General Description
This 8-bit register features totem-pole 3-STATE outputs designed specifically for driving highly-capacitive or relatively low-impedance loads. The high-impedance state and increased high-logic-level drive provides this register with the capability of being connected directly to and driving the bus lines in a bus-organized system without need for interface or pull-up components. It is particularly attractive for implementing buffer registers, I/O ports, bidirectional bus drivers, and working registers.
The eight flip-flops of the DM74ALS374 are edge-triggered D-type flip-flops. On the positive transition of the clock, the Q outputs will be set to the logic states that were set up at
the D inputs.
A buffered output control 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 output control does not affect the internal operation of the flip-flops. That is, the old data can be retained or new data can be entered even while the outputs are OFF.
FEATUREs
■ Switching specifications at 50 pF
■ Switching specifications guaranteed over full
temperature and VCC range
■ Advanced oxide-isolated, ion-implanted Schottky TTL process
■ Functionally and pin-for-pin compatible with LS TTL counterpart
■ Improved AC performance over DM74LS374 at approximately half the power
■ 3-STATE buffer-type outputs drive bus lines directly