A 135mV 0.13μW process tolerant 6T subthreshold DTMOS SRAM in 90nm technology

Cell stability and tolerance to process variation are of primary importance in subthreshold SRAMs. We propose a DTMOS based 6T SRAM suitable for subthreshold operation. For variation tolerant memory peripheral circuitry, we apply beta-ratio modulation technique. DTMOS SRAM array fabricated in 90 nm technology operates down to 135 mV consuming 0.13 muW at 750 Hz. The proposed SRAM achieves 200% improvement in read static noise margin at iso-area compared to the conventional 6T SRAM at a supply voltage of 200 mV.