Efficient designs of QCA Full-adder and 4-bit QCA RCA Circuits

Abstract Quantum-dot Cellular Automata (QCA) technology offers several advantages over traditional CMOS technology, including reduced power consumption, higher clock speeds, and increased density. QCA has the potential to overcome the physical limitations of CMOS, making it an attractive choice for the future of VLSI circuits. It uses quantum dots to represent binary information. Digital arithmetic operations are performed by adder circuits. A Ripple Carry Adder (RCA) is a digital circuit used in digital electronics to add multiple binary numbers together. In QCA technology, the implementation of such adders is notably different from traditional CMOS-based implementations due to the unique properties and principles of QCA. It is constructed by interconnecting a series of Full-adders. In this study, we introduce a high-performance single-bit Full-adder as well as 4-bit RCA circuit developed using QCA technology. Our proposed designs are simulated using QCADesigner 2.0.3 in a coplanar crossover way. Our 4-bit RCA design outperforms existing designs by achieving a remarkable 23% reduction in cell counts, 66% and 90% decrease in latency and circuit costs. Furthermore, power dissipation metrics for our single-bit Full-adder were ascertained using the QCAPro tool, with findings showing over 40% energy savings relative to the best current designs.