LAUSR

A low-power fully-integrated analog front end for biopotential sensors is proposed. The signal conditioning circuitry features an integrating sampler and a digital-assisted electrode offset-cancellation loop. The chip is fabricated in a standard 0.18- $\mu \text{m}$ CMOS process. The supply voltage is 1.2 V and the quiescent current is $7.7~\mu \text{A}$ . Measurement results show that the analog front end achieves an in-band gain of 58 dB, a noise spectrum density of 46nV/ $\sqrt {\text{Hz}} $ and can tolerate ±60 mV electrode offset. The THD is below 1% with a 2mV_pp input. The analog signal is converted to digital code at 5kS/s by a 12-bit SAR ADC with 63.2 dB SNDR. The prototype IC is experimented with capturing ECG on human beings.