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At its 3rd annual Analyst Day in New York yesterday, RF Micro Devices Inc of Greensboro, NC, USA presented new technologies that enable what it claims are unprecedented levels of functional integration in RF applications.

The new technologies include hermetically sealed wafer-level packaging (WLP), micro-electro-mechanical-systems (MEMS), integrated conformal shielding, gallium nitride (GaN), gallium arsenide (GaAs) enhancement/depletion-mode (E/D) pseudomorphic high-electron-mobility transistors (pHEMTs) and GaAs bipolar field effect transistors (BiFETs). RFMD expects these to support its forecasted growth in 2008 and extend its reach into new cellular product categories, including cellular mode switches, filters, duplexers and other high-performance RF components for cellular handsets.

RFMD says that the foundation for the new technologies is its historical emphasis on Optimum Technology Matching (OTM), in which the firm’s designers select the optimum technology for each application according to cost and performance considerations. The latest developments drive OTM a step further, says RFMD, by leveraging a greatly expanded portfolio of enabling technologies optimized specifically for increased levels of functional integration in RF applications.

In addition to wireless opportunities, RFMD expects the new technologies to expand growth prospects in markets targeted by its newly formed Multi-Market Products Group (MPG), including wireless infrastructure, wireless access, standard products, broadband/consumer and aerospace & defense.

*Standard RF component portfolio expanded with RF switches

RFMD currently ships more than one million pHEMT switches per day with its highly integrated transmit modules for cellular handsets, according to Greg Thompson, VP of sales for MPG. Leveraging its expanding internal pHEMT manufacturing capabilities, which is being driven by the Cellular Products Group (CPG), RFMD is extending its standard RF components product portfolio by adding a wide range of RF switch products. The new portfolio will demonstrate some of the strategic benefits created by the combination of RFMD and Sirenza Microdevices, Thompson adds.

“The Multi-Market Products Group is bringing to market a broad range of high-performance, multi-purpose discrete RF switches that will build upon RFMD’s core manufacturing competences as well as our Cellular Products Group’s proven success in pHEMT switches,” says Norm Hilgendorf, general manager of the Standard RF Components business unit. “We plan to introduce more than 20 new switch products that will feature high-power, high-linearity, high-isolation and low-insertion-loss performance,” he adds.

Victor Steel, VP of research and development, says that RFMD’s current first-generation (depletion-mode) pHEMT technology with second-generation enhancement/depletion-mode (E/D) pHEMTs, since enhancement-mode pHEMTs can support power amplifier and low-noise amplifier functions, as well as lowering voltages. The new E/D pHEMTs will be implemented initially in wireless LAN front-ends, according to Steel, and longer-term in cellular handsets.

*RFMD to release three generation of BiFETs

Steel also says that RFMD is intending to release three generation s of BiFET technology, incorporating its best HBT process and ‘state-of-the-art’ pHEMT process technology. In particular, he says that there will be a version including RFMD’s AlGaAs HBTs and a version including its InGaP HBTs.

*Qualification of first-generation GaN process technology completed

RFMD also announced that it has completed the technical qualification of its first-generation 48V GaN process technology. Pre- production volume shipments to customers in multiple end markets have already begun.

RFMD says that the technology is suited to address growing customer requirements for higher power, higher efficiency and wider bandwidth. The firm is targeting multiple high-growth applications, including high-linearity CATV line amplifiers, military radar applications, wide-bandwidth wireless infrastructure power amplifiers, and power modules for new high-lumen light-generation applications.

“We have multiple products - both in production and in development - that will benefit from the insertion of our new GaN technology,” says Bob Van Buskirk, president of RFMD’s Multi-Market Products Group. The new process provides an immediate competitive advantage to the newly formed group, he adds. “The continued deployment of our GaN technology across multiple end-markets will support our expectations for revenue and margin expansion as our Multi-Market Products Group continues to grow.”

Van Buskirk adds that the new GaN process delivers higher efficiency, wider operating bandwidth and greater ruggedness than currently available technologies. “These performance characteristics are supporting favorable design activity across multiple high-growth applications,” he reckons.

RFMD claims that its high-efficiency, high-power GaN process exhibits best-in-class RF performance at 48V, with 5.6W/mm average Psat (saturated output power), over 60% average peak PAE (power added efficiency) and 24dB average small-signal gain measured at a frequency of 2.1GHz. The intrinsic electrical properties and outstanding reliability of the GaN process enables improvements over bandwidth, power and efficiency, versus currently available, conventional technologies, the firm adds. The median time to failure (MTTF) at 180 degrees Celsius (operating junction temperature) is calculated to be greater than 1 million hours using three-temperature testing over multiple wafer lots.

*RFMD launches MEMS technology for functional integration in RF

RFMD has also introduced its proprietary micro-electro-mechanical systems (MEMS) technology for RF and other applications.

The first devices will be an RF MEMS transmit/receive switch and a mode-switch for 3G multimode handsets. The MEMS switch technology will help to accelerate 3G deployment by reducing the product footprint and improving efficiency, and hence extending handset talk time. When combined with RFMD’s GaAs, silicon-on-insulator (SOI) and silicon process technologies for front-end solutions, the RF MEMS switch technology will set new standards for low-cost, small size, and very high performance front ends, the firm claims.

The MEMS switches will also be used in the output circuit of power amplifiers (PAs) to create a tunable PA, which RFMD expects to enable a truly adaptive transmitter solution.

“RFMD is the only company capable of combining mixed-signal CMOS, power management, power amplifiers, RF switches and RF MEMS in cost-effective, wafer-level packaged, single-chip solutions,” claims Victor Steel, VP of research and development.

“Existing RF MEMS switch technology is based on small fabrication lots and wafer-to-wafer packaging techniques, which result in high device cost,” adds Gabriel M. Rebeiz, University of California at San Diego professor and early pioneer in MEMS development. “The RFMD approach, with its high level of integration on silicon, addresses this problem head-on and will result in improved yield, higher performance and much lower cost.”

The devices are high-power, ohmic contact MEMS switches that are post-processed above-IC on RF CMOS SOI wafers and are encapsulated in hermetically sealed wafer-level packaged (WLP) dielectric domes. All circuitry necessary for operation is integrated into the underlying CMOS, including the generation of the large voltages and control signals required for reliable actuation of power MEMS switches. The devices fully support RFMD’s rigorous cellular RF power module requirements, including low insertion loss and high isolation (typ. 0.2dB/35dB @ 1.9GHz) and high harmonic rejection (typical >90dBc), while also meeting stringent requirements for reliability and cost of design and production, the firm claims.

RFMD is also commercializing other MEMS devices, such as RF MEMS filters, RF MEMS resonators (crystal replacement) and MEMS sensors. The firm expects its MEMS technology, coupled with its existing core competencies in high-performance RF systems, to ultimately enable single-chip front ends and software-defined radios capable of accommodating any wireless protocol (cellular or non-cellular).

To support its continued MEMS development, RFMD is also constructing a 200mm MEMS R&D wafer fab, located with RFMD’s GaN R&D organization in a new facility in Mooresville, NC.

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