Implementation of High Performance Clock-gated Flip-flops

In this paper, optimum transistor sizing of clock-gated master slave flip-flops viz. Gated Master Slave Latch (GMSL) and clock-gated Transmission Gate Flip-flop (CG-TGFF) has been implemented for high performance based on Logical Effort (LE) theory. In contrast to the previous work where clock-gating was merely utilized only for reduction of total dynamic power dissipation, we have also optimized the delay caused due to addition of extra transistors for clock-gating circuit. A comparative study of power-delay product (PDP) and power-delay-area product (PDAP) for the aforementioned circuits is performed. Simulation results using 180nm/1.8V TSMC CMOS technology have indicated that GMSL offers upto 45.8% and 49.6% improvement in PDP and PDAP respectively when compared to CG-TGFF at 0% switching activity (all ones). Results have been verified for various switching activities of the data input with respect to clock signal frequency.

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