MOSFETs Improve DC/DC Converter Power Density

Specifically designed for high-efficiency, 48V-input isolated dc/dc converters for telecomm and datacomm systems are two new TO-220 packaged HEXFET power MOSFETs. The devices maximize power density and deliver maximum performance in primary- and secondary-side dc/dc converter circuits and they can replace larger TO-247 packaged devices. The IRFB42N20D is optimized for primary-side circuits, while the IRF3703 is tuned for secondary-side, sub-3.3V output applications. The IRFB42N20D is a 200-V MOSFET with a low gate charge of 103 nC. The gate charge reduces switching losses so significantly that it is said to outperform similar MOSFETs in the larger TO-247 package. For sub-3.3V output applications, the IRF3703 has optimized characteristics that improve efficiency in secondary-side synchronous rectification circuits. Pricing is $1.71 for the IRFB42N20D and $1.74 for the IRF3703, each/10,000.