A 160mV 670nW 8-bit SAR ADC in 0.13μm CMOS

An 8-bit SAR ADC capable of working under 160mV supply voltage is presented. To facilitate the ultra-low voltage comparator, a novel inverter-based amplifier is proposed and a dynamic latch with both gate and bulk driven input is exploited. An improved switching technique utilizing clock boosting and device stacking is employed for the ultra-low voltage sampling network. Implemented in a 0.13μm CMOS, the fabricated ADC works from 40kS/s to 400kS/s sampling rate under 160mV to 300mV supply voltage, respectively. Drawing 670nW from a single 160mV supply, the ADC achieves 0.5LSB DNL, 0.62LSB INL, 61.1dB SFDR and 7.3bit ENOB at a near-Nyquist input frequency of 19.7 kHz. To the best of authors´ knowledge, this is one of the lowest reported supply voltages in analog design.