Noise Shaping SAR ADCs: Fundamentals, Challenges, Trends and Possibilities

The aim of this contribution is to provide an introduction and overview for newcomers to the study of Noise Shaping type Successive Approximation Register (SAR) converters, reviewing a general description of the fundamentals of Noise Shaping SAR (NS-SAR). This paper addresses the difficulties (i.e., open problems), analyzes the fundamental challenges and summarizes the latest developments; including the main problems, which are primarily in the loop filter and its passive/active implementations, mismatch in the DAC elements, among others. Some possible solutions for the dynamic correction of CDAC mismatch are also presented. Finally, some trends and future challenges are discussed.