A 2μW biomedical frontend with ΣΔ ADC for self-powered U-healthcare devices in 0.18μm CMOS technology

Abstract

This paper presents an ultra-low power analog front end (AFE) with ΣΔ modulator ADC meant for acquisition of biopotential signals. The system consists of a signal conditioning stage with programmable gain and bandwidth, a mixed signal automatic gain control (AGC), and a ΣΔ ADC. The full system is designed in UMC 18μm CMOS. The AFE achieves an overall linearity of more 10 bits with 0.47μW power consumption. The ADC provides 2nd order noise shaping while using single integrator and an ENOB of ~12 bits with 1.4μW power consumption. The system was successfully tested for a ECG signal from PTB database.