The chip set consists of the IRF6621 control MOSFET and the IRF6612 synchronous MOSFET, with each device tailored to maximize performance in their role within a synchronous DC-DC buck converter circuit. Control MOSFETs have reduced switching losses, while synchronous MOSFETs have low conduction losses (low on-resistance), and low reverse-recovery charge. The new chip set achieves above 87% efficiency at 18A per phase and exceeds 90% efficiency at a mid-current level of 10A per phase.

“The board space savings alone of two DirectFET MOSFETs versus three SO-8 devices is almost 50%, and this new chip set is an excellent value for customers seeking very compact and efficient switching in mid-range, 14 to 18 amp power converter applications,” said Jeff Sherman, International Rectifier, Senior Marketing Manager, Portable Computing Solutions.

The IRF6621, with its very low Qg and Qgd of only 11nC and 3.8nC respectively, is best suited as a control FET. The IRF6621 shows a 15% reduction in on resistance-gate charge (108mOhm-nC) compared to the previous 30VN device (IRF6608, 128mOhm-nC). The IRF6621 is housed in a small can (SQ) DirectFET package, about 38% smaller than an industry-standard SO-8.