Philips Semiconductors

Product specification

74F647/74F649

Octal transceivers/registers (open-collector)

74F647 Octal Transceiver/Register, Non-inverting (Open Collector)

74F649 Octal Transceiver/Register, Inverting (Open Collector)

2

1992 Feb 28

853-0876 05853

FEATURES

(20

µA in High and Low states)

DESCRIPTION

The 74F647 and 74F649 Transceivers/Registers consist of bus

transceiver circuits with open-collector outputs, D-type flip-flops, and

control circuitry arranged for multiplexed transmission of data

directly from the input bus or from the internal registers. Data on the

A or B bus will be clocked into the registers as the appropriate clock

pin goes to a High logic level. Output Enable (OE) and DIR pins are

provided to control the transceiver function. In the transceiver mode,

data present at the high impedance port may be stored in either the

A or B register or both.

The select (SAB, SBA) controls can multiplex stored and real-time

(transparent mode) data. The DIR determines which bus will receive

data when the Output Enable, OE is active Low. In the isolation

mode (Output Enable, OE = High), data from Bus A may be stored

in the B register and/or data from Bus B may be stored in the A

register.

When an output function is disabled, the input function is still

enabled and may be used to store and transmit data. Only one of

the two buses, A or B, may be driven at a time. The following

examples demonstrate the four fundamental bus-management

functions that can be performed with the 74F647 and 74F649.

TYPE

TYPICAL

TYPICAL SUPPLY CURRENT

(TOTAL)

74F647

65MHz

125mA

74F649

65MHz

125mA

ORDERING INFORMATION

DESCRIPTION

COMMERCIAL RANGE

PKG DWG #

24-pin plastic Slim

DIP (300mil)

N74F647N, N74F649N

SOT222-1

24-pin plastic SOL

N74F647D, N74F649D

SOT137-1

PIN CONFIGURATION – 74F647

24

23

22

21

20

19

18

17

16

15

14

13

12

10

11

9

8

7

6

5

4

3

2

1

CPBA

SBA

OE

VCC

GND

B0

B1

B2

B3

B4

B5

B6

B7

A0

A1

A2

A3

A4

A5

A6

A7

CPAB

SAB

DIR

SF01196

PIN CONFIGURATION – 74F649

24

23

22

21

20

19

18

17

16

15

14

13

12

10

11

9

8

7

6

5

4

3

2

1

CPBA

SBA

OE

VCC

GND

B0

B1

B2

B3

B4

B5

B6

B7

A0

A1

A2

A3

A4

A5

A6

A7

CPAB

SAB

DIR

SF01196