The devices are normally-ON with zero voltage gate drive, making them particularly suited for applications such as very fast action, solid-state circuit breakers and circuit protection generally where a default to an ON-state is necessary in the absence of gate power. The devices are also commonly used in series connection with a Si-MOSFET as robust ‘supercascodes’, which give all the advantages of wide band-gap technology with very high operating voltages and easy gate drive. Other applications include electronic loads, wireless charging synchronous rectification and power switches in low power flyback converters where the JFET in a cascode configuration provides for easy startup.
Markets addressed are circuit protection in rail, electric aircraft and traction, along with high voltage switching power conversion.
As devices, SiC JFETs have an extremely good RDSA figure of merit (normalized ON-resistance with die area), giving low insertion loss in circuit protection applications. The parts can be easily paralleled, due to their positive temperature coefficient of RDSON and flat gate threshold voltage curve over temperature. When operated in ‘linear’ mode, SiC JFETs exhibit a wide Safe Operating Area (SOA) without current crowding and current filament formation that other technologies suffer from, making them particularly suitable for electronic loads and current limiters. Absence of a gate oxide in the SiC JFETs gives the added benefits of radiation hardness and general robustness.
UnitedSiC uses its proprietary 6-inch wafer process in the fabrication of the devices with advanced wafer-thinning and die-attach techniques for excellent junction-to-case thermal resistance.
The new Generation 3 devices are coded UJ3N120070K3S (1200V 70 mΩ), UJ3N120035K3S (1200 V 35 mΩ), UJ3N0650080K3S (650 V 80 mΩ) and UJ3N065025K3S (650V 25 mΩ). All of these options are available in a standard TO-247-3L package.
“UnitedSiC’s SiC JFETs offer unbeatable system value when you need normally-ON, super robust devices,” said Anup Bhalla, VP Engineering at UnitedSiC. “The need for circuit protection is growing in tandem with the continuing advancement of power electronics. Very fast