The PI74FCT157T/257T and PI74FCT2157T/2257T are highspeed quad 2-input multiplexers. The common select input can be used to select four bits of data from two sources. The four buffered outputs present the selected data in the true (non-inverting) form. The PI74FCT157T/2157T has a common, active-LOW, Enable input (E). When E is inactive, all four outputs are held LOW. The PI74FCT157T/2157T can generate any four of the 16 different funtions of two variables with one common variable. The PI74FCT157T/2157T can be used as a function generator or to move data from two different groups of registers to a common bus. The PI74FCT257/2257T has a common Output Enable (OE) input. When OE is HIGH, all outputs are switched to a high-impedance state allowing the outputs to interface directly with bus-oriented systems.