XOR gates for low-energy and near-Vth operation

XOR gates are essential components of many logic circuits. With the aim of reducing energy dissipation, this paper proposes the use of genetic-algorithm-based optimization for XOR gates operating in the near-threshold region. We applied the proposed technique on four different types of XOR gates built using 22 nm devices. The resultant energy savings for the optimized gates ranged from 28% to 48% when compared with the traditionally-sized gates. The areas of the energy-optimized gates are also appreciably less than their conventional counterparts. The presented technique can be readily used for optimizing the gates for power, performance, noise-margin, etc.