| This is a book for engineers designing high-speed circuit boards. To the signal integrity engineer, this book will be a handbook of formulas and terminology as well as a refresher of basic electrostatic and electromagnetic principals. The high-speed circuit designer will find this book an easy entry into the electromagnetics and physics of high-speed signaling. It introduces concepts fundamental to high-speed signaling, such as lossy transmission line behavior, skin effect, and the characteristics of laminates and surface mount capacitors. The focus throughout is on the effects of dielectric and conductor loss on signal quality, with a particular emphasis on serial differential signaling. Coupling between transmission lines (especially in the context of crosstalk and odd/even modes) is discussed. Besides being useful in serial signaling, this has application to multiconductor busses.
This is a book about high-speed signaling on printed wiring boards (PWBs). The physical construction of PWBs determines the conductor’s resistance (discussed in Chapter 2), its self capacitance (covered in Chapter 3) and inductance (Chapter 4), and the coupling to neighboring conductors (Chapters 5 and 9). At the high frequencies of interest in this book, these electrical primitives appear on a PWB as distributed rather than lumped elements, giving rise to transmission line behavior.
It is thus necessary for the high-speed circuit designer to have an understanding of how PWBs are constructed and a sense of the trade-offs fabricators must make when manufacturing high-density, high-layer count PWBs. This chapter summarizes those characteristics impacting the electrical characteristics of PWBs and introduces some of the terminology used in the PWB design industry.
The larger PWB fabricators provide design for manufacturability (DFM) documents (see [1, 2] to cite just two examples) that detail the dimensional and many of the practical requirements necessary to create PWB artwork for their facility. These documents are helpful in understanding the practical state of the art in such things as via size, layer count, and trace width and spacing and can act as a primer to those unfamiliar with PWB technology. Additional underlying detail that is somewhat general in nature may be found in [3, 4]. |