The 'LVT16543 are 16-bit registered transceivers designed for
low-voltage (3.3-V) VCC operation, but with the capability
to provide a TTL interface to a 5-V system environment. These devices
can be used as two 8-bit transceivers or one 16-bit transceiver.
Separate latch-enable (or
) and
output-enable ( or ) inputs are provided for each
register to permit independent control in either direction of data
flow.
The A-to-B enable ()
input must be low in order to enter data from A or to output data
from B. If is low and
is low, the
A-to-B latches are transparent; a subsequent low-to-high transition
of puts the A
latches in the storage mode. With and both low, the
3-state B outputs are active and reflect the data present at the
output of the A latches. Data flow from B to A is similar but
requires using the ,, and inputs.
Active bus-hold circuitry is provided to hold unused or floating
data inputs at a valid logic level.
To ensure the high-impedance state during power up or power down,
should be tied
to VCC through a pullup resistor; the minimum value of the
resistor is determined by the current-sinking capability of the
driver.
The SN74LVT16543 is available in TI's shrink small-outline (DL)
and thin shrink small-outline (DGG) packages, which provide twice the
I/O pin count and functionality of standard small-outline packages in
the same printed-circuit-board area.
The SN54LVT16543 is characterized for operation over the full
military temperature range of -55°C to 125°C. The
SN74LVT16543 is characterized for operation from -40°C to
85°C.