Datasheet

www.ti.com
DESCRIPTION/ORDERING INFORMATION (CONTINUED)
SN54LVTH162374 , , SN74LVTH162374
3.3-V ABT 16-BIT EDGE-TRIGGERED D-TYPE FLIP-FLOPS
WITH 3-STATE OUTPUTS
SCBS262M – JULY 1993 – REVISED NOVEMBER 2006
The 'LVTH162374 devices are 16-bit edge-triggered D-type flip-flops with 3-state outputs designed for
low-voltage (3.3-V) V
CC
operation, but with the capability to provide a TTL interface to a 5-V system
environment. They are particularly suitable for implementing buffer registers, I/O ports, bidirectional bus drivers,
and working registers.
These devices can be used as two 8-bit flip-flops or one 16-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 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 a high-impedance state. In the high-impedance state, the outputs neither load nor drive the
bus lines significantly. The high-impedance state and the increased drive provide the capability to drive bus lines
without need for 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.
The outputs, which are designed to source or sink up to 12 mA, include equivalent 22- Ω series resistors to
reduce overshoot and undershoot.
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.
When V
CC
is between 0 and 1.5 V, the devices are 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.
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.
2
Submit Documentation Feedback