1200V, 325A silicon carbide module in a new, low-inductance format

May 16, 2016 // By Graham Prophet
To realise the potential of its silicon carbide power devices, Wolfspeed (Cree) has designed a completely new format of half-bridge module that has an inductance of 5.5 nH; to further minimise current paths and simplify the use of the package, it comes with a physically-matching new design of driver board.

This all-SiC module is the first fully-qualified commercial power module from Wolfspeed’s Fayetteville, Arkansas location: it allows systems designers to realize lighter weight systems that are up to 67% smaller by achieving efficiencies of over 98% and improvements in power density of up to 10 times compared to systems built with silicon-based technologies. The company adds, “Our 2015 acquisition of Arkansas Power Electronics International (APEI) enabled our team to deliver this advanced power module design on an aggressive timeline by combining leading-edge SiC device technology with … packaging innovation. The resulting module is the first of many products that promise an accelerated disruption of the power electronics market.”


The module supports high-frequency, ultra-fast switching operation; with the zero reverse-recovery current associated with SiC diodes, and zero turn-off tail current from the MOSFETs. It operates in a normally-off, fail-safe device operation mode, allows for ease of paralleling and is built on an AlSiC baseplate with Si3N4 AMB insulator, enhancing ruggedness with respect to thermal cycling.


Compared to conventional silicon IGBT power modules, or even previous generations of SiC MOSFET modules, the new module will offer significantly higher power density for applications in which volume and weight are critical limitations. Operating at a higher switching frequency without any compromise in system efficiency means a reduction in the number and size of magnetic and passive components required for the balance of the system. The superior thermal characteristics of SiC devices, along with the packaging design and materials, enable the module to operate at 175°C, which is a key advantage for many industrial, aerospace, and automotive applications.


Module inductance is reduced to 5.5 nH, compared to competitive power products at 15 nH; the CAS325M12HM2 module is configured in a half-bridge topology comprised of seven 1.2 kV 25 mΩ C2M SiC MOSFETs and six 1.2kV 50A Z-Rec Schottky diodes.

The companion gate driver (CGD15HB62LP) is specifically designed for integration with the module