2

Functional Diagram

9

6

7

10

Q0

Q1

Q2

Q3

4

11

15

1

3

D0

D2

WE

RE

514

13

RA1

RA0

WA0

WA1

12

2

D1

D3

WRITE MODE SELECT TABLE

OPERATING

MODE

INPUTS

INTERNAL

LATCHES

(NOTE 1)

WE

Write Data

L

L

L

LH

H

Data Latched

H

X

No Change

NOTE:

1. The Write Address (WA0 and WA1) to the “internal latches” must

be stable while WE is LOW for conventional operation.

READ MODE SELECT TABLE

OPERATING

MODE

INPUTS

OUTPUT

RE

INTERNAL

LATCHES

(NOTE 2)

Read

L

L

L

LH

H

Disabled

H

X

(Z)

NOTE:

2. The selection of the “internal latches” by Read Address (RA0 and

RA1) are not constrained by WE or RE operation.

H = High Voltage Level

L = Low Voltage Level

X= Don’t Care

Z = High Impedance “Off” State

CD54HC670, CD74HC670, CD74HCT670

CD54HC670, CD74HC670, CD74HCT670