time is also referred to as recovery time.
SN54221, SN54LS221, SN74221, SN74LS221
DUAL MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SDLS213A – DECEMBER 1983 – REVISED FEBRUAR Y 1998
7
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
switching characteristics VCC = 5 V, RL = 400 Ω, TA = 25
_
C (see Figures 1 and 2)
PARAMETER
FROM TO
TEST CONDITIONS
SN54221 SN74221
UNIT
PARAMETER
(INPUT) (OUTPUT)
TEST
CONDITIONS
MIN TYP MAX MIN TYP MAX
UNIT
tPLH
A
Q
45 70 45 70
t
PLH B
Q
C80pF
R2kΩ
35 55 35 55
ns
tPHL
A
Q
C
ext =
80
p
F
,
R
ext =
2
kΩ
50 80 50 80
ns
t
PHL B
Q
40 65 40 65
tPHL
CLR
Q
C80pF
R2kΩ
27 27
ns
tPLH
CLR
Q
C
ext =
80
p
F
,
R
ext =
2
kΩ
40 40
ns
Cext = 80 pF, Rext = 2 kΩ70 110 150 70 110 150
t
AorB
QorQ
Cext = 0, Rext = 2 kΩ17 30 50 17 30 50 ns
t
w
A
or
B
Q
or
Q
Cext = 100 pF, Rext = 10 kΩ650 700 750 650 700 750
Cext = 1 µF, Rext = 10 kΩ6.5* 7 7.5* 6.5 7 7.5 ms
∗ On products compliant to MIL-PRF-38535, this parameter is not production tested.
recommended operating conditions
SN54LS221 SN74LS221
UNIT
MIN NOM MAX MIN NOM MAX
UNIT
VCC Supply voltage 4.5 5 5.5 4.75 5 5.25 V
VIH High-level input voltage A input 2 2 V
VIL Low-level input voltage A input 0.7 0.8 V
IOH High-level output current –400 –400 µA
IOL Low-level output current 4 8 mA
∆v/∆t
Rise or fall of in
p
ut
p
ulse rate
B input 1*1 V/s
∆
v
/∆t
Rise
or
fall
of
inp
u
t
p
u
lse
rate
A input 1*1 V/µs
TAOperating free-air temperature –55 125 0 70 °C
∗ On products compliant to MIL-PRF-38535, this parameter is not production tested.
SN54221, SN54LS221, SN74221, SN74LS221
DUAL MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SDLS213A – DECEMBER 1983 – REVISED FEBRUAR Y 1998
8POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
PARAMETER
TEST CONDITIONS†
SN54LS221 SN74LS221
UNIT
PARAMETER
TEST
CONDITIONS†
MIN TYP‡MAX MIN TYP‡MAX
UNIT
VT+ Positive-going threshold voltage,
B input VCC = MIN 1 2* 1 2 V
VT– Negative-going threshold voltage,
B input VCC = MIN 0.7* 0.9 0.8 0.9 V
VIK VCC = MIN, II = –18 mA –1.5 –1.5 V
VOH VCC = MIN, IOH = –400 µA 2.5 3.4 2.7 3.4 V
VOL
VCC = MIN
IOL = 4 mA 0.25 0.4 0.25 0.4
V
V
OL
V
CC =
MIN
IOL = 8 mA 0.35 0.5
V
IIVCC = MAX, VI = 7 V 0.1 0.1 mA
IIH VCC = MAX, VI = 2.7 V 20 20 µA
I
A input
VCC = MAX
VI=04V
–0.4 –0.4
mA
I
IL CLR, B input
V
CC =
MAX
,
V
I =
0
.
4
V
–0.8 –0.8
mA
IOS§VCC = MAX –20 –100 –20 –100 mA
ICC
Quiescent
VCC = MAX
4.7 11 4.7 11
mA
I
CC Triggered
V
CC =
MAX
19 27* 19 27
mA
∗ On products compliant to MIL-PRF-38535, this parameter is not production tested.
†For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions.
‡All typical values are at VCC = 5 V, TA = 25°C.
