Philips Semiconductors

Product specification

74F640

Octal bus transceiver, inverting (3-State)

2

1989 Nov 27

853–0381 98171

FEATURES

(70

µA in High and Low states)

bus loading

DESCRIPTION

The 74F640 is an octal transceiver featuring inverting 3-State bus

compatible outputs in both transmit and receive directions. The B

port outputs are capable of sinking 64mA and sourcing 15mA,

providing very good capacitive drive characteristics. The device

features an Output Enable (OE) input for easy cascading and

Transmit/Receiver (T/R) input for direction control. The 3-State

outputs, B0–B7, have been designed to prevent output bus loading if

the power is removed from the device.

PIN CONFIGURATION

SF00198

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

T/R

A0

A1

A2

A3

A4

A5

A6

A7

GND

OE

B0

B1

B2

B3

B4

B6

B5

B7

TYPE

TYPICAL

PROPAGATION

DELAY

TYPICAL SUPPLY CURRENT

(TOTAL)

74F640

3.5ns

78mA

ORDERING INFORMATION

DESCRIPTION

COMMERCIAL RANGE

PKG DWG #

20-pin plastic DIP

N74F640N

SOT146-1

20-pin plastic SOL

N74F640D

SOT163-1

INPUT AND OUTPUT LOADING AND FAN-OUT TABLE

PINS

DESCRIPTION

74F(U.L.)

HIGH/LOW

LOAD VALUE

HIGH/LOW

A0 - A7, B0 - B7

Data inputs

3.5/0.115

70

µA/70µA

OE

Output Enable input (active Low)

2.0/0.067

40

µA/40µA

T/R

Transmit/Receive input

2.0/0.067

40

µA/40µA

A0 - A7

A port outputs

150/40

3.0mA/24mA

B0 - B7

B port outputs

750/106.7

15mA/64mA

NOTE: One (1.0) FAST unit load is defined as: 20

µA in the High state and 0.6mA in the Low state.