Datasheet

B1
DIR
5
7
A1
2
V
CCA
V
CCB
B2
6
A2
3
SN74LVC2T45-EP
SCES777C –NOVEMBER 2008–REVISED JULY 2010 www.ti.com
DESCRIPTION/ORDERING INFORMATION (CONTINUED)
The SN74LVC2T45 is designed for asynchronous communication between two data buses. The logic levels of
the direction-control (DIR) input activate either the B-port outputs or the A-port outputs. The device transmits data
from the A bus to the B bus when the B-port outputs are activated, and from the B bus to the A bus when the
A-port outputs are activated. The input circuitry on both A and B ports always is active and must have a logic
HIGH or LOW level applied to prevent excess I
CC
and I
CCZ
.
The SN74LVC2T45 is designed so that the DIR input circuit is supplied by V
CCA
.
This device is fully specified for partial-power-down applications using I
off
. The I
off
circuitry disables the outputs,
preventing damaging current backflow through the device when it is powered down.
The V
CC
isolation feature ensures that if either V
CC
input is at GND, both ports are in the high-impedance state.
NanoFree™ package technology is a major breakthrough in IC packaging concepts, using the die as the
package.
Table 2. FUNCTION TABLE
(1)
(EACH TRANSCEIVER)
INPUT
OPERATION
DIR
L B data to A bus
H A data to B bus
(1) Input circuits of the data I/Os
always are active.
LOGIC DIAGRAM (POSITIVE LOGIC)
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