Datasheet

SN54ALS245A, SN54AS245, SN74ALS245A, SN74AS245
OCTAL BUS TRANSCEIVERS
WITH 3-STATE OUTPUTS
SDAS272A – NOVEMBER 1994 – REVISED JANUARY 2003
2
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
description/ordering information(continued)
These octal bus transceivers are designed for asynchronous two-way communication between data buses. The
control-function implementation minimizes external timing requirements.
The devices allow data transmission from the A bus to the B bus or from the B bus to the A bus, depending upon
the logic 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 -1 version of the SN74ALS245A is identical to the standard version, except that the recommended
maximum I
OL
is increased to 48 mA. There is no -1 version of the SN54ALS245A.
FUNCTION TABLE
INPUTS
OPERATION
OE DIR
OPERATION
L L B data to A bus
L H A data to B bus
H X Isolation
logic diagram, each gate (positive logic)
DIR
OE
A1
B1
1
2
18
19
To Seven Other Channels
absolute maximum ratings over operating free-air temperature range (SN54ALS245A,
SN74ALS245A) (unless otherwise noted)
†
Supply voltage, V
CC
7 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input voltage, V
I
: All inputs 7 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
I/O ports 5.5 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Package thermal impedance, θ
JA
(see Note 1): DB package 70°C/W. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DW package 58°C/W. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
N package 69°C/W. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
NS package 60°C/W. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Storage temperature range –65°C to 150°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
†
Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and
functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not
implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
NOTE 1: The package thermal impedance is calculated in accordance with JESD 51-7.