
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
L
DIR
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
Input voltage, V
I
: All inputs
7 V
7 V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
I/O ports
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Package thermal impedance,
θ
JA
(see Note 1): DB package
DW package
N package
NS package
Storage temperature range
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.5 V
70
°
C/W
58
°
C/W
69
°
C/W
60
°
C/W
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
–
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.