Datasheet

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DESCRIPTION/ORDERING INFORMATION (CONTINUED)
SN74LVTH32374
3.3-V ABT 32-BIT EDGE-TRIGGERED D-TYPE FLIP-FLOP
WITH 3-STATE OUTPUTS
SCBS752D – SEPTEMBER 2000 – REVISED AUGUST 2007
This device can be used as four 8-bit flip-flops, two 16-bit flip-flops, or one 32-bit flip-flop. On the positive
transition of the clock (CLK), the Q outputs of the flip-flop take on the logic levels set up at the data (D) inputs.
A buffered output-enable ( OE) input can be used to place the eight outputs in either a normal logic state (high or
low logic levels) or the high-impedance state. In the high-impedance state, the outputs neither load nor drive the
bus lines significantly. The high-impedance state and increased drive provide the capability to drive bus lines
without interface or pullup components.
OE does not affect internal operations of the flip-flop. Old data can be retained or new data can be entered while
the outputs are in the high-impedance state.
When V
CC
is between 0 and 1.5 V, the device is in the high-impedance state during power up or power down.
However, to ensure the high-impedance state above 1.5 V, 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 hot-insertion applications using I
off
and power-up 3-state. The I
off
circuitry
disables the outputs, preventing damaging current backflow through the device when it is 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.
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.
FUNCTION TABLE
(each 8-bit flip-flop)
INPUTS
OUTPUT
Q
OE CLK D
L ↑ H H
L ↑ L L
L H or L X Q
0
H X X Z
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