2

Functional Diagram

TRUTH TABLE

INPUTS

OUTPUTS

AB

RQ

Q

HXH

L

H

XL

H

L

H

L

↑

H

↓

HH

XX

L

L

H

LH

↑

(Note 3)

(Note 3)

H = High Voltage Level, L = Low Voltage Level, X = Irrelevant,

↑ = Transition from

Low to High Level, ↓ = Transition from High to Low Level,

= One High Level

Pulse,

= One Low Level Pulse

NOTE:

1. 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.

2R

11

2A

9

10

5

12

2Q

2Q

2B

MONO 2

67

1R

3

1A

2

1

13

4

1Q

1Q

1B

MONO 1

14

15

CD54HC221, CD74HC221, CD74HCT221