A 3rd-order Noise Shaped Multistage Open-Loop Current Controlled Oscillator-based ADC with Non-Linearity Compensation

A multi-stage, open-loop Current Controlled Oscillator (CCO)-based Analog-to-Digital Converter (ADC) is proposed for non-linearity compensation and enhanced noise shaping. This architecture consists of multiple CCO-based stages connected in a cascading manner. The digital outputs of these stages are skillfully combined through digital filters to both compensate for the distortion of the CCOs and increase the noise shaping order. We present an application example with three stages, demonstrating a significant reduction in distortion, particularly from the first stage, and a notable improvement in Signal-to-Noise and Distortion Ratio (SNDR) performance when compared to first-order structures.