A 16-µW 10-kHz BW incremental ΔΣ ADC with automatic EDO canceling for implantable neural recording

Abstract

This paper presents a DC-coupled, incremental ΔΣ analog-to-digital converter (ADC) based on two-step quantization for high-density implantable neural signal recording. To address the problem of electrode DC offset (EDO), a compensation circuit is proposed in this paper which can automatically cancel the EDO. Fabricated in a 180-nm CMOS process, the prototype ADC achieves a high input impedance, 20-mVpp linear input range, 60.3-dB signal-to-noise and distortion ratio (SNDR). Its core circuit has a power consumption of 16µW and an area of 0.0165mm². The refered-to-input (RTI) noise is 6µVrms (1-10kHz) and it can cancel the EDO up to ±90mV.