Chapter 3 - The Right ADC for the Right Application

Abstract

The chapter contains four real-world applications: temperature, pressures, light sensing, and motor-control. In these applications, one decides whether a successive approximation register (SAR) or Ʃ-Δ converter is appropriate. The chapter discusses the most common analog-to-digital converter (ADC) problems and provides solutions for these problems. The SAR converter can service some of these applications, while the sigma-delta ADC can better service others. Some applications can utilize both converters, with a minimum number of trade-offs. At the system level, an appropriate ADC can produce the proper number of noise-free bits, or one can use an analog front-end gain cell plus a lower resolution ADC at a lower cost. This is a design architecture trade-off where cost, board space, and number of components come into play.