C0083C0078C0053C0052C0050C0050C0049C0044 C0083C0078C0053C0052C0076C0083C0050C0050C0049C0044 C0083C0078C0055C0052C0050C0050C0049C0044 C0083C0078C0055C0052C0076C0083C0050C0050C0049
C0068C0085C0065C0076 C0077C0079C0078C0079C0083C0084C0065C0066C0076C0069 C0077C0085C0076C0084C0073C0086C0073C0066C0082C0065C0084C0079C0082C0083
C0087C0073C0084C0072 C0083C0067C0072C0077C0073C0084C0084C0262C0084C0082C0073C0071C0071C0069C0082 C0073C0078C0080C0085C0084C0083
SDLS213B − DECEMBER 1983 − REVISED NOVEMBER 2004
1POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
C0068 Dual Versions of Highly Stable SN54121
and SN74121 One Shots
C0068 SN54221 and SN74221 Demonstrate
Electrical and Switching Characteristics
That Are Virtually Identical to the SN54121
and SN74121 One Shots
C0068 Pinout Is Identical to the SN54123,
SN74123, SN54LS123, and SN74LS123
C0068 Overriding Clear Terminates Output Pulse
TYPE
MAXIMUM
OUTPUT
PULSE
LENGTH(S)
SN54221 21
SN74221 28
SN54LS221 49
SN74LS221 70

description/ordering information
The ’221 and ’LS221 devices are 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.
ORDERING INFORMATION
T
A
PACKAGE
†
ORDERABLE
PART NUMBER
TOP-SIDE
MARKING
PDIP − N Tube
SN74221N SN74221N
SN74LS221N SN74LS221N
0°C to 70°C SOIC − D
Tube SN74LS221D
LS221
Tape and reel SN74LS221DR
SOP − NS Tape and reel SN74LS221NSR 74LS221
SSOP − DB Tape and reel SN74LS221DBR LS221
CDIP − J Tube
SNJ54221J SNJ54221J
−55°C to 125°C
SNJ54LS221J SNJ54LS221J
LCCC − FK Tube SNJ54LS221FK SNJ54LS221FK
†
Package drawings, standard packing quantities, thermal data, symbolization, and PCB design guidelines are
available at www.ti.com/sc/package.
Copyright  2004, Texas Instruments IncorporatedC0080C0082C0079C0068C0085C0067C0084C0073C0079C0078 C0068C0065C0084C0065 C0105C0110C0102C0111C0114C0109C0097C0116C0105C0111C0110 C0105C0115 C0099C0117C0114C0114C0101C0110C0116 C0097C0115 C0111C0102 C0112C0117C0098C0108C0105C0099C0097C0116C0105C0111C0110 C0100C0097C0116C0101C0046
C0080C0114C0111C0100C0117C0099C0116C0115 C0099C0111C0110C0102C0111C0114C0109 C0116C0111 C0115C0112C0101C0099C0105C0102C0105C0099C0097C0116C0105C0111C0110C0115 C0112C0101C0114 C0116C0104C0101 C0116C0101C0114C0109C0115 C0111C0102 C0084C0101C0120C0097C0115 C0073C0110C0115C0116C0114C0117C0109C0101C0110C0116C0115
C0115C0116C0097C0110C0100C0097C0114C0100 C0119C0097C0114C0114C0097C0110C0116C0121C0046 C0080C0114C0111C0100C0117C0099C0116C0105C0111C0110 C0112C0114C0111C0099C0101C0115C0115C0105C0110C0103 C0100C0111C0101C0115 C0110C0111C0116 C0110C0101C0099C0101C0115C0115C0097C0114C0105C0108C0121 C0105C0110C0099C0108C0117C0100C0101
C0116C0101C0115C0116C0105C0110C0103 C0111C0102 C0097C0108C0108 C0112C0097C0114C0097C0109C0101C0116C0101C0114C0115C0046
3212019
9 10 11 12 13
4
5
6
7
8
18
17
16
15
14
1C
ext
1Q
NC
2Q
2CLR
1CLR
1Q
NC
2Q
2C
ext
1B 1A NC
2A 2B
V 1R
ext
GND
NC
1A
1B
1CLR
1Q
2Q
2C
ext
2R
ext
/C
ext
GND
V
CC
1R
ext
/C
ext
1C
ext
1Q
2Q
2CLR
2B
2A
SN54221, SN54LS221 ...J PACKAGE
SN74221 ...N PACKAGE
SN74LS221 . . . D, DB, N, OR NS 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
/C
ext
2R
/C
ext
NC − No internal connection
C0079C0110 C0112C0114C0111C0100C0117C0099C0116C0115 C0099C0111C0109C0112C0108C0105C0097C0110C0116 C0116C0111 C0077C0073C0076C0262C0080C0082C0070C0262C0051C0056C0053C0051C0053C0044 C0097C0108C0108 C0112C0097C0114C0097C0109C0101C0116C0101C0114C0115 C0097C0114C0101 C0116C0101C0115C0116C0101C0100
C0117C0110C0108C0101C0115C0115 C0111C0116C0104C0101C0114C0119C0105C0115C0101 C0110C0111C0116C0101C0100C0046 C0079C0110 C0097C0108C0108 C0111C0116C0104C0101C0114 C0112C0114C0111C0100C0117C0099C0116C0115C0044 C0112C0114C0111C0100C0117C0099C0116C0105C0111C0110
C0112C0114C0111C0099C0101C0115C0115C0105C0110C0103 C0100C0111C0101C0115 C0110C0111C0116 C0110C0101C0099C0101C0115C0115C0097C0114C0105C0108C0121 C0105C0110C0099C0108C0117C0100C0101 C0116C0101C0115C0116C0105C0110C0103 C0111C0102 C0097C0108C0108 C0112C0097C0114C0097C0109C0101C0116C0101C0114C0115C0046
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.