Sizing Up Three SiC MOSFETs That Recently Hit the MarketJune 20, 2020 by Jake Hertz
Multiple companies have announced new SiC MOSFETs—indicating growing popularity in the device and a promising future for solar and EV applications.
Power electronics has always been an important field in electrical engineering, but recently its importance has taken center stage with fields such as solar and electric vehicles gaining traction. At the heart of these flourishing industries is an important innovation in device technology: silicon carbide (SiC) MOSFETs.
SiC MOSFETs, especially 1200 V MOSFETs, have been designed with power efficiency in mind. According to Littelfuse and Power Semiconductors, they are praised for their low ON resistances, fast switching times, and high breakdown voltages. Fast switching times and low RDS(on) allows for decreased power dissipation when operating. High breakdown voltages allow for the MOSFET to operate under extreme power conditions without failing. Combine these three and you get a useful device for high power systems.
Within the past few weeks alone, multiple companies have released new generations of their SiC MOSFETs. For the sake of this article, we’ll look at the Mitsubishi N-Series SiC MOSFETs, ROHM Semiconductor 4th Generation SiC MOSFETs, and Alpha and Omega Semiconductor’s newest SiC MOSFET release.
Mitsubishi's N-Series MOSFETs
Mitsubishi Electric, an EV-facing company, broke the news of their new N-series MOSFETs about a month ago. In their words, this innovation will allow for “low power consumption and miniaturization of power supply systems, such as EV onboard chargers.”
Mitsubishi N-series MOSFET measures at 40 mm. Image used courtesy of Mitsubishi Electric
The N-series has an RDS(on) as low as 22 mΩ and a max current of 102 A. This device is said to improve power consumption in power supply systems by 85% compared to conventional Si-IGBTs. According to Mitsubishi Research, these specs give the N-series an industry-leading figure of merit of 1,450 mΩ·nC.
ROHM's 4th Gen SiC MOSFETs
With the introduction of their 4th Generation SiC MOSFETs, ROHM Semiconductor offers a 40% reduction in RDS(on) compared to their third generation.
ROHM’s 4th Gen SiC MOSFETs RDS(on) vs. VGS. Image used courtesy of ROHM Semiconductor
With a VGS of 15 V, these MOSFETs claim an RDS(on) as low as 14 mΩ. Inherently, lowering RDS(on) leads to larger parasitic capacitances—an important trade-off to note.
ROHM, however, claims to have reduced their gate-drain capacitance to achieve a 50% decrease in switching loss as compared to conventional products. Since this news is so fresh, many specs, such as IDmax and figure of merit, haven’t been released yet. Regardless, many of the impressive specs of the new generation show high promise in power applications.
Alpha and Omega's SiC MOSFET
Finally, Alpha and Omega Semiconductor’s newest SiC release also offers exciting improvements. Already in production, their AOK065V120X2 is offering specs such as an RDS(on) of 65 mΩ at a VGS of 15 V. These MOSFETs are specified to have a max current rating of 85 A.
Alpha and Omega Semiconductor’s SiC MOSFET RDS(on) vs. temperature. Image used courtesy of Alpha and Omega Semiconductor
While these specs are not as impressive as what is offered by both ROHM and Mitsubishi, the news is still significant. First, the news represents Alpha and Omega’s entry into the SiC market. Second, it’s the only device of the three that is currently in production. News of ROHM’s device is only a day old, and Mitsubishi states that sample shipments will begin this July.
Sizing Up the Three
While ROHM’s 4th Generation SiC MOSFETs seem to boast the most impressive specs (from what we know), any one of these new devices offers significant improvements over their predecessors. Each device offers huge benefits in high power applications where a conventional silicon MOSFET won’t cut it.
As a result, industries such as solar and EV could see notable benefits in the form of power savings and, consequently, smaller systems. Smaller and more power-efficient devices often represent cost savings and an eco-friendly footprint.
Learn More About SiC MOSFETs
What Does “99% Power Efficiency” Really Mean in Silicon Carbide MOSFETs?
Evaluating the Robustness of 1200 V SiC MOSFETs Under Short Circuit Conditions
Silicon Carbide Footprint Growing in Power Electronics
Do you often work with SiC MOSFETs? In your experience, what are the virtues of these devices over their silicon counterparts? Share your thoughts in the comments below.