High-Performance Silicon-Gate CMOS The MC74HC157A is identical in pinout to the LS157. The device inputs are compatible with standard CMOS outputs; with pullup resistors, they are compatible with LSTTL outputs. This device routes 2 nibbles (A or B) to a single port (Y) as determined by the Select input. The data is presented at the outputs in noninverted form. A high level on the Output Enable input sets all four Y outputs to a low level.