Computer Science & Engineering VLSI Lab →List Of Experiments

Schematic Design Of Transistor Level XOR & XNOR Gate.

XOR(exclusive OR)
For a 2 input XOR,the output of the gate is low when both the inputs are same(either both low or both high).The output is high if one and only one of the inputs is high.The function is addition modulo 2 and hence the gate is used in half adder

The schematic and truth table for 2 input A and B for XOR gate :-

SCHEMATIC OF XOR GATE


Input A Input B Output
0 0 0
0 1 1
1 0 1
1 1 0


XNOR(exclusive OR)
For a 2 input XNOR,the output of the gate is high when both the inputs are same(either both low or both high).The output is low if one and only one of the inputs is high.

The schematic and truth table for 2 input A and B for XOR gate :-

SCHEMATIC OF XNOR GATE



Input A Input B Output
0 0 1
0 1 0
1 0 0
1 1 1