Robust Adders Based on Quantum-Dot Cellular Automata

This paper demonstrates designing adders on quantum-dot cellular automata (QCA) nanotechnology, which offers a way to implement logic and all interconnections with only one homogeneous layer of cells. This promising technology has a structural noise path problem, causing general circuit failure. We propose a robust full adder, which avoids the fore mentioned noise paths by careful clocking organization. We construct a serial adder and a ripple carry adder, which occupy a fraction of area compared to a previous noise rejecting design, have the smallest carry path delay, and are pipelined on ultra-fine-grained cellular level. The modular layouts are verified with the freely available QCADesigner simulator, using the coherence vector model.