With the increasing power requirements of Artificial Intelligence (AI) processors, server power supplies (PSUs) must deliver more and more power without exceeding the defined dimensions of the server racks. This is driven by a surge in energy demand for high-level GPUs, which could consume 2 kW or more per chip by the end of the decade. These needs, as well as the emergence of increasingly demanding applications and the associated specific customer requirements, have prompted Infineon Technologies AG to extend the development of SiC MOSFETs to voltages below 650 V. The company is now launching the new CoolSiC MOSFET 400 V family, which is based on the  second-generation (G2) CoolSiC technology introduced earlier this year. The new MOSFET portfolio was specially developed for use in the AC/DC stage of AI servers,  complementing Infineon’s recently announced PSU roadmap . The devices are also ideal for solar and energy storage systems (ESS), inverter motor control, industrial and auxiliary power supplies (SMPS) as well as solid-state circuit breakers for residential buildings.

The new family features ultra-low conduction and switching losses when compared to existing 650 V SiC and Si MOSFETs. Implemented in a multi-level PFC, the AC/DC stage of the AI Server PSU can attain a power density of more than 100 W/in³ and is proven to reach 99.5 percent efficiency. This is an efficiency improvement of 0.3 percentage points over solutions using 650 V SiC MOSFETs. In addition, the system solution for AI Server PSUs is completed by implementing CoolGaN transistors in the DC/DC stage. With this combination of high-performance MOSFETs and transistors, the power supply can deliver more than 8 kW with an increase in power density by a factor of more than 3 compared to current solutions.

The new MOSFET portfolio comprises a total of 10 products: five R _DS(on) classes from 11 to 45 mΩ in Kelvin-source TOLL and D²PAK-7 packages with .XT package interconnect technology. The drain-source breakdown voltage of 400 V at T _vj = 25°C. makes them ideal for use in 2- and 3-level converters and for synchronous rectification. The components offer high robustness under harsh switching conditions and are 100 percent avalanche tested. The highly robust CoolSiC technology in combination with the .XT interconnect technology enables the devices to cope with power peaks and transients caused by sudden changes in the power requirements of the AI processor. Both the connection technology and a low and positive R _DS(on) temperature coefficient enable excellent performance under operating conditions with higher junction temperatures.

Engineering samples of the CoolSiC MOSFET 400 V portfolio are now available and will go into series production from October 2024 on. The latest generation of Infineon’s CoolSiC MOSFETs will be showcased at the Infineon booth at PCIM Europe 2024 in June.