5.2 A 110dB SNR ADC with ±30V input common-mode range and 8μV Offset for current sensing applications

Abstract

This paper presents a high-resolution 110dB SNR ΔΣ ADC that achieves a ±30V input common-mode voltage range (CMVR) while powered from a single 5V supply. This beyond-the-rails capability is obtained by employing a capacitively coupled high-voltage (HV) chopper at the input of a switched-capacitor (SC) ΔΣ ADC. Furthermore, the use of correlated double sampling and system-level chopping results in a maximum offset of 8uV over the full CMVR. In contrast to a recent HV ADC [1], the ADC exhibits 30dB more resolution, while its CMVR extends below the negative rail.