Accuracy Improved Low-Energy Multi-Bit Approximate Adders in QCA

The conjunction of approximate computing and emerging nanotechnology could lead to very powerful and energy efficient integrated infrastructures in the near future. Research in this field is already very active and promising. In this brief, we present the design of approximate binary adders that very effectively exploit the inherent logic and physical behaviors of the Quantum-dot Cellular Automata technology. With respect to state-of-the-art competitors, the 16-bit architecture, designed as proposed here, exhibits an energy-delay-product and an area occupancy up to ~9 and ~3.7 times lower, respectively, with an accuracy more than 10 times higher.