A novel low-voltage low-power SAR ADC for biomedical applications

Abstract

This paper presents a novel charge-redistribution successive-approximation register (SAR) analog-to-digital converter (ADC). The proposed ADC is based on a novel capacitive DAC switching scheme which employs unit capacitors for voltage sampling and charge redistribution. Compared with published capacitive DAC which uses the same unit size capacitor, the proposed DAC needs only 33% of the total switches. The proposed 8-bit SAR-ADC is designed in Global foundries 65nm CMOS process. SPICE simulation results show that the average switching energy can be reduced by more than 60% compared with published design. The simulated power consumption of the capacitive DAC is about 110 nW at 1.0 V power supply and 100KS/s. The simulated average power consumption of the ADC is about 2.8 μW.