Analysis and design of low-energy flip-flops

This paper develops a methodology for selecting and optimizing flip-flops for low-energy systems with constant throughput. Characterization metrics, relevant to low-energy systems are discussed, providing insight into timing and energy parameters at both the circuit and system levels. Transistor sizes are optimized for minimal delay under constrained energy consumption. This methodology is applied to characterization of various flip-flop styles and their comparison in 0.25 mum CMOS technology under scaled supply voltages. A transmission-gate master-slave latch-pair has the largest internal race margin, lowest energy consumption, and has energy-delay product comparable to much faster pulse-triggered latches.