Philips Semiconductors

Product specification

74ALVT16821

2.5V/3.3V 20-bit bus-interface D-type flip-flop;

positive-edge trigger (3-State)

1998 Feb 13

4

PIN DESCRIPTION

PIN NUMBER

SYMBOL

FUNCTION

56, 54, 52, 51, 49,

48, 47, 45, 44, 43,

42, 41, 40, 38, 37,

36, 34, 33, 31, 30

1D0 - 1D9

2D0 - 2D9

Data inputs

2, 3, 5, 6, 8, 9, 10,

12, 13, 14,

15, 16, 17, 19, 20,

21, 23, 24, 26, 27

1Q0 - 1Q9

2Q0 - 2Q9

Data outputs

1, 28

1OE, 2OE

Output enable inputs

(active-Low)

56, 29

1CP, 2CP

Clock pulse inputs

(active rising edge)

4, 11, 18, 25, 32,

39, 46, 53

GND

Ground (0V)

7, 22, 35, 50

Positive supply

voltage

FUNCTION TABLE

INPUTS

INTERNAL

OUTPUTS

OPERATING

nOE

nCP

nDx

INTERNAL

REGISTER

nQ0 - nQ9

OPERATING

MODE

L

L

↑

↑

l

h

L

H

L

H

Load and read

register

L

↑

X

NC

NC

Hold

H

H

↑

↑

X

Dn

NC

Dn

Z

Z

Disable

outputs

H = High voltage level

h

= High voltage level one set-up time prior to the Low-to-High

clock transition

L

= Low voltage level

l

= Low voltage level one set-up time prior to the Low-to-High

clock transition

NC= No change

X = Don’t care

Z = High impedance “off” state

↑ = Low to High clock transition

↑ = Not a Low-to-High clock transition

LOGIC DIAGRAM

CP Q

D

nD0

nQ0

nCP

nOE

CP Q

D

nD1

nQ1

CP Q

D

nD2

nQ2

CP Q

D

nD3

nQ3

CP Q

D

nD4

nQ4

CP Q

D

nD5

nQ5

CP Q

D

nD6

nQ6

CP Q

D

nD7

nQ7

CP Q

D

nD8

nQ8

CP Q

D

nD9

nQ9

SH00004