A 40nm CMOS full asynchronous nano-watt SAR ADC with 98% leakage power reduction by boosted self power gating

This paper presents an ultra low power and ultra low voltage SAR ADC. Full asynchronous operation and boosted self power gating are proposed to improve conversion accuracy and reduce static leakage power. Test chip fabricated in 40nm CMOS process has successfully reduced leakage power by 98% and it performs ENOB of 8.2bit and consumes only 0.65nW with 0.1kS/s at 0.5V. The power consumption is scalable up to 4MS/s and power supply range from 0.4 to 0.7V. The best figure of merit (FoM) of 5.2fJ/conversion-step was obtained with 20kS/s at 0.5V.