Datasheet

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DESCRIPTION/ORDERING INFORMATION (CONTINUED)
GQN OR ZQN PACKAGE
(TOP VIEW)
1 2 3 4
A
B
C
D
E
SN74LVC244A
OCTAL BUFFER/DRIVER
WITH 3-STATE OUTPUTS
SCAS414X – NOVEMBER 1992 – REVISED MARCH 2005
The SN74LVC244A is organized as two 4-bit line drivers with separate output-enable ( OE) inputs. When OE is
low, the device passes data from the A inputs to the Y outputs. When OE is high, the outputs are in the
high-impedance state.
Inputs can be driven from either 3.3-V or 5-V devices. This feature allows the use of this device as a translator in
a mixed 3.3-V/5-V system environment.
To ensure the high-impedance state during power up or power down, OE should be tied to V
CC
through a pullup
resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver.
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.
TERMINAL ASSIGNMENTS
1 2 3 4
A 1A1 1 OE V
CC
2 OE
B 1A2 2A4 2Y4 1Y1
C 1A3 2Y3 2A3 1Y2
D 1A4 2A2 2Y2 1Y3
E GND 2Y1 2A1 1Y4
FUNCTION TABLE
(EACH BUFFER)
INPUTS
OUTPUT
Y
OE A
L H H
L L L
H X Z
2