A Coplanar XOR Using NAND-NOR-Inverter and Five-Input Majority Voter in Quantum-Dot Cellular Automata Technology

Abstract

Quantum-dot cellular automata (QCA) offer a promising design paradigm for complementing conventional integrated circuits. The XOR plays a crucial role in arithmetic circuits and communications. Existing design schemes consume more operational components and thus are inefficient in terms of area and QCA cost at present. In this paper, a coplanar XOR composed of an NAND-NOR-Inverter (NNI) and a five-input majority voter (M5) is proposed for the first time. This new structure not only excludes complex crossovers but also has full accessibility to its input/output pins. The simulation waveforms and performance figures verify the functionality and merits of the proposed circuits. The implementation of the proposed XOR scheme in QCA consumes less overhead than that of its counterparts. Its occupied area and QCA cost are respectively reduced by 9.26% and 33.33% compared with the state-of-the-art XOR. To prove its practicability, multi-bit parity generators are also proposed in the means of hierarchically cascading the proposed XOR gates. The area and cost of the proposed 32-bit generator are respectively reduced by 39.47% and 33.33% compared with the existing best design.