Signal Integrity for PCB Designers by Vikas Shukla




You can buy this book using paypal for $40 here

Here is the list of topics covered in the book.

Introduction
Timing Relationship between Signal
Transmission Line
Parasitic effects of Resistor, Capacitor and Inductor
Power Supply ( PDN) Design
Power Plane Stack up design
Simulation Using Hspice
Crosstalk
Designing for EMI
Tips for Singal Integrity
Impedance matching and calculation
Characterization of High Speed Bus


The book covers numerous examples and question answer at the end of each chapter. Buy this boook here

Preface

The purpose of writing Signal Integrity for PCB Designers is to elevate Printed Circuit Board (PCB) designers to a level where they can understand challenges presented in the design of high speed digital PCBs. PCB designers, more often than not, depend upon the signal integrity experts to guide them in the form of design rules for the PCB layout. This book is expected to form a bridge between the signal integrity experts and the PCB designers.

During my experience in the design of high speed PCBs I came across PCB designers who had to read a document given by the signal Integrity expert and implement the constraints in the PCB design. This approach creates a kind of signal integrity divide where, there are two groups of persons working on a design Ė those who know signal integrity and those who donít. One obvious drawback of this scheme is that, those who donít know the reasons behind the signal integrity rules may not know what could make the design better than those presented by the signal integrity expert. More importantly, they do not know what happens to the integrity of the signal if certain rules are relaxed for the reason of cost or for the reason of reducing the routing complexity. After reading the book they should be able to pose reasonable questions to the signal integrity experts whenever they feel that certain compromise can lead to simplified routing, better performance or reduced cost.

PCB designers must develop an intuitive approach while observing the design rules. I have tried to write the book in such a way as to help them develop a feel for the subject and generate awareness.

This book attempts to answer some of the common questions raised in a high speed PCB design. What is characteristic impedance? What is the role of the bypass capacitor? How critical is the placement of the bypass and bulk capacitor? What is differential bus and what is the basic design rule for routing differential traces? What is the role of power and ground planes in a PCB design? What is length matching and how much tolerance is allowed in a typical PCB design traces?

This book will not make you a signal Integrity expert. It will however, prepare you to become one. If you are willing, you may like to cover other books and use some of the simulation tools to graduate to become signal integrity expert. With the background of this book you should be able to apply your own thought process in new problems of signal integrity and high speed PCB designs. You should be able to create a simulation environment and play with, what if scenarios and derive your own conclusions.

I have tried to avoid use of advanced mathematics as much as possible. Final results have been presented and real life examples have been given to make better understanding of the facts. The PCB designer should be able to design a reasonably good high speed PCB for existing technologies if he follows this book. The design rules for most common interconnect technologies, for example, DDR, DDR II, PCI-X, PCI Express, HyperTransport, USB 2.0 and numerous others have been standardized. After following this book, I expect the PCB designers to be able to follow the design rules for their particular application.

The PCB designers will have to be curious to learn one thing at a time to understand the reason behind the design rules presented to them. They must not hesitate to try to arrive at their own rules which can result in better or simpler implementation, reduced cost They should be able to ask the question - why not this rule ? This book should help them in their adventures.

Many independent PCB designers show incapability in designing a PCB for high speed. They need to depend entirely upon an experienced Signal Integrity expert for successful completion of a high speed PCB board. This may lead to cost escalation for smaller projects with very limited budgets, but which still come under the preview of high speed design. An alternative approach under this scenario will be to have the PCB designer get some in depth knowledge of the high speed design. The integrated approach saves money and reduces productsí design cost. The PCB designer should get enough expertise to know which area needs an expert advice. Simpler areas, e.g. power ground plane and routing, capacitor placements, trace impedance calculation, termination resistor placements should be analyzed and done by the PCB designer. PCB designer can even run simple simulation to preview signal quality under a given PCB trace geometry and a driver and a receiver model. He can run simulation to estimate cross talk. This will leave only few areas where expert advice can be sought. The expert advice and in-depth analysis will be required when designing a new circuit or topology or a complex multiple circuit interconnected topology. I do not believe in a separation between the PCB designer and the Signal Integrity engineer. However, the PCB designer should be ready to devote a lot of time to understand the nuances of the signal integrity, which they may be unwilling to do, as most of them are often pressed to meet a deadline to finish the design. But it will be rewarding if they do spend a little amount of time understanding one thing at a time.

Most PCB designers already do a number of signal integrity tasks in the form of following design rules. Because of their practical exposure, it should be easy for them to extend their understanding of the signal integrity knowledge.

Future requirements of design engineer will show greater demand for persons with integral knowledge and an integral experience. In PCB and electronic circuit design area, we may witness greater demand for person experienced in architecture design, schematic capture, PCB design and signal integrity. The more domains you know, the less is time wasted in communication between two persons or group of persons in communicating the design needs and checking the implementation. It reduces the design cost and ultimately reduces the product cost, especially for lower volume products. While knowing everything may seem a lot, it is actually a matter of taking keen interest in the fields surrounding your job.

I will conclude that my efforts are rewarding if I am successful in elevating the PCB designers even a little bit.

Vikas Shukla
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