Q. The figure below shows the ππ‘β full-adder block of a binary adder circuit. Ci is the input carry and Ci+1 is the output carry of the circuit. Assume that each logic gate has a delay of 2 nanosecond, with no additional time delay due to the interconnecting wires. If the inputs Ai , Bi are available and stable throughout the carry propagation, the maximum time taken for an input Ci to produce a steady-state output Ci+1 isΒ _____nanosecond.
Sol:
Given that Ai and Bi are available throughout the carry propagation. The maximum time taken for an input C1 to produce a steady state output Ci+1 involves two gates as shown in figure. Each gate has a delay of 2ns Total time delay = 4 ns.