This book proposes innovative circuit, architecture, and system solutions in deep-scaled CMOS and FinFET technologies, which address the challenges in maximizing the accuracy*speed/power of multi-GHz sample rate and bandwidth Analog-to-Digital Converters (ADC)s. A new holistic approach is introduced that first identifies the major error sources of a converter' building blocks, and quantitatively analyzes their impact on the overall performance, establishing the fundamental circuit-imposed accuracy - speed - power limits. The analysis extends to the architecture level, by introducing a mathematical framework to estimate and compare the accuracy - speed - power limits of several ADC architectures and variants. To gain system-level insight, time-interleaving is covered in detail, and a framework is also introduced to compare key metrics of interleaver architectures quantitatively. The impact of technology is also considered by adding process effects from several deep-scaled CMOS technologies.