A 128 Kbit SRAM With an Embedded Energy Monitoring Circuit and Sense-Amplifier Offset Compensation Using Body Biasing

Embedded SRAMs are continuing to be one of the most critical components that limit the performance and energy budget of today´s systems. To enable better system level optimization, this paper introduces an embedded energy monitoring circuit that measures the absolute energy consumption of a 128 kbit SRAM circuit that is fabricated using a 65 nm low-power CMOS process. Monitoring circuit results are measured to be accurate within 10% of the actual energy consumption and it works with minimal overhead (below 1% active power). Secondly, to achieve energy-efficient and high-performance SRAM operation, various circuit techniques are employed. 8T bit-cells with word-line voltage boosting is used to enable operation for a wide supply range from 370 mV to 1.2 V. Since variation effects are more prominent at low-voltages, SRAM performance is improved by using a two stage sensing scheme. Global sensing is performed by offset compensated sense amplifiers that leverage body biasing to achieve up to 2x offset reduction for only 3.5% area overhead compared to SRAM area.