In the circuit shown, A and B are the inputs and F is the output. What is the functionality of the circuit?
- ALatch
- BXNOR
- CSRAM Cell
- DXOR
Solution & Step-by-step Explanation
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
This is an EXNOR logic.
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
| A | B | Y |
|---|---|---|
| 0 | 0 | 1 |
| 0 | 1 | 0 |
| 1 | 0 | 0 |
| 1 | 1 | 1 |