Time-Continuous Delta-Sigma A/D Converters: From Theory to Practical Implementation

The concept of delta-sigma A/D conversion is well known as a very efficient technique for the implementation of high resolution A/D converters in low to medium bandwidth applications. While mostly implemented by means of the switched-capacitor technique and thus as discrete time circuits in the past, continuous-time circuitry becomes the standard for the implementation of today´s ever-growing bandwidth applications. A brief summary of the key aspects of CT delta-sigma modulators is therefore given in this chapter, illustrated by recent CT implementations. Covered are the functionality of noise shaping converters, typical single-stage and multi-stage architectures for baseband applications and their implicit anti-aliasing feature and the influence and compensation of circuit non-idealities, e.g. jitter excess loop delay or coefficient mismatch in cascaded modulators