Exploration of the Synchronization Constraint in Quantum-dot Cellular Automata

Quantum-dot Cellular Automata (QCA) is a field-coupled nanotechnology which might enable design with high performance and extraordinary low energy dissipation. Infor-mation processing and flow in QCA is controlled by external clocks, which requires a proper synchronization already during circuit design phase. In this paper, we discuss the fundamental differences between local and global synchronicity in QCA circuits. Further, we show that it is possible to relax the global synchronicity constraint and discuss the consequent impact on the design performance. Simulation results indicate that the design size can be reduced by about 70% while the throughput performance declines by similar values.