No abstract

In this paper the novel coplanar circuits for full adder implementation in Quantum-dot Cellular Automata (QCA) technology are presented. We propose a novel one-bit full adder circuit and then utilize this new circuit to implement novel four-bit Ripple Carry Adder (RCA) circuit in the QCA technology. The QCADesigner tool version 2.0.1 is utilized to implement the designed QCA full adder circuits. The implementation results show that the designed QCA full adder circuits have an improvement compared to other QCA full adder circuits.

Quantum-dot cellular automata (QCA) technology is a kind of nanotechnology utilized for building computational circuits. It can be a good technology for overcome CMOS drawbacks at nano-scale due to its low delay and area. The Content-Addressable Memory (CAM) is a very fast memory that can perform search operations in a very short time. This feature makes the relative popularity of these memories and many applications for them, especially in network routing and processors. In this study, a novel loop-based circuit is designed for the QCA memory unit, which reduces area, cell count, latency, and cost. The obtained results using QCADesigner tool version 2.0.3 demonstrate that the designed QCA memory unit utilizes 16 cells, 0.01 µm2 area, and 0.25 clock cycles and has a reduction of 33% in the number of cells, 50% in area, 50% in latency, and 75% in cost compared to existing works. Then, this memory unit is utilized to design an efficient structure for CAM circuit. The results show that the developed structure for CAM circuit has 0.75 clock cycles, 32 cells, and 0.03 µm2 area, and it has a reduction of 20% in the number of cells, 25% in area, 40% in latency, and 75% in cost compared to existing works.