A Universal ADC for Sensor Applications

This paper proposes and discusses a universal ADC for sensor applications that can covers almost all sensor applications with one ADC. The combination of SAR ADC and incremental ASADC can cover high speed with low resolution and low noise with low speed applications with a unified ADC. Two prototype ADCs have been developed for general purpose sensing systems and for CMOS image sensors. The former ADC realized open-loop integrators using dynamic amplifiers. High SNR of 84 dB has been achieved and high FoMs over the 170 dB can be kept in wide signal frequency from 62.5 to 625 kHz and the power dissipation is scalable with sampling rate. The SAR+ΔΣADC for CMOS image sensor can reduce the noise down to 66 μV and realized small occupied area of 20 μm × 770 μm.