Mobile Mom

The IEEE member has helped to advance the semiconductor industry for the past two decades

6 February 2009

When Susanne Paul was 13, she blew off a New Year’s bash to do something she says was way more fun: tinker with a computer.

“I was visiting some cousins over the holidays in the late ’70s and they had a first-generation Apple computer,” recalls Paul. “Everyone went out to celebrate New Year’s Eve, but I stayed and played with that computer all night. I was so fascinated that I saved up my babysitting money to buy an Atari PC two years later.”

So it’s probably no surprise that Paul, an IEEE member, has helped to advance the semiconductor industry for the past two decades. As cofounder and chief technologist of the semiconductor firm Black Sand Technologies, in Austin, Texas, she’s developing the world’s first commercial, silicon-based complementary metal oxide semiconductor (CMOS) cell phone power amplifier for 3G (third generation) mobile phones. Silicon chips are a cheaper technology that facilitates more complex functions, but until Paul figured out a way around it, could not survive the higher voltage levels required for 3G phone signal transmission. The firm is unveiling a prototype this month at the GSMA Mobile World Congress in Barcelona.

From 1999 to 2004, while at Silicon Laboratories, also in Austin, Paul developed the first such power amp for GSM (global system for mobile communications) units. It garnered her and the device numerous awards, including “2004 Innovator of the Year” and “Product of the Year,” both from Electronics Design Strategy News. Before that, while working for MIT Lincoln Laboratory in Lexington, Mass. and Digital Equipment Corp. (DEC) in Hudson, Mass., Paul helped develop electronic imagers, analog-to-digital converters, and microprocessors. She also holds more than 45 issued and pending patents in the semiconductor arenas involving electronic imagers, analog-to-digital converters and power amplifiers,

Paul attributes her success partly to a unique way of problem solving. “I tend to think differently,” she says. “Most engineers are analytically oriented, wanting to express everything in equations. It’s more natural for me to approach things conceptually. I think women in general tend to be more that way, but would you believe that in 20 years, I’ve never worked with another female engineer?

“Male engineers are sometimes uncomfortable when I formulate designs in my head—they prefer to see it in equations on paper,” she continues. “Early in my career I felt like I had to apologize for that but now I’m proud of it. It allows me to come up with ideas that are not so apparent to everyone else.”

Paul realized her heart lay in hardware while studying computer science and electrical engineering at MIT. After graduating with her bachelor’s in 1988, she headed to DEC to design circuits for its first-generation Alpha microprocessors. Paul joined the IEEE around 1990 for its conferences and networking opportunities. “The articles and information in IEEE Xplore digital library have been extremely helpful for furthering my own research, because I can learn from the trials and errors of the past,”she says. She spent the next nine years at MIT Lincoln Labs working on early electronic digital imaging technology, which is used in today’s digital cameras, but back then was limited to government and satellite applications. Along the way, Paul earned a master’s in 1995 and Ph.D. in 1999, both in electrical engineering from MIT.

By then, the Boston winters had taken their toll and she jumped at an offer from Austin-based Silicon Labs, a 50-person company that grew to 700 employees in six years. While there, Paul designed a CMOS GSM power amp—the circuitry used in signal transmitters— made from silicon instead of the traditional gallium arsenide, a feat that had stumped the industry for decades. Silicon is cheaper, more plentiful, and enables more complex processing and functionality than gallium arsenide, but couldn’t survive the necessary voltage levels.

“I rearchitected the circuits so they wouldn’t need high voltages to work,” Paul says. The breakthrough design won product and innovation awards. “When I went onstage to receive the awards, I was 39 weeks pregnant. Most of the audience were men but I got extra applause from the few women in the audience,” she laughs.

By 2006, Paul had two children and opted to be a stay-at-home mom. She bought a minivan, took the kids to playdates, and indulged her carpentry hobby by building a new room onto her house. By year’s end, two colleagues from Silicon Labs, Dave Pietruszynski and Jim Nohrden, asked for her help in launching a startup company to develop CMOS power amplifiers for 3G phones. “I was hesitant at first because I was pregnant with my third child,” she says. “But in the end it was too perfect an opportunity to pass up.”

Their new venture was Black Sand (a form of silicon) Technologies and the offer she couldn’t refuse was finding a way around the voltage breakdown problem once again. “The architecture for 3G phones is very different than that for GSM, so it required building a new design from scratch rather than applying what was done on GSM,” she says. “It’s brand new technical territory. Every step of the way, we need to invent new components and design methods not known in the industry, and we have to make do with computer-aided design tools that aren’t well suited for power amplifier design.”

The novelty prevents Paul from detailing how she tackled the problem, only saying that it still pales to running a household with three kids.

“Power amplifier design is one of the few new opportunities remaining in a fairly mature semiconductor industry,” she says. “There’s an existing high-dollar commercial market for it. Silicon opens up all kinds of possibilities for building in smart systems, better performance, and new functionality.”

For more information, check out Black Sand.

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