The 74HC173; 74HCT173 is a quad positive-edge triggered D-type flip-flop. The device features clock (CP), master reset (MR), two input enable (E1,E2) and two output enable (OE1,OE2) inputs. When the input enables are LOW, the outputs Qn will assume the state of their corresponding Dn inputs that meet the set-up and hold time requirements on the LOW-to-HIGH clock (CP) transition. A HIGH on either input enable will cause the device to go into a hold mode, outputs hold their previous state independently of clock and data inputs. A HIGH on MR forces the outputs LOW independently of clock and data inputs. A HIGH on either output enable pin causes the outputs to assume a high-impedance OFF-state. Operation of the output enable inputs 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.