#74LS251

Description: Multiplexer 8 to 1, 3-state Outputs

Datasheet: http://www.ti.com/lit/gpn/sn74LS251

Pinout:

      +-----------+
   I3 |[ 1]   [16]| VCC
   I2 |[ 2]   [15]| I4
   I1 |[ 3]   [14]| I5
   I0 |[ 4]   [13]| I6
    Y |[ 5]   [12]| I7
 ~{Y} |[ 6]   [11]| S0
~{OE} |[ 7]   [10]| S1
  GND |[ 8]    [9]| S2
      +-----------+