Digital Signal Integrity: Modeling and Simulation with Interconnects and Packages [Paperback]

For advanced courses in digital design.
This state-of-the-art book provides students with techniques for predicting and achieving target performance levels. Gives students all the theory, practice, general signal integrity issues, and leading-edge experimental techniques they need to accurately model and simulate those interconnections and predict real-world performance.

Preface

Effects of interconnects on the electrical performance of digital components, such as microprocessors, have historically been small enough to handle with simple rules of thumb. As clock rates, bus widths, and bus speeds have increased, packaging and interconnects have more importance and in some cases actually limit or define the system, where silicon performance is usually found to be the gating factor. This role reversal will become more common, and it may be that packaging and interconnects dominate electrical considerations at some point in the future as networks become more prominent.

The relatively recent growth of packaging and interconnects as significant issues in electrical performance means that relatively few resources exist for learning and training. Much of it exists as scattered applications notes, many of which are quite useful but are sometimes somewhat dated (i.e., notes on ECL rather than CMOS) or are from the less accessible technical literature. Since many organizations are newly finding the need for expertise in the field, in-house experts may not be available to act as mentors.

This book represents my efforts at collecting and deriving the necessary material to support a career in digital signal integrity modeling and simulation. A huge part of such a job is package and interconnect modeling from electromagnetic simulation and/or measurements. By necessity, the book spans a broad spectrum of techniques, including electromagnetic simulation, transmission line theory, frequency-domain modeling, time-domain modeling, analog circuit simulation, digital signaling, and some architectural issues, to put it all in perspective. Such a broad technological reach makes for a very interesting and challenging job. Since I believe that the number of engineers working this area will need to increase dramatically to support the technological trends, I hope that this book will provide a sufficient set of tools to help engineers succeed in this field.

The goal of the book is to provide detailed introductory material that is self-consistent and self-contained. As such, there are very few references. There is nothing in the book that is new to the field, so technical credit must go to the innumerable contributors to the technical literature, application notes, and standards.

The book is organized to move gradually from broad, general topics to specific modeling techniques. Particular emphasis is placed on rigorous derivation and on multiconductor interconnects. Chapter discusses the role of signal integrity in digital systems. Chapters and then cover issues in signaling and signal integrity. Chapters through cover detailed concepts in basic passive circuit components, with particular emphasis on multiconductor interconnects. One of the more difficult aspects of detailed simulations in signal integrity is the need to model multiconductor interconnects such as sockets, packages, edge connectors, and buses. Experimental characterization of interconnects is covered in chapter, where emphasis is on measurements of very small parasitics for high leadcount interconnects. Interconnect modeling is covered in chapters and, where distinction is drawn between low-frequency lumped modeling and high-frequency wideband modeling. Because interconnects are often physically small, lumped modeling is often the optimal choice. Finally, chapter provides extended coverage of signal integrity topics and represents advanced application of material and concepts from prior chapters.

The manuscript was typeset using running under Linux on a PC clone based on a Tyan motherboard with a Cyrix processor. The text was prepared using a custom text editor written in Tcl/Tk. Circuit simulations used Berkeley SPICE 3f4. The figures were prepared using Xfig. Symbolic manipulation usedMathematica.

Brian Young
Austin, Texas

• State-of-the-art techniques for predicting and achieving target performance levels
• Theory, practice, general signal integrity issues, and leading-edge experimental techniques

Model and simulate high-speed digital systems for maximum performance

Maximizing the performance of digital systems means optimizing their high-speed interconnections. Digital Signal Integrity gives engineers all the theory and practical methods they need to accurately model and simulate those interconnections and predict real-world performance. Whether you're modeling microprocessors, memories, DSPs, or ASICs, these techniques will get you to market faster with greater reliability. Coverage includes:

• In-depth reviews of inductance, capacitance, resistance, single and multiconductor transmission lines, generalized termination schemes, crosstalk, differential signaling, and other modeling/simulation issues
• Multiconductor interconnects: packages, sockets, connectors and buses
• Modal decomposition: understanding the outputs generated by commercial modeling software
• Layer peeling with time-domain reflectometry: its power and limitations
• Experimental techniques for characterizing interconnect parasitics

In Digital Signal Integrity, Motorola senior engineer Brian Young presents broad coverage of modeling from data obtained through electromagnetic simulation, transmission line theory, frequency and time-domain modeling, analog circuit simulation, digital signaling, and architecture. Young offers a strong mathematical foundation for every technique, as well as over 100 end-of-chapter problems. If you're stretching the performance envelope, you must be able to rely on your models and simulations. With this book, you can.

