International Rectifier Introduces Two New MOSFETs, the IRFB42N20D and IRF3703

International Rectifier (IR, El Segundo, CA) released two new TO-220-packaged HEXFET power MOSFETs, the IRFB42N20D and the IRF3703. The new devices can be used to replace TO-247-packaged devices and were designed for high-efficiency, 48V-input isolated dc/dc converters for telecom and datacom systems. 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 200V MOSFET with a gate charge of 103nC. IR claims that, at full load (40A), the IRFB42N20D can deliver better than one percent efficiency improvement over the competing solution in the larger TO-247 package.

"The one percent-plus efficiency increase using the new primary-side MOSFET is significant since it is achieved in a smaller package. Increasing power density requirements drive circuit designers to use higher operating frequencies. The low gate charge of the IRFB42N20D is the key enabling factor for faster switching speeds and more efficiency in a smaller package," said Carl Blake, technical marketing, dc/dc sector.

The 30V IRF3703 has 2.8 milliohms Rds(on). IR claims that, for sub-3.3V applications, this device improves efficiency in secondary-side synchronous rectification circuits.

"In multiple-output, isolated converters, circuit board layout is often simplified if the same device can be used in the secondary stages. The IRF3703 is an excellent choice for secondary-stage applications, and reduces bill of material line items, as well as time-to-market," added Blake.

Pricing for the IRFB42N20D is $1.71 each in 10,000-unit quantities. The IRF3703 is priced at $1.74 each in the same quantities.