ABSTRACT
An important problem that arises during the design of a single-chip mixed-signal radio is the crosstalk from digital to analog. Successful integration of analog and digital circuits on one chip can lead to advantages in economics and form factor. However, putting both types of circuits together on a chip introduces an important route for crosstalk from digital to analog, namely, the common substrate. This crosstalk, which we call substrate noise coupling, can seriously harm the analog circuits. The chapter demonstrates how a linearized physical model allows applying isolation techniques as part of a systematic and controlled approach to solve substrate noise coupling problems. It discusses the generation of substrate noise and the corresponding macromodeling. The chapter also discusses substrate noise propagation and modeling of the impact of substrate noise on analog circuits. It provides a discussion on guard rings that are a means to suppress the impact or generation of substrate noise.
