Intelligent Power Amplifiers: Atlanta IC Developer VT Silicon Receives $3.3 Million to Develop WiMax Chips

Business Wire, Sept 12, 2007

ATLANTA -- Atlanta radio-frequency integrated circuit developer VT Silicon has received a $3.3 million round of financing from California-based Menlo Ventures. The funding will help the company design and produce prototypes of its new "intelligent power amplifier" chips for the next-generation of WiMax mobile devices.

Based on silicon-germanium (SiGe) semiconductor materials, the VT Silicon chips will include patent-pending distortion-prevention techniques - known as linearization enhancement - that are designed to support the complex signals used by WiMax devices. To reduce chip costs to justify high-volume consumer applications, the company is building its amplifiers on low-cost SiGe instead of the more exotic - and costly - gallium arsenide (GaAs) materials used in most existing WiMax power amplifiers.

"This funding will allow us to take the linearization techniques we have already proven in a test chip and apply them to commercial chips within the next 9 to 12 months," said Mike Hooper, VT Silicon's CEO. "Our plan is to be shipping samples to customers early next year and to begin ramping to production by the middle of next year."

VT Silicon is a member company of Georgia Tech's Advanced Technology Development Center (ATDC).

WiMax is intended to provide significantly higher bandwidth and broader coverage for the next generation of mobile devices that will support such applications as streaming video. Sprint Nextel Corp. has already announced plans to roll out WiMax service in large metropolitan areas during 2008, and as a result, manufacturers are rushing to provide the special chipsets the devices need.

That will require some engineering innovation, as the new WiMax mobile devices will demand more power - but be less forgiving of the distortion caused by nonlinear effects that occur at higher power levels, Hooper noted.

Meeting the technical demands in potentially high-volume devices will require new levels of optimization -- in addition to new techniques for controlling distortion. VT Silicon has already developed one linearization technique, and is working on others.

For its chips, VT Silicon has developed proprietary Linear Enhancement Technology (LET) that will permit the higher power levels. Because SiGe can support both conventional bipolar transistors as well as CMOS, the LET can be implemented on the same chip as the power amplifier, providing cost and design simplicity advantages.

"SiGe affords us the ability to put very sophisticated control and intelligence within the power amplifier because SiGe can combine both CMOS - which is low power control circuitry - and bipolar transistors in one fabrication process," Hooper noted. "It gives us the ability to get fairly complex, allowing us to make intelligent power amplifiers."

However, the designers will have to compensate for the relatively lower RF power levels currently produced by most SiGe power ICs. "We have some proprietary technologies to get the power we need," said Hooper. "We can be competitive with gallium arsenide on power levels."

The company initially plans to produce two power amplifiers for the WiMax market, operating at 2.5 GHz or 3.5 GHz. As a step toward volume manufacturing, it will work with customers to create a reference design for each prototype chip. Jazz Semiconductor Inc. of Newport Beach, Calif. will produce the chips.

Hal Calhoun, managing director at Menlo Ventures, is bullish on the future of the WiMax market - and VT Silicon's solutions. "We believe that the leading-edge technology from VT Silicon will be very competitive in this fast-moving market," he said. "The combination of silicon germanium and unique linearization techniques makes the company's technology attractive to the key players in this new market."

About VT Silicon: VT Silicon designs and manufactures multi-band radio frequency integrated circuit (RFIC) solutions for the mobile wireless broadband market. The company's products leverage novel linearization and efficiency enhancement technologies that enable original equipment manufacturers, original design manufacturers and reference design houses to manufacture broadband, highly-efficient, low-cost and small-footprint modules and transceivers. For more information, please visit (www.vtsilicon.com).

About Menlo Ventures: Menlo Ventures provides long-term capital and management support to early-stage and emerging-growth companies. It is one of Silicon Valley's oldest venture capital partnerships, and has organized and managed nine venture funds since its inception in 1976. The firm has more than $4 billion under management, and a team with more than 100 years of collective experience in technology, marketing, sales and general management. For more information, please visit (www.menloventures.com).

About the ATDC: Georgia Tech's Advanced Technology Development Center (ATDC) is a nationally recognized science and technology incubator that helps Georgia entrepreneurs launch and build successful companies. ATDC provides strategic business advice and connects its member companies to the people and resources they need to succeed. More than 100 companies have emerged from the ATDC, including publicly-traded firms such as MindSpring Enterprises - now part of EarthLink. For more information, please visit (www.atdc.org).