750V SiC FETs - Price, Performance or the Best of Both Worlds

According to UnitedSiC, that R_DS(on) value of 6mohms is less than half the nearest SiC MOSFET competitor. The new device also provides a robust short-circuit withstand time rating of 5μs.

The 9 new device/package options in the 750V SiC FET series include rated at 6, 9, 11, 23, 33, and 44mohms. All devices are available in the TO-247-4L package while the 18, 23, 33, 44, and 60mohm devices also come in the TO-247-3L. Complemented by the already available 18 and 60mohm devices, this 750V expanded series provides designers with more device options, enabling more design flexibility to achieve an optimum cost/efficiency trade-off while maintaining generous design margins and circuit robustness.

As with the company’s previous offerings, the Gen 4 SiC FETs are a ‘cascode’ of a SiC JFET and a co-packaged silicon MOSFET. This type of design is intended to provide the full advantages of wide band-gap technology - high speed and low losses with high temperature operation, while retaining an easy, stable, and robust gate drive with integral ESD protection. The advantages are quantified by Figures of Merit (FoMs) such as R_DS(on) x A, a measure of conduction losses per unit die area. Gen 4 SiC FETs achieve the lowest values in the market at both high and low die temperatures. FoM R_DS(on) x E_OSS/Q_OSS is important in hard-switching applications and is half the nearest competitor value. FoM R_DS(on) x C_OSS(tr) is critical in soft-switching applications and UnitedSiC device values are around 30% less than competitor parts, rated at 650V compared with UnitedSiC’s at 750V. For hard switching applications, the integral body diode of SiC FETs is superior in recovery speed and forward voltage drop to competing Si MOSFET or SiC MOSFET technologies. Other advantages incorporated into the Gen 4 technology are reduced thermal resistance from die to case by advanced wafer thinning techniques and silver-sinter die-attach. These features enable maximum power output for low die temperature rise in demanding applications.

With their latest improvements in switching efficiency and on-resistance, the new UnitedSiC SiC FETs are ideal for challenging, emerging applications. These include traction drives and on- and off-board chargers in electric vehicles 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 benefit from use of the devices for an easy boost in efficiency with their backwards compatibility with Si MOSFET and IGBT gate drives and established TO-247 packaging.

The new devices complement the four initial Gen 4 devices that were launched in December 2020. Those were available in 18 and 60 mohm options, with reduced on-resistance per unit area, and low intrinsic capacitance.

www.unitedsic.com