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Signal Integrity by Example

by: Fadi Deek, Mentor, A Siemens Business

Signal integrity issues remain a concern for many in the electronics industry. This micro eBook details the importance of eliminating signal integrity challenges. Written by signal integrity engineer Fadi Deek of Mentor, A Siemens Business, the chapters explore four possible signal integrity problems using an understanding of essential signal integrity principles.

Deek explores how to reach effective design solutions and make strong engineering tradeoffs through analysis techniques, best design principles, and software tools to achieve accurate simulations and measurements. This eBook has something to offer for any engineer interested in identifying problems, root causes, and solutions surrounding electronic transmissions.

Fadi Deek
In 2005, Fadi received his B.S. degree in computer and communications from the American University of Science and Technology (AUST) in Beirut, Lebanon. That same year, he joined Fidus Systems as a design engineer. He designed circuit boards at Fidus for three years. In 2010, he received his M.S. in electrical engineering from the University of Arkansas in Fayetteville. He then joined Mentor, A Siemens Business, as a corporate marketing engineer. In 2013, Deek became a corporate application engineer supporting the HyperLynx tool suite. In parallel, he is also pursuing his Ph.D. at the University of Colorado in Boulder under the supervision of Dr. Eric Bogatin.

Mentor, A Siemens Business, is a world leader in electronic hardware and software design solutions providing products, consulting services, and award-winning support for the world’s most successful electronic, semiconductor, and systems companies. We enable companies to develop better electronic products faster and more cost-effectively. Our innovative products and solutions help engineers conquer design challenges in the increasingly complex worlds of board and chip design. Corporate headquarters are located at 8005 S.W. Boeckman Road, Wilsonville, Oregon 97070-7777. Website:

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Not a signal integrity expert? No problem! With HyperLynx you can run fast and accurate simulations from the design planning phase, throughout the design process, and in the post-layout stage, to ensure that your products can be manufactured and work as intended in the field.

This book has been technically reviewed by the following experts in the PCB industry:
Eric Bogatin
Happy Holden

Chapter Summaries

  • Chapter 1

    Chapter 1: Impedance

    Chapter 1 outlines the basic concepts of characteristic, instantaneous, and driver output impedance. The chapter also covers driver features and package effects.
  • Chapter 2

    Chapter 2: Reflections and Terminations

    Chapter 2 addresses how to engineer proper terminations to minimize reflection noise. This includes a discussion of reflection and noise margins, termination strategies, and single-bit responses.
  • Chapter 3

    Chapter 3: Crosstalk

    Chapter 3 explores near-end and far-end crosstalk, and the effects of multiple aggressors on victim nets. This chapter also discusses root causes of crosstalk and solutions for resolving crosstalk issues.
  • Chapter 4

    Chapter 4: Differential Pairs

    Chapter 4 introduces differential pairs, differential and common signals, and methods to terminate them. Additionally, the chapter compares channel-to-channel crosstalk in tightly versus loosely coupled differential pairs.

What Our Readers Are Saying

Interconnects are no longer transparent, and if you don’t engineer signal integrity problems out of your design at the beginning, your product may not work. This is the warning Fadi Deek, corporate application engineer with Mentor Graphics, starts with in his new eBook titled Signal Integrity by Example.

-Eric Bogatin
Full Review

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Book Recommendation -- By Eric Bogatin

Interconnects are no longer transparent, and if you don’t engineer signal integrity problems out of your design at the beginning, your product may not work. This is the warning Fadi Deek, corporate application engineer with Mentor Graphics, starts with in his new eBook titled Signal Integrity by Example.

In each of the four sections, he starts with a few of the essential principles, then poses examples that demonstrate these principles. I like the approach. Unlike other books that take a general approach to signal integrity, this book takes a few deep dives to apply the simple principles to explain relatively complex effects.

Deek offers a simple method to reverse engineer the output impedance of any driver—measure its open circuit voltage and find the load resistance when the output voltage drops by half.

Even the simplest circuits with real driver models can yield complicated-looking ringing waveforms. This eBook looks under the hood and identifies two often neglected sources of reflections: the package model and the input gate capacitance of the receiver. By considering these two features, many of the mysterious ringing effects can be instantly understood.

This eBook is the first in a series from Mentor Graphics. It covers four topics: transmission lines and impedance, reflections and terminations, crosstalk in microstrip and striplines, and differential pairs and signals. The next eBook in this series will cover PDN design.

While the essential principles provide a strong foundation to apply your engineering judgment, this book leverages many simulations as virtual prototypes in which to explore the details of design space. However, Deek cautions that whenever you do a simulation, you should always practice safe simulation by first anticipating what you expect to see. If you don’t see what you expect, investigate the reason.

For example, engineering judgment and many application notes suggest that tightly coupled differential pairs should have less channel-to-channel crosstalk than loosely coupled differential pairs.

In a simple simulation of the crosstalk between two differential pairs, Deek demonstrates that, in some cases, this expectation does not match the real world. He shows that when differential impedance and line width are kept fixed and the coupling in a pair changes, two loosely coupled pairs have less crosstalk than two tightly coupled pairs with the same channel spacing.

By looking at the fringe fields, Deek is able to show the root cause of this behavior and recalibrate how we think about and solve signal integrity problems.

If you care about signal integrity, you are sure to pick up a few nuggets of insight from this new eBook.

Happy HoldenHappy Holden is the retired director of electronics and innovations for GENTEX Corporation. Formerly, he was the chief technical officer for the world’s largest PCB fabricator—Hon Hai Precision Industries (Foxconn). Prior to Foxconn, Holden was the senior PCB technologist for Mentor Graphics and advanced technology manager at Nan Ya/Westwood Associates and Merix. He previously worked at Hewlett-Packard for over 28 years as director of PCB R&D and manufacturing engineering manager. He has been involved in advanced PCB technologies for over 47 years.

Eric BogatinEric Bogatin is currently the dean of the Teledyne LeCroy Signal Integrity Academy. Additionally, he is an adjunct professor at the University of Colorado – Boulder in the ECEE department, where he teaches a graduate class in signal integrity and is also the editor of the new journal Signal Integrity Journal. Bogatin received his BS in physics from MIT, and MS and PhD in physics from the University of Arizona in Tucson. He has held senior engineering and management positions at Bell Labs, Raychem, Sun Microsystems, Ansoft and Interconnect Devices. Bogatin has written six technical books in the field, and presented classes and lectures on signal integrity worldwide.