BRIAN YOUNG is a Member of the Technical Staff at the Somerset Design Center, Semiconductor Product Sector, Motorola, working on packaging, interconnects, and I/O design for PowerPC microprocessors and the RapidIO Interconnect Architecture. For over seven years he has specialized in simulation, modeling, measurement, and performance studies for high-speed signaling with microprocessors, fast static RAMs, and DSPs. He has served as an Assistant Professor in the Department of Electrical Engineering at Texas A&M University, College Station, and as an adjunct professor in the Department of Electrical Engineering at the University of Texas, Austin. Dr. Young holds a Ph.D from the University of Texas, Austin and holds six patents related to packaging. He has published numerous articles in conferences and journals.

Preface

Effects of interconnects on the electrical performance of digital components, such as microprocessors, have historically been small enough to handle with simple rules of thumb. As clock rates, bus widths, and bus speeds have increased, packaging and interconnects have more importance and in some cases actually limit or define the system, where silicon performance is usually found to be the gating factor. This role reversal will become more common, and it may be that packaging and interconnects dominate electrical considerations at some point in the future as networks become more prominent.

The relatively recent growth of packaging and interconnects as significant issues in electrical performance means that relatively few resources exist for learning and training. Much of it exists as scattered applications notes, many of which are quite useful but are sometimes somewhat dated (i.e., notes on ECL rather than CMOS) or are from the less accessible technical literature. Since many organizations are newly finding the need for expertise in the field, in-house experts may not be available to act as mentors.

This book represents my efforts at collecting and deriving the necessary material to support a career in digital signal integrity modeling and simulation. A huge part of such a job is package and interconnect modeling from electromagnetic simulation and/or measurements. By necessity, the book spans a broad spectrum of techniques, including electromagnetic simulation, transmission line theory, frequency-domain modeling, time-domain modeling, analog circuit simulation, digital signaling, and some architectural issues, to put it all in perspective. Such a broad technological reach makes for a very interesting and challenging job. Since I believe that the number of engineers working this area will need to increase dramatically to support the technological trends, I hope that this book will provide a sufficient set of tools to help engineers succeed in this field.

The goal of the book is to provide detailed introductory material that is self-consistent and self-contained. As such, there are very few references. There is nothing in the book that is new to the field, so technical credit must go to the innumerable contributors to the technical literature, application notes, and standards.

The book is organized to move gradually from broad, general topics to specific modeling techniques. Particular emphasis is placed on rigorous derivation and on multiconductor interconnects. Chapter discusses the role of signal integrity in digital systems. Chapters and then cover issues in signaling and signal integrity. Chapters through cover detailed concepts in basic passive circuit components, with particular emphasis on multiconductor interconnects. One of the more difficult aspects of detailed simulations in signal integrity is the need to model multiconductor interconnects such as sockets, packages, edge connectors, and buses. Experimental characterization of interconnects is covered in chapter, where emphasis is on measurements of very small parasitics for high leadcount interconnects. Interconnect modeling is covered in chapters and, where distinction is drawn between low-frequency lumped modeling and high-frequency wideband modeling. Because interconnects are often physically small, lumped modeling is often the optimal choice. Finally, chapter provides extended coverage of signal integrity topics and represents advanced application of material and concepts from prior chapters.

The manuscript was typeset using running under Linux on a PC clone based on a Tyan motherboard with a Cyrix processor. The text was prepared using a custom text editor written in Tcl/Tk. Circuit simulations used Berkeley SPICE 3f4. The figures were prepared using Xfig. Symbolic manipulation usedMathematica.

Brian Young
Austin, Texas