London -- Is it possible to make a low-cost CMOS power amp for 3G cell phones that can operate with the power efficiency and robustness of a gallium-arsenide PA? Acco Semiconductor (Saint Germain en Laye, France) believes it has found a way.

But observers questioned whether the company's MASMOS technology can deliver as promised. And one analyst said the issue of CMOS PAs for 3G could be moot as more front-end modules appear that house the power amp along with filtering and a CMOS controller.

CMOS has been used for GSM cell phone power amps and for the PA requirements of Bluetooth and wireless LANs. But for the more-complex modulation schemes and higher frequencies of evolved 3G and WiMax, GaAs or similar technology has been necessary.

"The main difference between the GaAs-based technologies and the CMOS technology available today for power amplifiers is the breakdown voltage of the devices," said Denis Masliah, founder and chief technology officer of Acco. "In saturated amplifiers, for very high-efficiency regimes, the voltage across the device can reach 12 volts or more for a 3-V bias. And in linear amps, the back-off from the saturation makes it necessary to have an equivalent voltage excursion to limit distortion at the highest power levels.

"Furthermore, it is necessary to accept [impedance] mismatch from the antenna on the devices. [That] can produce a large voltage across the device, and can destroy it if its voltage capability is too low," said Masliah. Acco's MASMOS technology, he said, can "solve this breakdown issue for all CMOS technologies available for RF today, from 180 nm to 65 nm. MASMOS has a gain capability equivalent to GaAs-based devices and a breakdown of over 14 volts routinely."

Masliah said the company is "filing a cluster of patents" on its CMOS power amplifier concept but wouldn't say exactly what MASMOS is, or what Acco has done to improve the breakdown immunity of CMOS. He would only acknowledge that MASMOS is more than just a design or architectural tweak.

But if the new technology amounts to something physical in the process, does that make it nonstandard CMOS?

"This is something we don't want to discuss," Masliah said. "It is scalable with technology from 90 nm to 65 nm, 45 nm and so on. It is applicable to any CMOS foundry. It can be done on SOI wafers.

"Our goal is to have products in handsets in 2009," he added.

Acco hopes to tap a multibillion-dollar market, transforming itself into a fabless design house in the process. The company has been performing RF IC design services since 1994. "We've worked with 20 different companies--either system companies that wanted their own chip or semiconductor companies [that have outsourced] overflow work" to Acco, said Masliah.