Advanced Power Technology RF has added the ARF475FL to its high-voltage, flangeless packaged, RF power MOSFETs. It uses a newly patented process and finer geometry that delivers much higher peak power and RF gain than previous high-voltage parts. It operates reliably at dc voltages up to 165 V. The ARF475FL uses two die, configured for push-pull operation and is capable of delivering 1000 W pulsed output and 300 W CW at up to 150 MHz. High-power, high-voltage RF generators are used extensively for plasma generation, CO2 laser exciters, medical MRI equipment and a variety of HF/VHF communications equipment, such as broadband linear amplifiers. To address the needs of these markets, APT has developed a proprietary ultrahigh-voltage wafer fabrication process for making RF power MOSFETs. This doubles the transistor's available safe operating area (SOA), dramatically improves its resistance to load mismatch, provides superior thermal stability, and significantly enhances the ability to reliably operate in Class AB. The 165 Vdc maximum operating voltage simplifies output impedance-matching circuitry and facilitates integrated assemblies combining dc power supply and RF power amplifier to significantly reduce the size and overall system cost, according to the supplier.

The ARF475FL comes in the flangeless T3 package, which lowers thermal resistance and cost compared to ceramic packages with a copper tungsten flange. To obtain the high power dissipation, the backside of the package is lapped to provide an optimum thermal interface surface to mate with the system heat sink. Power cycle results in typical applications have been demonstrated beyond one million cycles with a power density of 700 W/square inch. The coplanar lead arrangement facilitates circuit layout and provides more than 2500 V isolation between any terminal and the mounting surface.

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