RF LDMOS power transistor -> efficiency bar

Designed to set new standards for RF performance in ISM markets, Freescale
Semiconductor’s RF division has further pushed the power limits of LDMOS RF power transistors. Unveiled at the MTT-S International Microwave Symposium in Honolulu, Hawaii, the MRF6VP11KH delivers pulsed-RF output power of 1 kW at 130 MHz with higher drain efficiency and power gain. Pulse width is 100 s, duty cycle is 20% and powergain is rated 27 dB.
Operating at 50 V, the LDMOS provides designers of high-power systems such as magnetic resonance imaging (MRI) systems, CO2 lasers, plasma generators and other systems with significant benefits when compared to bipolar and MOSFET devices.
According to Freescale, the high gain at an unprecedented power level drastically reduces the number of parts required vs. traditional designs. This enables designers to significantly reduce board space requirements
and manufacturing complexity. Crafted for operation from 10 MHz to 150
MHz, the transistor leverages Freescale’s sixth-generation, very high-voltage (VHV6) LDMOS technology. “In delivering the MRF6VP11KH, we
have set industry benchmarks in efficiency, output power, reliability, and ease of design integration,” said Gavin P. Woods, vice president and general manager of Freescale’s RF division. “No other RF power device, whether LDMOS, MOSFET, or bipolar, can claim this achievement. We will continue to introduce ground-breaking devices for this marketplace, enabling our customers to break new barriers in system performance.”
The part delivers 65% drain efficiency, an exceptionally high value for any type of RF power device, said Freescale. When combined with gain of more than 27 dB, this level of efficiency makes it possible to dramatically reduce amplifier design complexity, gain stages, parts count, and circuit board real estate, said the maker.
An application requiring 2 kW pulsed output power and 45 dB of gain typically requires a 15 W pre-driver, two 15 W drivers, and eight final amplifiers when using MOSFETs or bipolar devices—a total of three stages and 11 devices. By comparison, stated Freescale, a design based on the new high voltage LDMOS transistor requires only three devices: a single 10 W LDMOS driver and two MRF6VP11KH final amplifiers, to produce the same output power and a highe
gain of 50 dB.
In addition, the 50 V bias voltage employed by the MRF6VP11KH produces higher terminal impedances for a given power level, which makes the device easier to match into an amplifier circuit. The thermal resistance of Freescale’s RoHS compliant, air-cavity ceramic package was measured at less than 0.13 oC/W θJC, providing efficient thermal management and reducing heat sink size.
Plus, it incorporates an integrated electrostatic discharge (ESD) protection eliminating the need for special handling procedures beyond those routinely observed in electronics manufacturing.
Samples of the MRF6VP11KH and a supporting reference design are available with production expected to begin in the fourth quarter.
For more information, visit www.freescale.
com.