Wide-band Continuous-time Delta-Sigma Analog to Digital converter Design

This project focuses on the design, development, and testing of Delta-Sigma Modulators for wide-band applications. A key challenge in high-speed operation is the limitation of the oversampling ratio, necessitating the use of multi-bit quantizers to achieve a high signal-to-noise ratio (SNR). However, multi-bit digital-to-analog converters (DACs) introduce non-linearity, leading to distortion and degradation in and the signal-to-noise-and-distortion ratio (SNDR). For this reason, it is usually necessary to calibrate the multi-bit DAC with significant effort. By using dual quantization with a digital delta-sigma modulator (DDSM), high linearity can also be achieved without any calibration.

Another key challenge is the design of operational amplifiers (opamps) used in the RC integrators, which must achieve a sufficient gain-bandwidth product (GBW), often reaching the GHz range, while maintaining good linearity. This typically results in high power consumption. An alternative approach involves the use of GM-C integrators, which offer improved power efficiency but suffer from non-linearity.