74hct221 NXP Semiconductors, 74hct221 Datasheet - Page 4

• Manufacturer Part Number: 74hct221
• Description: Dual Non-retriggerable Monostable Multivibrator With Reset
• Manufacturer: NXP Semiconductors

Philips Semiconductors
December 1990
Dual non-retriggerable monostable
multivibrator with reset
Fig.4 Functional diagram.
4
FUNCTION TABLE
Notes
1. H = HIGH voltage level
2. If the monostable was triggered before this condition
3. For this combination the reset input must be LOW and
nR
L = LOW voltage level
X = don’t care
was established the pulse will continue as
programmed.
the following sequence must be used:
pin 1 (or 9) must be set HIGH or pin 2 (or 10) set LOW;
then pin 1 (or 9) must be LOW and pin 2 (or 10) set
HIGH. Now the reset input goes from LOW-to-HIGH
and the device will be triggered.
H
H
L
X
X
= LOW-to-HIGH level
= HIGH-to-LOW level
D
= one HIGH-level output pulse
= one LOW-level output pulse
INPUTS
nA
X
X
H
L
L
nB
X
X
H
H
L
74HC/HCT221
nQ
L
L
L
Product specification
(2)
(2)
OUTPUTS
(3)
nQ
H
H
H
(2)
(2)
(3)