Energy and Area Efficient Three-Input XOR/XNORs with Systematic Cell Design Methodology

In this brief, we propose three efficient three-input XOR/XNOR circuits as the most significant blocks of digital systems with a new systematic cell design methodology (SCDM) in hybrid-CMOS logic style. SCDM, which is an extension of CDM, plays the essential role in designing efficient circuits. At first, it is deliberately given priority to general design goals in a base structure of circuits. This structure is generated systematically by employing binary decision diagram. After that, concerning high flexibility in design targets, SCDM aims to specific ones in the remaining three steps, which are wise selections of basic cells and amend mechanisms, as well as transistor sizing. In the end, the resultant three-input XOR/XNORs enjoy full-swing and fairly balanced outputs. They perform well with supply voltage scaling, and their critical path contains only two transistors. They also outperform their counterparts exhibiting 27%-77% reduction in average energy-delay product in HSPICE simulation based on TSMC 0.13-μm technology. The symmetric schematic topologies significantly simplify and minimize the layout, as 26%-32% improvement in area is demonstrated.