§Not more than one output should be shorted at a time and the duration of the short circuit should not exceed one second.
timing requirements over recommended ranges of supply voltage and operating free-air
temperature
SN54LS221 SN74LS221
UNIT
MIN MAX MIN MAX
UNIT
t
Pulse duration
A or B 50 50
ns
t
w
P
u
lse
d
u
ration
CLR 40 40
ns
tsu Setup time, inactive stateCLR 15 15 ns
Rext External timing resistance 1.4* 70* 1.4 100 kΩ
Cext External timing capacitance 0* 1000* 0 1000 µF
Out
p
ut duty cycle
RT = 2 kΩ50% 50%
O
u
tp
u
t
d
u
t
y
c
y
cle
RT = MAX Rext 90% 90%
∗ On products compliant to MIL-PRF-38535, this parameter is not production tested.
Inactive-state setup time is also referred to as recovery time.
SN54221, SN54LS221, SN74221, SN74LS221
DUAL MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SDLS213A – DECEMBER 1983 – REVISED FEBRUAR Y 1998
9
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
switching characteristics VCC = 5 V, RL = 2 kΩ, TA = 25
_
C (see Figures 1 and 2)
PARAMETER
FROM TO
TEST CONDITIONS
SN54LS221 SN74LS221
UNIT
PARAMETER
(INPUT) (OUTPUT)
TEST
CONDITIONS
MIN TYP MAX MIN TYP MAX
UNIT
tPLH
A
Q
45 70 45 70
t
PLH B
Q
C80pF
R2kΩ
35 55 35 55
ns
tPHL
A
Q
C
ext =
80
p
F
,
R
ext =
2
kΩ
50 80 50 80
ns
t
PHL B
Q
40 65 40 65
tPHL
CLR
Q
C80pF
R2kΩ
35 55 35 55
ns
tPLH
CLR
Q
C
ext =
80
p
F
,
R
ext =
2
kΩ
44 65 44 65
ns
Cext = 80 pF, Rext = 2 kΩ70 120 150 70 120 150
t
AorB
QorQ
Cext = 0, Rext = 2 kΩ20 47 70 20 47 70 ns
t
w
A
or
B
Q
or
Q
Cext = 100 pF, Rext = 10 kΩ670 740 810 670 740 810
Cext = 1 µF, Rext = 10 kΩ6* 6.9 7.5* 6 6.9 7.5 ms
∗ On products compliant to MIL-PRF-38535, this parameter is not production tested.
SN54221, SN54LS221, SN74221, SN74LS221
DUAL MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SDLS213A – DECEMBER 1983 – REVISED FEBRUAR Y 1998
10 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
PARAMETER MEASUREMENT INFORMATION
B†
CLR
Q
Q
3 V
3 V
0 V
0 V
VOH
VOH
VOL
VOL
tw
≥ 60 ns
tPLH tPHL
tPHL tPLH
CONDITION 1: TRIGGER FROM B, THEN CLR
B†
CLR
Q
3 V
3 V
0 V
0 V
VOH
VOL
≥ 60 ns
CONDITION 2: TRIGGER FROM B, THEN CLR
B†
CLR
Q
3 V
3 V
0 V
0 V
VOH
VOL
≥ 50 ns
CONDITION 3: CLR OVERRIDING B, THEN TRIGGER FROM B
tsu
≥ 0
tw
Triggered
Not Triggered
†A is low.
Figure 1. Switching Characteristics
SN54221, SN54LS221, SN74221, SN74LS221
DUAL MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SDLS213A – DECEMBER 1983 – REVISED FEBRUAR Y 1998
11
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
PARAMETER MEASUREMENT INFORMATION
B†
CLR
Q
3 V
3 V
0 V
0 V
VOH
VOL
≥ 50 ns
CONDITION 4: TRIGGERING FROM POSITIVE TRANSITION OF CLR
≥ 50 ns
A‡
CLR
Q
Q
3 V
3 V
0 V
0 V
VOH
VOH
VOL
VOL
tw
≥ 60 ns
tPLH tPHL
tPHL tPLH
CONDITION 5: TRIGGER FROM A, THEN CLR
A‡
Q
Q
3 V
0 V
VOH
VOH
VOL
VOL
tw
CONDITION 6: TRIGGER FROM A
tw
†A is low.
‡B and CLR are high.
