74HC221 datasheet(4/15 Pages) PHILIPS

Part #	74HC221

Description	Dual non-retriggerable monostable multivibrator with reset

PDF	15 Pages

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Manufacturer	PHILIPS [NXP Semiconductors]

Direct Link	http://www.nxp.com

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4 / 15 page

December 1990

Philips Semiconductors

Product speciﬁcation

Dual non-retriggerable monostable

multivibrator with reset

74HC/HCT221

Fig.4 Functional diagram.

FUNCTION TABLE

Notes

1. H = HIGH voltage level

L = LOW voltage level

X = don’t care

↑ = LOW-to-HIGH level

↓ = HIGH-to-LOW level

= one HIGH-level output pulse

= one LOW-level output pulse

2. If the monostable was triggered before this condition

was established the pulse will continue as

programmed.

3. For this combination the reset input must be LOW and

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.

INPUTS

OUTPUTS

nRD

nAnB

L (2)

H (2)

L (2)

H (2)

↑

↓

↑

(3)

74HC221 Datasheet(PDF) 4 Page - NXP Semiconductors