Compound Semiconductor June 2012

news digest ♦ Power Electronics

transistors and diodes to get even closer to the unipolar theoretical limit

SemiSouth Laboratories, a developer of SiC power semiconductor transistors and diodes, has secured its 30th US patent granted by the US Patent and Trademark Office.

SiC devices are rapidly gaining market share in the solar, UPS, traction, wind, automotive, and aerospace industries for their superior performance in high-efficiency, harsh-environment power applications

US Patent 8,169,022 was issued on May 1, 2012, and is entitled “Vertical Junction Field Effect Transistors and Diodes Having Graded Doped Regions and Methods of Making.” It was co- invented by Michael Mazzola, a co-founder of SemiSouth in 2000 when the company spun off of Mississippi State University.

“The underlying technology in this patent allows SemiSouth to fine tune their already performance- leading vertical channel junction field effect transistors and diodes to get ever closer to the unipolar theoretical limit. Customers can expect even better value from the products based on this patent,” says Mazzola.

“We are excited to receive our 30th US patent,” adds Jeffrey B. Casady, SemiSouth President & CTO and company co-founder. “Our technology is state-of-the-art in terms of performance per unit area. SemiSouth products deliver advanced, efficient, cost-effective power solutions that others cannot.”

In addition to 30 US patents, SemiSouth possesses 24 patents internationally and has 204 applications pending worldwide.

SemiSouth unveils 1700V / 1400mΩ SiC JFETs

The firm says that by using a depletion mode silicon carbide JFET, designers can achieve a fast start-up using no extra components such as an extra heat sink

SemiSouth Laboratories has unveiled a new 1700V/1400mΩ SiC JFET which it says simplifies

92 www.compoundsemiconductor.net June 2012

Traditional solutions either use an HV bleed resistor which results in a slow start-up at low line voltages and a high quiescent power loss, or are MOSFET- based which necessitate overload protection and can suffer from high power losses in the MOSFET under fault condition e.g. short circuit. Applications Engineer, Nigel Springett explains, “By using a depletion mode JFET, designers can achieve a fast start-up using no extra components. Our JFETs need no extra heat sink for this application.” The SJDT170R1400 will come in a newly developed SMD D2PAK-7L package in order to simplify PCB layout and optimise switching performance due to lower inductance.

This package will have a high creepage distance of 6.85mm in order to support 1700V applications and is 16 x 10 x 4.4mm. “We are confident that the SJDT170R1400 will become the de-facto standard for all auxiliary 3phase power supplies, as the benefits for the users are superior compared to traditional High Voltage MOSFET solutions and the cost become less for the total solution”, says Sr. Vice President Sales & Marketing, Dieter Liesabeths. SemiSouth is initially sampling the normally on 1700V/1400mΩ SJDP170R1400 in TO- 247-3L packaging; the SJDT170R1400 in surface mount D2PAK-7L high creepage package will sample in Q3 of 2012.

Avago and TriQuint bury the hatchet on BAW filters

The designer and developer of analogue III-V semiconductor devices and the gallium arsenide and gallium nitride innovator have come to an agreement to cross licensing patents

start up circuit design in 3-phase auxiliary power supplies.

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