An asymmetric SRAM cell to lower gate leakage

Abstract

We introduce a new Static Random Access Memory (SRAM) cell that offers high stability and reduces gate leakage power in caches while maintaining low access latency. Our design exploits the strong bias towards zero at the bit level exhibited by the memory value stream of ordinary programs. Compared to conventional symmetric high-performance cell, our new cell reduces total leakage by more than 24% in the zero state at high temperature. With one cell design, total cache leakage is reduced by 24% at high temperature with no performance or stability loss. At low temperatures, where gate leakage is dominant, our cell reduces total cache leakage by 43%. We show that the new cell can be combined in an orthogonal fashion with asymmetric dual-V/sub t/ cells to lower both gate and subthreshold leakage, reducing total leakage by 45% to 60% with comparable performance and stability.