Microsemi Introduces Flangeless RF Power MOSFET to Enable 165VDC Applications
Microsemi Corp. announced the addition of the ARF476FL transistor to its family of high voltage RF Power MOSFETs in lower-cost flangeless packages. The ARF476FL is targeted at high-power, high-voltage RF generators that are used extensively in plasma generation, CO2 laser exciters, medical MRI equipment, FM broadcast transmitters, and a wide variety of HF/VHF communications equipment including solid state broadband linear amplifiers from 1.5 to 60MHz and FM broadcast transmitters from 88-108 MHz.
To specifically address the needs of these demanding markets, Microsemi has developed proprietary 500V and higher wafer fabrication processes for making RF power MOSFETs. This is claimed to double a transistor’s safe operating area (SOA), to dramatically improve its resistance to load mismatch, to provide superior thermal stability, and significantly enhance Class AB operation reliability. The ARF476FL flangeless package is optimized for high power and high voltage by implementing an extended substrate that adds 3mm of creep distance and a lead frame that increases lead spacing. The dual MOSFET is internally configured for push-pull operation and is well suited for 165V applications.
Using a patented process and finer geometry, the ARF476FL is said to be able to deliver much higher peak power and RF gain than standard MOSFETs. It is capable of delivering 900W peak or 450W CW output at 150 MHz. The 165Vdc operating voltage simplifies output impedance matching circuitry and facilitates integrated assemblies combining a dc power supply and RF power amplifier, significantly reducing their size and overall system cost. The coplanar lead arrangement facilitates circuit layout and provides over 2500V isolation between any terminal and the mounting surface.
The ARF476FL flangeless package are claimed to lower thermal resistance and cost compared to ceramic packages with a copper tungsten flange. Microsemi’s flangeless package design uses an air cavity and closely matched CTEs that maximize system reliability by alleviating stress during power cycling. Typical applications have been demonstrated beyond one million cycles with a power density of 700W per square inch.
Samples and prototype production quantities of the ARF476FL are available now through the factory and authorized Microsemi RF distributors. At quantities of 100 pieces, the unit price is $82.47.