NOTES: A. Input pulses are supplied by generators having the following characteristics: PRR ≤ 1 MHz, ZO ≈ 50Ω; for SN54/74221, tr ≤ 7 ns,
tf ≤ 7 ns, for SN54/74LS221, tr ≤ 15 ns, tf ≤ 6 ns.
B. All measurements are made between the 1.5-V points of the indicated transitions for the SN54/74221 or between the 1.3-V points
for the SN54/74LS221.
Figure 1. Switching Characteristics (Continued)
SN54221, SN54LS221, SN74221, SN74LS221
DUAL MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SDLS213A – DECEMBER 1983 – REVISED FEBRUAR Y 1998
12 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
PARAMETER MEASUREMENT INFORMATION
tPHL tPLH
tPLH tPHL
3 V
3 V
0 V
0 V
th
tsu
VOLTAGE WAVEFORMS
SETUP AND HOLD TIMES
Timing
Input
Data
Input
High-Level
Pulse
Low-Level
Pulse
tw
VOLTAGE WAVEFORMS
PULSE DURATIONS
Input
Out-of-Phase
Output
3 V
0 V
VOL
VOH
VOH
VOL
In-Phase
Output
VOLTAGE WAVEFORMS
PROPAGATION DELAY TIMES
LOAD CIRCUIT FOR
BI-STATE
TOTEM-POLE OUTPUTS
(see Note B)
VCC
RL
From Output
Under Test CL = 15 pF
(see Note A)
Test
Point
NOTES: A. CL includes probe and jig capacitance.
B. All diodes are 1N3064 or equivalent.
C. In the examples above, the phase relationships between inputs and outputs have been chosen arbitrarily.
D. All input pulses are supplied by generators having the following characteristics: PRR ≤ 1 MHz, ZO ≈ 50 Ω and, for SN54/74221,
tr ≤ 7 ns, tf ≤ 7 ns, for SN54/74LS221, tr ≤ 15 ns, tf ≤ 6 ns.
E. All measurements are made between the 1.5-V points of the indicated transitions for the SN54/74221 or between the 1.3-V points
for the SN54/74LS221.
Figure 2. Load Circuits and Voltage Waveforms
SN54221, SN54LS221, SN74221, SN74LS221
DUAL MONOSTABLE MULTIVIBRATORS
WITH SCHMITT-TRIGGER INPUTS
SDLS213A – DECEMBER 1983 – REVISED FEBRUAR Y 1998
13
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
TYPICAL CHARACTERISTICS (SN54/74221 ONLY)†
Figure 3
Median
Relative Frequency of Occurrence
DISTRIBUTION OF UNITS
FOR
OUTPUT PULSE
tw – Output Pulse
VCC = 5 V
TA = 25°C
Median
+0.5%
Median
+0.5%
Figure 4
0
– 0.5
–14.5 4.75 5
0.5
VARIATION IN OUTPUT PULSE
vs
SUPPLY VOLTAGE
1
5.25 5.5
– Variation in Output Pulse – %∆tw
VCC – Supply Voltage – V
Cext = 60 pF
Rext = 10 kΩ
TA = 25°C
tw ≈ 420 ns
at VCC = 5 V
Figure 5
–25–50–75
0
– 0.5
–1 02550
– Variation in Output Pulse – %
0.5
VARIATION IN OUTPUT PULSE
vs
FREE-AIR TEMPERATURE
1
75 100 125
TA – Free-Air Temperature – °C
∆tw
VCC = 5 V
Cext = 60 pF
Rext = 10 kΩ
tw ≈ 420 ns
at TA = 25°C
OUTPUT PULSE
vs
TIMING RESISTOR VALUE
Figure 6
100 ns
10 ns12 4710
10 ms
1 ms
20 40 70 100
– Output Pulsetw
100 µs
10 µs
1 µs
VCC = 5 V
TA = 25°C
FµCext = 1
FµCext= 0.1
FµCext = 0.01
Cext = 1000 pF
Cext = 100 pF
Cext = 10 pF
See Note A
Rext – Timing Resistor Value – kΩ
†Data for temperatures below 0°C and above 70°C, and for supply voltages below 4.75 V and above 5.25 V are applicable for the SN54221 only .
NOTE A: These values of resistance exceed the maximum recommended for use over the full military temperature range of the SN54221.
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