TO247 4-pin Package for CoolMOS MOSFETs offers significant efficiency gains in hard-switching topologies

Infineon Technologies introduced a TO 247 4-pin package, where the added fourth pin acts as a Kelvin source to effectively reduce the parasitic inductance of the source lead of the power MOSFET. The efficiency benefit will be highest in various hard switching topologies such as Continuous Conduction Mode Power Factor Correction (CCM PFC), Boost and Two Transistor Forward (TTF). The new package offers improved efficiency by reducing switching losses by up to 8 percent. This equates to 5W lower power dissipation on the MOSFET in a CCM PFC running at 1.2KW, which means 0.4 percent extra full load efficiency compared to the same MOSFET in the standard 3-pin TO 247 package. The new TO 247-4 is available from two companies: both Infineon and STMicroelectronics are introducing this package providing customers with a high-quality alternative source. "The latest generation of Superjunction MOSFETs like our new CoolMOS C7 is able to switch several hundreds of volts and several tens of amperes within a few nanoseconds. To reach the full benefit of the chip technology the package is an important factor to set up an appropriate system environment which is crucial to reach the next level of energy efficiency," said Jan-Willem Reynaerts, Product Segment Head of High Voltage Power Conversion at Infineon Technologies. "This new TO 247-4 pin package for High Voltage MOSFETs, today being introduced by Infineon as well as STMicroelectronics, is setting new energy efficiency standards." An additional benefit of the Kelvin source configuration in the TO 247-4 is the ease of use for the PCB layout due to its new pin arrangement with the exposed drain and the source between gate and drain. This reduces the critical drain to gate coupling, which often causes gate oscillations at turn off with high dv/dt rates of the Drain-Source Voltage (V DS). Furthermore, the increase of creepage distance between drain and source improves system reliability. The new package is optimized for high power applications like server, telecom and solar. Samples of the TO 247-4 package are available now, volume production will start in the third quarter 2013. Infineon