The SN74F543 octal transceiver contains two sets of D-type latches
for temporary storage of data flowing in either direction. 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 outputs
are characterized to sink 24 mA while the B outputs are characterized
to sink 64 mA.
The A-to-B enable ()
input must be low in order to enter data from A or to output data
from B. Having low and low makes the A-to-B latches
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.
The SN74F543 is available in TI's shrink small-outline package
(DB), which provides the same I/O pin count and functionality of
standard small-outline packages in less than half the
The SN74F543 is characterized for operation from 0°C to
A-to-B data flow is shown; B-to-A flow control is the same
except that it uses ,
, and .
Output level before the indicated steady-state input
conditions were established.