CMOS Sigma-Delta Converters: Practical Design Guide

Chapter 4

Circuit-Level Design, Implementation, and Verification

The behavioral modeling and simulation techniques described in Chapter 3 can be used for the high-level synthesis and verification of Ms so that the modulator-level specifications are efficiently mapped onto building-block (circuit-level) specifications. Thus, at this stage of the design cycle, the modulator is still modeled at system level, but the electrical performance parameters of all M circuit elements (switches, capacitors, amplifiers, transconductors, comparators, etc.) have been already derived from the high-level sizing process. Those parameters are in turn the circuit-level specifications, which constitute the start point for the electrical (transistor-level) and physical design process of the modulator. This process—conceptually illustrated in Figure 4.1—comprises a number of successive steps in which the initial behavioral-model diagram of the modulator is transformed into a circuit schematic—initially implemented with macromodels and finally with transistors—afterward into a layout, and finally into a chip implementation for experimental verification in a laboratory.

Figure 4.1 Conceptual step-by-step design flow of Ms.

This chapter gives some design issues and practical recipes to complete the design ...