Lowest RDS(on) SiC FETs in DFN eight by eight format

3rd February 2020

UnitedSiC

Alex Lynn

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UnitedSiC has introduced the UF3SC065030D8 and UF3SC065040D8; a low RDS(on) SiC FETs available in the popular low-profile DFN eight by eight surface-mount package. The 650V devices replace two standard silicon devices, enabling engineers to build switching circuits with greater efficiency and higher power density than is possible with a discrete design approach.

Applications for the SiC FETs are expected to include LLC (inductor-inductor capacitor) and PSFB (phase-shifted full-bridge) power conversion at 50 to 500KHz in wireless and telecoms systems, as well as standard hard switched applications in PFC (Power factor correction).

The UF3SC065030D8S is a 650V SiC FET with an RDS(on) of 34mΩ, while the UF3SC065040D8S is a 650V SiC FET with an RDS(on) of 45mΩ. These are the lowest RDS(on) figures for switching devices in this voltage class available in the DFN eight by eight package. Both SiC FETs have a current rating of 18A (limited by wire count in the package), and a maximum operating temperature of 150C.

The parts employ the UnitedSIC unique stack cascode configuration to co-package a normally-on SiC JFET with a Si MOSFET, producing a normally-off SiC FET device. The SiC FETs can be driven at zero to ten volts or zero to 12V, and their gate-drive characteristics match those of standard Si FETs, IGBTs and SiC MOSFETs. The parts also feature a Kelvin gate return to enable cleaner drive characteristics.

The SiC FETs are pin-compatible, ‘drop-in’ improvements to other switching devices available in the DFN eight by eight package. Because their lower power dissipation enables switching at higher frequencies, designers can achieve greater conversion efficiency and greater power density in designs where space is at a premium. In addition, the low-profile DFN 8x8 surface-mount package supports a low-inductance design. Very low junction-to-case thermal resistance is achieved by using sintered silver die attach technology.

The UnitedSiC UF3SC065030D8S and UF3SC065040D8S have ultra-low gate charge and exceptional reverse recovery characteristics, making them well suited for switching inductive loads in any application that uses a standard gate drive. It also makes them applicable in high-frequency designs, since driver loss is minimal at switching frequencies of up to 500KHz. As the parts are robust with a low reverse recovery charge (Qrr), they handle hard switched operation with ease.