The 74LV251 is a low-voltage Si-gate CMOS device and is pin and
function compatible with 74HC/HCT251.
The 74LV251 is an 8-input multiplexer with 8 binary inputs (I0 to I7), an
output enable input (OE) and three select inputs (S0, S1, S2). One of
the eight binary inputs is selected by the select inputs and is routed to
the outputs (Y, Y). Both outputs are in the high impedance OFF-state
(Z) when the output enable input is HIGH, allowing multiplexer
expansion by tying the outputs.