High Speed CMOS Logic Quad 2-Input Multiplexers
Description
The Harris CD74HC157, CD74HCT157, CD74HC158 and
CD74HCT158 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