Microsemi Adds CLASS-E Reference Design Kit For 1000 W RF Generators

Irvine, CA -- Microsemi Corporation has introduced a new solid state 1KW, Single-Ended, CLASS-E reference design kit based on Microsemi's DRF1200 Driver/MOSFET hybrid.

The reference design kit enables the design engineer to immediately evaluate an 86% efficient 1000W CLASS-E RF generator. It provides an essential tool for developing high-power, high-voltage RF generators, optimizing efficiency and power densities for plasma generation, switch mode power amplifiers, pulse generators, ultrasound transducer drivers and acoustical optical modulators.

CLASS-E amplifiers offer a degree of efficiency unavailable with linear designs. The trade-off has been the high level of design complexity that engineers have either shied away from or spent months discovering the fundamentals of practical CLASS-E amplifier design. With the DRF1200/CLASS-E reference design kit an engineer can rapidly overcome the pitfalls of high voltage CLASS-E design. It demonstrates fundamental design techniques that can save months of countless design iterations.

Using the DRF1200 Hybrid as the core of the design, the reference amplifier enables performance previously unachievable with solid state CLASS-E amplifiers. The DRF1200 hybrid combines a driver, high voltage MOSFET and internal bypass capacitors making it a highly efficient, cost effective, high voltage solution.

The driver combined with optimally-located bypass capacitors is capable of driving high voltage MOSFETs at over 30MHz. The 1000V MOSFET enables higher voltage applications, greatly simplifying output matching and reducing the complexity of the output combining networks.

The kit includes the designer's application note, discussing the progression through various output voltages while identifying proper output waveforms necessary for the safe transition to the maximum 1KW, 925V peak output voltage. It also demonstrates efficiencies as high as 95% that can be achieved at lower voltages. The kit's circuit board comes fully assembled and mounted to a machined heatsink. It demonstrates the supply bypassing and high power inductor construction required for high power CLASS-E designs.

The DRF1200/CLASS-E is extremely versatile. After evaluating the 1KW generator design with the preloaded 1000V, 13A DRF1200 driver, an application can be easily modified for different power requirements using either 1000V, 26A DRF1201 or 500V, 50A DRF1202 hybrids.

The high power reference design features the DRF1200 hybrid in an air cavity-flangeless package for improved reliability over conventional plastic encapsulated packaging. Constructed with materials having closely matched CTEs maximizes system reliability by alleviating the stress between components during power cycling. Typical applications have demonstrated in excess of 1 million cycles with power densities of 700W/square inch. The flangeless package design also reduces cost by eliminating expensive copper-tungsten flanges typically found in high power RF packages.

Samples of the DRF1200, DRF1201, and DRF1202 are available now. All devices are available through the factory or authorized Microsemi distributors.

SOURCE: Microsemi Corporation