IR Intros IRF6646/IRF6635 DirectFET Chipset

International Rectifier Corp. (IR, El Segundo, CA) introduced a new DirectFET™ chipset, the IRF6646 and IRF6635, which maximizes dc bus converter efficiency, when used with IR’s IR2086S full-bridge bus converter IC. The chipset enables a bus converter solution capable of delivering 336 W with 97% efficiency. The IRF6646 and IRF6635 are optimized for 48 V regulated and 36 V to 60 V input-bridge topologies in isolated dc-dc bus converters; synchronous buck, non-isolated dc-dc topologies; 18 V to 36 V input forward and push-pull converters for mobile communications; and secondary-side synchronous rectification in regulated output, isolated dc-dc applications.

The new chipset solution consists of six MOSFETs (four in the primary and two in the secondary side) and a single IC, yielding a 46% reduction in power semiconductor part count. In addition, isolated bus converter dc-dc applications made with the chipset achieve 29% reduced board space and operate with as much as 1.5% better efficiency. The new IRF6646 80 V MOSFET has a maximum on-state resistance of 9.5 mΩ and is tailored for primary-side bridge topologies, while the IRF6635 30 V MOSFET has a maximum on-state resistance of 1.8 mΩ and is optimized for secondary-side synchronous rectification. The MOSFET pair combines with the IR2086S full-bridge dc bus converter IC and the IRF6608 30 V DirectFET MOSFET, used as a secondary-side gate clamp.

The new 80 V IRF6646 and the 30 V IRF6635 DirectFET MOSFET synchronous buck chipset is now available. Pricing is $1.37 each for the IRF6646 and $1.50 each for the IRF6635, both in 10,000-unit quantities.