A frequency-scalable 15-bit incremental ADC for low power sensor applications

A 15-bit low-power incremental ADC is designed for sensor applications. The ADC is designed to be frequency-scalable by 1000 times from 1.67S/s to 1.67kS/s. To reduce power, an opamp with class AB characteristics is used. The design was fabricated in 0.18/μm CMOS and occupies an area of 0.35mm². Configured to operate at full-rate as a Delta-Sigma modulator, the ADC achieves 91.8dB peak SNDR while consuming 83μW from a 1.8-V supply. Operating as an incremental converter, the ADC powers off periodically to achieve frequency scalability, maintaining 84.7dB to 88.9dB peak SNDR while operating from 1.67S/S to 1.67kS/s and scaling analog power by up to 500 times.