MM54HC173/MM74HC173 TRI-STATEÉ Quad D Flip-Flop General Description The MM54HC173/MM74HC173 is a high speed TRI-STATE QUAD D TYPE FLIP-FLOP that utilizes advanced silicongate CMOS technology. It possesses the low power consumption and high noise immunity of standard CMOS integrated circuits, and can operate at speeds comparable to the equivalent low power Schottky device. The outputs are buffered, allowing this circuit to drive 15 LS-TTL loads. The large output drive capability and TRI-STATE feature make this part ideally suited for interfacing with bus lines in a bus oriented system. The four D TYPE FLIP-FLOPS operate synchronously from a common clock. The TRI-STATE outputs allow the device to be used in bus organized systems. The outputs are placed in the TRI-STATE mode when either of the two output disable pins are in the logic ``1'' level. The input disable allows the flip-flops to remain in their present states without having to disrupt the clock. If either of the 2 input disables are taken to a logic ``1'' level, the Q outputs are fed back to the inputs, forcing the flip flops to remain in the same state. Clearing is enabled by taking the CLEAR input to a logic ``1'' level. The data outputs change state on the positive going edge of the clock. The 54HC/74HC logic family 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.