MM74HC299

This 8-bit TRI-STATE shift/storage register MM74HC299 utilizes advanced silicon-gate CMOS technology. Along with the low power consumption and high noise immunity of standard CMOS integrated circuits, it has the ability to drive 15 LS-TTL loads. This circuit also features operating speeds comparable to the equivalent low power Schottky device.
The MM54HC299/MM74HC299 features multiplexed inputs/ outputs to achieve full 8-bit data handling in a single 20-pin package. Due to the large output drive capability and TRI-STATE feature, this device is ideally suited for interfacing with bus lines in a bus oriented system.

Two function select inputs and two output control inputs of MM74HC299 are used to choose the mode of operation as listed in the function table. Synchronous parallel loading is accomplished by taking both function select lines S0 and S1 high. This places the TRI-STATE outputs in a high impedance state, which permits data applied to the input/output lines to be clocked into the register. Reading out of the register can be done while the outputs are enabled in any mode. A direct overriding CLEAR input of MM74HC299 is provided to clear the register whether the outputs are enabled or disabled.

The MM74HC299 is functionally as well as pinout compatible with the standard 54LS/74LS logic family. All inputs are protected from damage due to static discharge by internal diode clamps to VCC and ground.