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).
