34. CMOS XNOR Gate

The CMOS inverters generate A' and B'. Two transmission gates select either B' or B 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 equal.

Y = A' · B' + A · B = (A ⊕ B)'