Datasheet

SN54LVTH240, SN74LVTH240
3.3-V ABT OCTAL BUFFERS/DRIVERS
WITH 3-STATE OUTPUTS
SCBS679K − DECEMBER 1996 − REVISED SEPTEMBER 2003
2
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
description/ordering information (continued)
These devices are organized as two 4-bit buffer/line drivers with separate output-enable (OE) inputs. When OE
is low, the devices pass data from the A inputs to the Y outputs. When OE is high, the outputs are in the
high-impedance state.
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.
Active bus-hold circuitry holds unused or undriven inputs at a valid logic state. Use of pullup or pulldown resistors
with the bus-hold circuitry is not recommended.
These devices are fully specified for hot-insertion applications using I
off
and power-up 3-state. The I
off
circuitry
disables the outputs, preventing damaging current backflow through the devices when they are powered down.
The power-up 3-state circuitry places the outputs in the high-impedance state during power up and power down,
which prevents driver conflict.
terminal assignments
1234
A 1A1 1OE V
CC
2OE
B 1A2 2A4 2Y4 1Y1
C 1A3 2Y3 2A3 1Y2
D 1A4 2A2 2Y2 1Y3
E GND 2Y1 2A1 1Y4
FUNCTION TABLE
(each 4-bit buffer)
INPUTS
OUTPUT
OE A
OUTPUT
Y
L H L
L LH
H X Z
SN74LVTH240 . . . GQN OR ZQN PACKAGE
(TOP VIEW)
1234
A
B
C
D
E