Non-Linearity Cancellation of Gm-C Based DSM

• Published in: IEEE International Symposium on Circuits and Systems proceedings pp. 1 - 5
• Main Authors: Zaky, Bishoy M., Kauffman, John G., Conzatti, Francesco, Ortmanns, Maurits
• Format: Conference Proceeding
• Language: English
• Published: IEEE 25.05.2025
• Subjects: Bandwidth; Circuits and systems; Delta-sigma; Gm-C integrator; Impedance; Limiting; Linearity; linearization; Simulation
• ISSN: 2158-1525
• DOI: 10.1109/ISCAS56072.2025.11044033

Continuous-time (CT) Delta-Sigma-Modulators (DSMs) are widely utilized in systems requiring wide bandwidth and high resolution. While opamp-based RC integrators are favoured for their excellent linearity, they introduce low-input impedance and complicate the ADC driver. On the other side, Gm-C integrators provide high input impedance, making them more power-efficient, but they suffer from non-linearity, thereby limiting the input range. This paper explores the limitations of a specific non-linearity cancellation technique applied in DSM system-level. The principles of this technique are reviewed, and the challenges of using it at low oversampling ratio (OSR) are investigated. A theoretical analysis is presented, matching with simulation results.