Editors' Notes—Volume 41, Number 2, 2007


The difficulty of maintaining true ground has been discussed in these pages numerous times, usually in terms of ac and dc behavior. However, circuits such as buck- and boost regulators, that rapidly and repeatedly switch large amounts of current, can cause large transient ground errors. The origin of this “ground-bounce” phenomenon is explained in easy-to-understand terms, leading logically to a sensible PC-card design approach that minimizes the transients—starting on page 3.

A low-dropout regulator (LDO) is a handy way to immunize a circuit against the battery discharge curve when the upstream voltage becomes so low that the output voltage of a conventional regulator would begin to drop. Some of the fine points of LDO design are discussed in the article starting on page 8.

At this writing, the Nintendo Wii’s successful entry to the games marketplace is legendary. A key internal contributor to its popularity is a 3-dimensional accelerometer that lets the player use natural motions similar to the motions used in a real game to play an electronic game. The role of dynamic iMEMS (integrated microelectromechanical systems) in making games more user-friendly is discussed starting on page 11.


Dr. Colin Lyden and Dr. Zoran Zvonar have been elevated to the distinguished position of ADI Fellow during our 2007 General Technical Conference, which attracted approximately 1,900 engineers from the Company’s design sites worldwide.

The Fellows honor is bestowed on a select group of engineers who have contributed significantly to ADI’s business and demonstrated important qualities, such as innovation, leadership, entrepreneurial ability, and consulting skills. In addition, an ADI Fellow must be a company ambassador, bridging across organizations and demonstrating an unparalleled ability to teach and mentor others within the company. With the latest inductions in this, the program’s 27th year, Analog Devices has a total of 33 Fellows within our community of 3,500 engineers worldwide.

“Engineering excellence and innovation continue to set ADI apart,” said Sam Fuller, vice president of Research and Development. “We are fortunate that exceptional engineers like Colin and Zoran, who are recognized both inside and outside the Company for their expertise, have chosen to make their careers at Analog Devices. Their work has challenged the conventional wisdom within the Company, extended our ambitions for new-product performance, and served as an inspiration for the next generation of engineers to sustain ADI’s record of innovation.”

Colin Lyden received his PhD in 1984 from University College, Cork, Ireland. He joined ADI in 1999 as an engineering director with leadership responsibility for the Limerick CAD group and the Cork Design Centre. His creative ideas and work, blurring the traditional distinctions between sigma-delta, successive-approximation, and pipelined converter architectures, have resulted in performance improvements in a range of ADI products, including the AD7982 and the AD7767 successive-approximation analog-to-digital converters.

Colin, who holds 15 U.S. patents, was the lead architect for a new CT medical-imaging analog front-end that achieved breakthroughs in both cost and performance—and has been designed into next-generation high-slice CT machines.

Zoran Zvonar, having earned his PhD at Boston’s Northeastern University in 1993, joined ADI in 1994 as one of the company’s first system engineers to specialize in communications algorithms. An expert in wireless system design for varied communications applications, Zoran has extensively published in leading technical journals. He also serves as an editor for the IEEE Communications Magazine and is co-author of several books focusing on GSM and third-generation wireless communications systems.

Zoran developed and validated a breakthrough system approach for wireless handsets that resulted in two patents and enabled direct conversion—the process of converting analog RF signals directly to digital baseband data—to be applied successfully to the GSM wireless communications standard. He was a member of the core technology design team for ADI’s SoftFone® and Othello® wireless product families.

Dan Sheingold[dan.sheingold@analog.com]


In November, I purchased an inexpensive aftermarket GPS navigation system for my car. The system can be helpful, even in well-known locations, where it alerts me to upcoming turns, can plot a scenic route on one of the parkways, and occasionally teaches me a new shortcut. It’s also entertaining on long road trips, where it continually counts down the remaining miles and minutes, its highly visible progress display making it seem that the destination is closer than it actually is. Its main purpose, of course, is plotting a course to an unfamiliar location. The combination of audio and visual clues makes finding addresses easy, and the routing options provide a simple way to choose the shortest route or the quickest route, to avoid toll roads or local roads, and to navigate around a detour.

The hidden beauty, however, is using the extensive collection of points-of-interest to show what’s available in an unknown area. Recently, a friend from Connecticut met me in Charlestown, Rhode Island, a town that is roughly halfway between our houses. Neither of us was familiar with the area. Upon arrival, we found that the restaurant that we had chosen for lunch was closed. No worries—the GPS showed us several other local restaurants, as well as the town beach, two National Wildlife Refuges, and a seventeenth-century gristmill. It helped us to enjoy a day trip in a beautiful, if unfamiliar town.

I have three complaints about this low-end GPS, however. The first, and most serious, is that the touchscreen is becoming less responsive as the summer temperatures in New England continue to rise. A few minutes in front of the air-conditioning outlet usually cures the problem, but I’m a fan of sunshine and open roofs. Too bad the manufacturer didn’t use an ADI capacitance-to-digital converter, which includes on-chip calibration logic to compensate for changes in temperature and humidity.

The second problem is that the GPS loses its signal when I travel through Boston’s Big Dig tunnels, making it unable to maintain its bearings or to provide instructions for lane splits and exits. Too bad it doesn’t include an ADI accelerometer, whose inertial navigation capabilities could provide positional information during these temporary signal losses.

The third minor irritation is that the aftermarket GPS has no connection to the car stereo, and thus cannot mute the music when it needs to provide spoken directions. Fortunately, my system gives several warnings before each turn, allowing me to turn the radio down when necessary.

Readers: What are the best features of your GPS, or your pet peeves with your systems? Designers: What should we be looking for in next-generation systems? Your comments are welcome.


Scott Wayne [scott.wayne@analog.com]

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