Freescale Adds RF Power Transistor Options for WiMAX Base Stations

With its seventh-generation high-voltage (HV7) RF LDMOS technology, Freescale Semiconductor offers the RF power amplifier performance required for use in WiMAX base stations operating in the 3.5GHz band. Freescale's announcement marks the first time RF Laterally Diffused Metal Oxide Semiconductor (LDMOS) technology from any manufacturer has met these challenges.

"With the latest advancements in our HV7 RF LDMOS technology, Freescale is well positioned to serve the future of WiMAX and other high-frequency markets," said Gavin P. Woods, vice president and general manager of Freescale's RF Division. "Our high-voltage GaAs technology developments will continue to provide the highest level of efficiency of any competitive products in the marketplace, while extending our infrastructure presence to 6GHz."

Freescale, which already offers a portfolio of 12V GaAs Pseudomorphic High Electron Mobility Transistor (PHEMT) products, plans to continue development of high-voltage GaAs PHEMT technology that will result in higher-power GaAs devices for use in WiMAX system designs, as well as other applications between 2GHz and 6GHz.

By offering power transistors in RF LDMOS and GaAs PHEMT technology, Freescale's RF solutions support virtually any high-power wireless infrastructure application, with LDMOS performance up to 3.8GHz and GaAs PHEMT performance up to 6GHz.

WiMAX systems use a 64 quadrature amplitude modulation (QAM) orthogonal frequency-division multiplexing (OFDM) signal. QAM OFDM signaling presents some unique challenges to the power amplifier designer. RF power transistor linearity in back-off is critical, not only in its spectral form with mask requirements, but also in its quadrature form with the EVM (Error Vector Magnitude) requirement.

Prior to this announcement, silicon LDMOS technology did not provide an acceptable level of RF power performance at 3.5GHz. This meant that compound semiconductor devices, such as GaAs PHEMTs, were the only choice available for designers. Freescale's advanced 3.5GHz HV7 LDMOS devices now offer the efficiency, linearity and EVM performance required by WiMAX systems, providing designers with a choice between compound semiconductors and silicon LDMOS.

Samples of the initial 3.5GHz LDMOS device are available now. The MRF7S38075H is a 75Watt P1dB RF transistor capable of 42dBm (16W) average power while meeting WiMAX performance requirements over the 3.5GHz band. In addition, samples of 40W and 10W P1dB 3.5GHz devices are expected in February 2006. Samples of Freescale's first high-voltage GaAs PHEMTs are expected to be available in Q3, 2006.