CD74HC257M (TEXAS INSTRUMENTS)

The CD74HC257M is a 2-input high speed CMOS Quad Multiplexer with non-inverting 3-state outputs. It selects four bits of data from two sources under the control of a common Select Input (S). The output enable input OE is active low. When OE is high, all of the outputs (1Y-4Y) are in the high impedance state regardless of all other input conditions. Moving data from two groups of registers to four common output buses is a common use of the 257. The state of the Select input determines the particular register from which the data comes. It can also be used as a function generator.