900-V MOSFETs Conquer The "Silicon Limit"

One challenge in MOSFET design is the “silicon limit.” Every doubling of voltage-blocking capability leads to a five-fold increase in RDS(on). Yet Infineon beats the silicon limit with the 900-V members of its CoolMOS family.

Don Tuite

March 17, 2008

One challenge in MOSFET design is the “silicon limit.” Every doubling of voltage-blocking capability leads to a five-fold increase in R_DS(on). Yet Infineon beats the silicon limit with the 900-V members of its CoolMOS family.

These devices exhibit 120-mΩ on-state resistances in TO-247 packaging, 340 mΩ in TO-220s, and 1.2 Ω in D-PAKs. That’s about 75% better than conventional 900-V MOSFETs. Looking at the figure of merit (on-state resistance times gate charge), they also boast values down to 34 Ω-nanocoulomb.

In practice, a designer could use one of the 900-V chips in a flyback power supply for an LCD TV in lieu of a pair of 600-V MOSFETs, saving energy as well as bill-of-materials cost. The 900-V rating also allows series-connection of photovoltaic panels, reducing cabling power losses and costs.

Samples are available now. The volume price for 120-mΩ devices in TO-247 packaging will be below $3.50 each.

Infineon

www.infineon.com

About the Author

Don Tuite

Don Tuite (retired) writes about Analog and Power issues for Electronic Design’s magazine and website. He has a BSEE and an M.S in Technical Communication, and has worked for companies in aerospace, broadcasting, test equipment, semiconductors, publishing, and media relations, focusing on developing insights that link technology, business, and communications. Don is also a ham radio operator (NR7X), private pilot, and motorcycle rider, and he’s not half bad on the 5-string banjo.