MC54/74F399

The MC54/74F398 is a high-speed quad 2-port register. It will select four bits of data from either of two sources (Ports) under control of a common Select input (S). The selected data is transferred to a 4-bit output register synchronous with the LOW-to-HIGH transition of the Clock input (CP). The 4-bit Dtype output register is fully edge-triggered. The Data inputs (I0x, I1x) and Select input (S)of MC54/74F398 must be stable only a setup time prior to and hold time after the LOW-to-HIGH transition of the Clock input for predictable operation.