A Low power 10bit 500kS/s delta-modulated SAR ADC (DMSAR ADC) for implantable medical devices

An architecture of SAR ADC called the delta-modulated SAR ADC (DMSAR ADC) is proposed and designed for medical device applications. In the proposed DMSAR ADC, only the voltage difference between two successive samples is resolved to reduce the conversion steps and decrease the power consumption per channel up to 66%. The experimental chip is implemented in 0.18μm CMOS technology. At the digital supply voltage of 1.35V and Vref=1.00V, the measured power consumption per channel is 1.38μW (2.71μW) and the measured SNDR is 56.68dB (53.89 dB) for Fin=10Hz (7kHz). The ENOB is 9.12b and FoM is 39.54fJ/step.