#74LS688

Description: 8-bit magnitude comparator

Datasheet: http://www.ti.com/lit/gpn/sn74LS688

Pinout:

    +-----------+
  G |[ 1]   [20]| VCC
 P0 |[ 2]   [19]| P=R
 R0 |[ 3]   [18]| R7
 P1 |[ 4]   [17]| P7
 R1 |[ 5]   [16]| R6
 P2 |[ 6]   [15]| P6
 R2 |[ 7]   [14]| R5
 P3 |[ 8]   [13]| P5
 R3 |[ 9]   [12]| R4
GND |[10]   [11]| P4
    +-----------+