33. CMOS XOR Gate

The CMOS inverters generate A' and B'. Two transmission gates then select the required signal based on input A.

• When A = 0, the first transmission gate passes B to Y.
• When A = 1, the second transmission gate passes B' to Y.

Therefore, Y becomes HIGH only when A and B are different.

Y = A' · B + A · B' = A ⊕ B