If the delays in the circuit below are as given in the table

If the delays in the circuit below are as given in the table, find the propagation delays from the inputs to A B, and A = B.

Solution

Case.1: A < B

Consider the path from input A3 to output A<B through x3. This paths consists 1 INV, 2 AND, 1 OR, 1 NOR gates.

The delay is sum of individual delays of all gates present on the path. i.e

30 + 2*50 + 60+60 = 250ps.

Case.2: A > B

Consider the path from input A3 to output A>B through x3. This paths consists 1 INV, 2 AND, 1 OR, 1 NOR gates.

The delay is sum of individual delays of all gates present on the path. i.e

30 + 2*50 + 60+60 = 250ps.

Case.3: A = B

Consider the path from input A3 to output A=B through x3. This paths consists 1 INV, 2 AND, 1 NOR gates.

The delay is sum of individual delays of all gates present on the path. i.e

30 + 2*50 + 60 = 190ps.