SN54BCT640, SN74BCT640
OCTAL BUS TRANSCEIVERS
WITH 3-STATE OUTPUTS
SCBS025C – SEPTEMBER 1988 – REVISED APRIL 1994
Copyright  1994, Texas Instruments Incorporated
2–1POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
• State-of-the-Art BiCMOS Design
Substantially Reduces Standby Current
• Outputs Have Undershoot-Protection
Circuitry
• Power-Up High-Impedance State
• Buffered Control Inputs to Reduce DC
Loading Effects
• ESD Protection Exceeds 2000 V
Per MIL-STD-883C, Method 3015
• Package Options Include Plastic
Small-Outline (DW) Packages, Ceramic
Chip Carriers (FK) and Flatpacks (W), and
Plastic and Ceramic 300-mil DIPs (J, N)

description
The ′BCT640 bus transceiver is designed for
asynchronous communication between data
buses. These devices 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 output-enable (OE) input can be
used to disable the device so that the buses are
effectively isolated.
The SN54BCT640 is characterized for operation
over the full military temperature range of –55°C
to 125°C. The SN74BCT640 is characterized for
operation from 0°C to 70°C.
FUNCTION TABLE
INPUTS
OPERATION
OE DIR
L L B data to A bus
L HA data to B bus
H X Isolation
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
DIR
A1
A2
A3
A4
A5
A6
A7
A8
GND
V
CC
OE
B1
B2
B3
B4
B5
B6
B7
B8
SN54BCT640 ...J OR W PACKAGE
SN74BCT640 . . . DW OR N PACKAGE
(TOP VIEW)
3212019
9 10 11 12 13
4
5
6
7
8
18
17
16
15
14
B1
B2
B3
B4
B5
A3
A4
A5
A6
A7
SN54BCT640 . . . FK PACKAGE
(TOP VIEW)
A2 A1 DIR
B7 B6
OE
A8
GND
B8
V
CC
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.