These octal transparent D-type latches with 3-state outputs are
designed specifically for driving highly capacitive or relatively
low-impedance loads. They are particularly suitable for implementing
buffer registers, I/O ports, bidirectional bus drivers, and working
registers.
When the latch-enable (LE) input is high, the Q\ outputs follow
the complements of the data (D) inputs. When LE is taken low, the Q\
outputs are latched at the inverse of the levels at the D inputs.
A buffered output-enable () 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
increased drive provide the capability to drive bus lines without
need for interface or pullup components.
does not affect
the internal operations of the latches. Previously stored data can be
retained or new data can be entered while the outputs are in the
high-impedance state.
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 SN54ABT533 is characterized for operation over the full
military temperature range of -55°C to 125°C. The
SN74ABT533A is characterized for operation from -40°C to
85°C.
These octal transparent D-type latches with 3-state outputs are
designed specifically for driving highly capacitive or relatively
low-impedance loads. They are particularly suitable for implementing
buffer registers, I/O ports, bidirectional bus drivers, and working
registers.
When the latch-enable (LE) input is high, the Q\ outputs follow
the complements of the data (D) inputs. When LE is taken low, the Q\
outputs are latched at the inverse of the levels at the D inputs.
A buffered output-enable () 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
increased drive provide the capability to drive bus lines without
need for interface or pullup components.
does not affect
the internal operations of the latches. Previously stored data can be
retained or new data can be entered while the outputs are in the
high-impedance state.
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 SN54ABT533 is characterized for operation over the full
military temperature range of -55°C to 125°C. The
SN74ABT533A is characterized for operation from -40°C to
85°C.