Book excerpt: This book describes techniques for realizing wide bandwidth (125MHz) over-sampled analog-to-digital converters (ADCs) in nano meter-CMOS processes. The authors offer a clear and complete picture of system level challenges and practical design solutions in high-speed Delta-Sigma modulators. Readers will be enabled to implement ADCs as continuous-time delta-sigma (CT∆Σ) modulators, offering simple resistive inputs, which do not require the use of power-hungry input buffers, as well as offering inherent anti-aliasing, which simplifies system integration. The authors focus on the design of high speed and wide-bandwidth ΔΣMs that make a step in bandwidth range which was previously only possible with Nyquist converters. More specifically, this book describes the stability, power efficiency and linearity limits of ΔΣMs, aiming at a GHz sampling frequency.