Rev.2.00, Feb.18.2005, page 1 of 6

HD74LS640

Octal Bus Transceivers (inverted 3-state outputs)

REJ03D0487–0200

Rev.2.00

Feb.18.2005

This octal bus transceivers is designed for asynchronous two-way communication between data buses. The device

transmit data from the A bus to the B bus or from the B bus to the A bus depending upon the level at the direction

control (DIR) input. The enable input (

G) can be used to disable the device so that the buses are effectively isolated.

Features

• Ordering Information

Part Name

Package Type

Package Code

(Previous Code)

Package

Abbreviation

Taping Abbreviation

(Quantity)

HD74LS640P

DILP-20 pin

PRDP0020AC-B

(DP-20NEV)

P

—

HD74LS640FPEL

SOP-20 pin (JEITA)

PRSP0020DD-B

(FP-20DAV)

FP

EL (2,000 pcs/reel)

Note:

Please consult the sales office for the above package availability.

Pin Arrangement

(Top view)

GND

DIR

1A

2A

3A

4A

5A

6A

7A

8A

Enable

G

2B

1B

3B

5B

4B

6B

8B

7B

20

17

18

19

15

16

1

2

3

4

5

6

7

14

8

9

10

11

12

13

Function Table

Enable

Direction Control

G

DIR

Operation

L

L

B data to A bus

L

H

A data to B bus

H

X

Isolation

Note:

H; high level, L; low level, X; irrelevant