The 74HC251 is a high-speed Si-gate CMOS device
and is pin compatible with low power Schottky TTL
(LSTTL). The 74HC251 is the logic implementation of
single-pole 8-position switches with the state of three
select inputs (S0, S1, S2) controlling the switch positions. Assertion (Y) and negation (Y) outputs are both provided. The output enable input (OE) is active LOW. Both outputs are in the high impedance OFF-state (Z) when the output enable input is HIGH, allowing multiplexer expansion by tying the outputs.
True and complement outputs
Both outputs are 3-state for further multiplexer expansion
Permits multiplexing from n-lines to one line
Output capability: standard
ICC category: MSI
16 pin DIP. Actual brand may vary from picture.