SiC-Based Power Device Accepts Standard Gate Drive, Includes Kelvin Connection
Users of power devices know that choosing a suitable device is only part of the design story, and that driving the device—especially at higher current and voltage levels—is often a comparable challenge. The UF3C120150K4S, a TO-247-packaged, 1200-V silicon-carbide (SiC) FET device added to the UF3C FAST series from UnitedSiC, provides an architecture that eases the drive dilemma by maintaining gate-drive compatibility with non-SiC devices (see figure). It also adds a 4-leaded Kelvin-sense option for additional dynamic-performance benefits.
The 175°C (maximum junction temperature) device targets EV charging, photovoltaic inverters, switch-mode power supplies, power-factor-correction (PFC) modules, motor drives, and induction heating.
The UF3C120150K4S 1200-V power switch combines a high-voltage SiC JFET and a low-voltage silicon MOSFET for gate-drive compatibility, while the low-impedance Kelvin source-lead connection enhances dynamic performance.
The UF3C120150K4S enhancement-mode power switch combines a high-voltage SiC depletion-mode JFET and a low-voltage silicon MOSFET connected in series. In this configuration, the silicon MOSFET acts as the “control unit,” while the SiC JFET provides high-voltage blocking for the “off” state. Designers can replace their existing silicon-based power devices (IGBTs, FETs, SiC MOSFETs, or “superjunction” devices) and upgrade to this device while maintaining compatibility with existing gate drivers and gate-drive voltages.
The configuration also enables lower values of critical parameters such as on-resistance (RDS(on)) (here, 150 mΩ typical), output capacitance (Coss), gate charge (QG), and reverse-recovery charge (Qrr); doing so minimizes conduction and switching losses. Further, the cascode arrangement provides a high-performance reverse-conduction function, thus eliminating the need for an external anti-parallel diode.
The 4-lead Kelvin TO-247 package, which is ESD-protected (rated tri HBM class 2), offers faster switching and much “cleaner” gate waveforms than the standard 3-lead TO-247 package. It minimizes gate ringing and false triggering that otherwise might require limiting of switching speeds, both of which occur with the large common source inductance of 3-leaded packages. It can be easily screwed down or clamp-mounted for very low junction-to-case thermal resistance, appropriate for the high junction temperature of SiC devices such as this one. The UF3C120150K4S is priced at $6.14 each (1000-piece lots).
About the Author
Bill Schweber
Contributing Editor
Bill Schweber is an electronics engineer who has written three textbooks on electronic communications systems, as well as hundreds of technical articles, opinion columns, and product features. In past roles, he worked as a technical website manager for multiple topic-specific sites for EE Times, as well as both the Executive Editor and Analog Editor at EDN.
At Analog Devices Inc., Bill was in marketing communications (public relations). As a result, he has been on both sides of the technical PR function, presenting company products, stories, and messages to the media and also as the recipient of these.
Prior to the MarCom role at Analog, Bill was associate editor of their respected technical journal and worked in their product marketing and applications engineering groups. Before those roles, he was at Instron Corp., doing hands-on analog- and power-circuit design and systems integration for materials-testing machine controls.
Bill has an MSEE (Univ. of Mass) and BSEE (Columbia Univ.), is a Registered Professional Engineer, and holds an Advanced Class amateur radio license. He has also planned, written, and presented online courses on a variety of engineering topics, including MOSFET basics, ADC selection, and driving LEDs.