A Novel Toffoli Gate Design Using Quantum-dot Cellular Automata

In this paper, a novel reversible Toffoli gate that uses enhanced logic primitives is proposed. These primitives considered are three-input NAND-NOR-Inverter (NNI) gates and five-input majority-of-five gates. The Toffoli gate design is implemented without any inversion operation, which results in area and delay advantages. Furthermore, we adopt the proposed Toffoli gate as the building block to construct a 4-2 reversible priority encoder. Quantum-dot cellular automata technology was used to validate the proposed design. The experimental results show that the proposed design reduces the delay and the area by 46.15% and 28.71%, respectively, compared with the state-of-the-art design.