The 74HC574; 74HCT574 is an 8-bit positive-edge triggered D-type flip-flop with 3-state outputs.
The device features a clock (CP) and output enable (OE) inputs. The flip-flops will store the state
of their individual D-inputs that meet the set-up and hold time requirements on the LOW-to-HIGH
clock (CP) transition. A HIGH on OE causes the outputs to assume a high-impedance OFF-state.
Operation of the OE input does not affect the state of the flip-flops. Inputs include clamp diodes.
This enables the use of current limiting resistors to interface inputs to voltages in excess of VCC.