SiC FET enables new levels of design flexibility

UnitedSiC has reacted to power designer requests for higher-performance, higher-efficient SiC FETs with what is claimed to be the industry’s best 750V, 6mohm device. At an RDS(on) value of less than half the nearest SiC MOSFET competitor, the new device also offers a robust short-circuit withstand time rating of 5ms. It includes nine new device/package options in the 750V SiC FET series, rated at 6, 9, 11, 23, 33, and 44mohms. All devices are offered in the TO-247-4L package, while the 18, 23, 33, 44, and 60mohm devices also arrive in the TO-247-3L. Complemented by the currently available 18 and 60mohm devices, this 750V expanded series offers designers more device options, facilitating more design flexibility to obtain an optimum cost/efficiency trade-off while keeping generous design margins and circuit robustness.

Gen 4 SiC FETs from the company are a ‘cascode’ of a SiC JFET and a co-packaged silicon MOSFET. These together offer the full advantages of wide band-gap technology – high speed and low losses with high-temperature operation, while preserving an easy, stable, and robust gate drive with integral ESD protection. The advantages are quantified by FoMs such as RDS(on) x A, a measure of conduction losses per unit die area. Gen 4 SiC FETs deliver the lowest values in the market at both high and low die temperatures. FoM RDS(on) x EOSS/QOSS is essential in hard-switching applications and is half the nearest competitor value. FoM RDS(on) x COSS(tr) is critical in soft-switching applications, and the company's device values are around 30% less than competitor parts, rated at 650V compared with its 750V. For hard switching applications, the integral body diode of SiC FETs is better in recovery speed and forward voltage drop to competing Si MOSFET or SiC MOSFET technologies. Other advantages included in the Gen 4 technology are decreased thermal resistance from die to case by advanced wafer thinning techniques and silver-sinter die-attach. These features allow maximum power output for low die temperature rise in demanding applications.

With these latest improvements in switching efficiency and on-resistance, the new SiC FETs are excellent for challenging, emerging applications. These incorporate traction drives and onboard chargers in EVs and all stages of uni- and bi-directional power conversion in renewable energy inverters, power factor correction, telecoms converters and AC/DC or DC-DC power conversion generally. Established applications also profit from using the devices for an easy boost in efficiency with their backwards compatibility with Si MOSFET and IGBT gate drives and TO-247 packaging.

As Chris Dries, president and CEO of UnitedSiC, states: “The UnitedSiC Gen 4 SiC FETs are unquestionably the performance leaders within competing technologies and set a new benchmark in wide bandgap switch technology. The new range additions now provide further options for all performance and budget specifications, and a wider range of applications.”