The ’HC157, ’HCT157, ’HC158, and ’HCT158 are quad 2-input multiplexers which select four bits of data from two sources under the control of a common Select input (S). The Enable input (E\) is active Low. When (E\) is High, all of the outputs in the 158, the inverting type, (1Y\-4Y\) are forced High and in the 157, the non-inverting type, all of the outputs (1Y\-4Y\) are forced Low, regardless of all other input conditions.

Moving data from two groups of registers to four common output busses is a common use of these devices. The state of the Select input determines the particular register from which the data comes. They can also be used as function generators.

The ’HC157, ’HCT157, ’HC158, and ’HCT158 are quad 2-input multiplexers which select four bits of data from two sources under the control of a common Select input (S). The Enable input (E\) is active Low. When (E\) is High, all of the outputs in the 158, the inverting type, (1Y\-4Y\) are forced High and in the 157, the non-inverting type, all of the outputs (1Y\-4Y\) are forced Low, regardless of all other input conditions.Read more