Design and Evaluation of a Carry-Skip Adder in Quantum Cellular Automata Technology

Adders are among the most practical and useful circuits in microprocessors. They could also be used in other arithmetic operators. Traditionally, they are fabricated using CMOS technology. However, CMOS has faced some challenges in the nanoscale regime such as reduced gate controllability and high leakage currents. In contrast, Quantum Cellular Automata (QCA) is a promising alternative for the challenges of the next generation digital circuits. Based on QCA idea, in this paper a Carry-Skip Adder (CSA) is designed, which as far as investigated, has not been previously presented in related works. As CSA adders are generally faster than ripple ones, our simulation results also confirm that the proposed CSA outperforms the state-of-the-art ripple and carry lookahead adders and produces the result three QCA clock cycles faster even in the worst-case scenario. In addition, the proposed QCA adder outperforms its CMOS counterpart in terms of speed and power consumption.