SN74LS221
(TOP VIEW)
1 R
ext/
1
V
CC
C
ext
C
ext
16
15
14
Q
Q
CLR
1Q
13
2Q
12
2
CLR
11
2B
10
2A
9
CLR
Q
Q
4
1Q
5
2Q
6
2
C
ext
8
7
2 R
ext
/ GND
C
ext
1
1A
2
1B
3
1
CLR
Positive logic: Low input to clear resets Q low and
Positive logic:
Q high regardless of dc levels at A
Positive logic:
or B inputs.
V
CC
R
ext
+
C
ext
R/C
FUNCTION TABLE
(EACH MONOSTABLE)
INPUTS
CLEAR
L
X
X
H
H
*
°
OUTPUTS
B
X
X
L
°
H
H
Q
L
L
L
Q
H
H
H
A
X
H
X
L
±
L
*See operational notes — Pulse Trigger Modes
TYPE
SN74LS221
TYPICAL
POWER
DISSIPATION
23 mW
MAXIMUM
OUTPUT PULSE
LENGTH
70 s
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2