In the circuit shown, A and B are the inputs and F is the output. What is the functionality of the circuit?

Q. In the circuit shown, A and B are the inputs and F is the output. What is the functionality of the circuit?

(A) Latch

(B) XNOR

(C) SRAM Cell

(D) XOR

Ans: XNOR

Solution:

Case A:

A = 0, B = 0

NMOS 1 → OFF

NMOS 2 → OFF

PMOS 3 → ON

PMOS 4 → ON

Output = 1

Case B and Case C

A = 0, B = 1 or

A = 1, B = 0

In both cases either of NMOS is ON and one of the PMOS is OFF.

Case D:

A = 1, B = 1

Both NMOS are ON

NMOS will pass logic high from input A and B

F = 1

Truth Table,