28 February 2011

SemiSouth ships first normally-off SiC JFET for up to 50kW

SemiSouth Laboratories Inc of Starkville, MS, USA( which designs and manufactures silicon carbide (SiC) technology for high-power, high-efficiency, harsh-environment power management and conversion applications) is now shipping its latest range of vertical trench JFETs (junction field-effect transistors) — including what is claimed to be the world’s first normally-off family of devices to handle up to 50kW — in commercial volume quantities.

The firm is rapidly expanding production capacity at its SiC wafer fabrication facility. As an independent, vertically integrated SiC manufacturer with epitaxial and vertical trench process technology, SemiSouth uses a proprietary and patented self-aligned JFET chip design enabling up to ten times smaller die size compared with silicon super-junction MOSFETs or the latest trench IGBTs, it reckons. The firm also holds the record for the lowest 1200V power transistor specific on-resistance (under 2.5mΩ/cm2).

The new SJEP120R100, SJEP120R063 and SJEP170R550 normally-off trench SiC power JFETs are compatible with standard gate drive circuitry and feature a positive temperature coefficient for ease of paralleling. The voltage-controlled devices also have a low Rds(on)max, low gate charge and low intrinsic capacitance. The SJEP120R100 (with an Rds(on) of 100mΩ) enables extremely fast switching with no ‘tail’ current up to its maximum operating temperature of 175ºC, and the SJEP120R063 (with an Rds(on) of 63mΩ) can enable switching losses of just 353µJ at 24A. These JFETs offer a blocking voltage of 1200V and exhibit temperature-independent switching behaviour. The latter device is being designed in by a number of solar inverter companies who are achieving product efficiencies of 98–99%.

SemiSouth also offers a normally-on 1200V SiC JFET (SJEP120R085) for users that can use the normally-on behaviour. It offers the same features as the normally-off SJEP120R100 JFET, plus a higher saturation current (50A), lower on-resistance per unit area (85mΩ total), and the same or better switching performance. The device is also being designed in at solar inverter and audio customers for high-efficiency or high-linearity applications.

At 1700V, the new 4A SJEP170R550 SiC JFET delivers a higher blocking voltage (1700V), five times lower on-resistance (550mΩ), about ten times lower output capacitance (COSS = 20pF) and gate charge (QG of 10nC) than competing 1500V silicon power transistors, it is claimed. The device has a maximum operating temperature of 175ºC, and is targeted at auxiliary flyback power supply applications running off the high voltage DC bus in AC drives, UPS (uninterruptible power supplies) and solar inverters.

“Our SiC JFETs enable the most energy-efficient power system designs now possible for a broad range of applications…and they are available in volume production," comments president Jeff Casady. "Power supplies and inverters can now be designed to run up to 50–75% more efficiently and operate at up to four to eight times higher in PWM [pulse width modulation] frequency,” he reckons. “The reasonably higher price of the JFET can be off-set by a substantial reduction in the size and cost of magnetics, heat sinks and enables a smaller and lighter overall solution.”

The SJEP120R100, SJDP120R085, SJEP120R063 and SJEP170R550 JFETs are available in plastic TO-247 packaging and are priced in 1000-piece quantities at $12.55 for the SJEP120R100, $15.50 for the SJDP120R085, $22.87 for the SJEP120R063, and $9.06 for the SJEP1270R550.

See related items:

SemiSouth orders largest commercial capacity SiC Planetary Reactor from Aixtron

Tags: SemiSouth SiC Normally-off SiC JFET

Visit: www.semisouth.com

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