SN74AS1821

This SN74AS1821 10-bit flip-flop device features three-state outputs designed specifically for driving highly capacitive or relatively low-impedance loads. It is particularly suitable for implementing wider buffer registers, I/O ports, bidirectional bus drivers with parity, and working registers. The ten flip-flops are edge-triggered D-type flip-flops. On the positive transition of the clock, the Q outputs on the 'AS1821 will be true.

A SN74AS1821 buffered output-control input can be used to place the ten outputs in either a normal logic state (high or low levels) or a high-impedance state. In the SN74AS1821 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 the bus lines in a bus-organized system without need for interface or pull-up components. The output control (OC) does not affect the internal operation of th flipflops. Old data can be retained or new data can be entered while the outputs are in the high-impedance state.

The SN74AS1821 is characterized for operation from 0°C to 70°C.