#74LS385

Description: Quad serial Adder

Datasheet: http://www.ti.com/lit/gpn/sn74LS385

Pinout:

     +-----------+
 CLK |[ 1]   [20]| VCC
  1S |[ 2]   [19]| 4S
1S/A |[ 3]   [18]| 4S/A
  1B |[ 4]   [17]| 4B
  1A |[ 5]   [16]| 4A
  2A |[ 6]   [15]| 3A
  2B |[ 7]   [14]| 3B
2S/A |[ 8]   [13]| 3S/A
  2S |[ 9]   [12]| 3S
 GND |[10]   [11]| CLR
     +-----------+