An audio cascaded ΣΔ modulator using gain-boost class-C inverter

This paper provides an audio 2-1 cascaded ΣΔ modulator using a novel gain-boost class-C inverter. By introducing a 3-µW gain-boost module, the inverter DC-gain is increased from 48dB to 67dB. The proposed inverter-based ΣΔ modulator chip is implemented in 0.13-µm CMOS process, and achieves 86-dB peak-SNDR, 89-dB peak-SNR and 90-dB DR over 22.05-KHz bandwidth at 1.2-V supply consuming 360µW, which demonstrates that the gain-boost class-C inverter is particularly suitable for micro-power high-resolution applications.