INTERNATIONAL Rectifier, represented by Soanar Plus, has introduced the smallest control and synchronous MOSFET chip set for existing and next-generation VRM10.x high-current synchronous buck converters where small size, high efficiency and maximum thermal conduction are mandatory.
The IRF6608 control MOSFET has 8.5mΩ typical on-resistance (RDS(on)), while the IRF6618 synchronous MOSFET has 1.7mΩ typical on-resistance.
The new devices are housed in IR's DirectFET package. The IRF6608 is 50 per cent smaller than the standard SO-8 package, and is the first HEXFET MOSFET housed in the new double-side-cooled, surface-mount DirectFET "S" package.
The profile is 0.7mm, compared to 1.75mm for SO-8. In addition, the new IRF6608 has as much as 10 per cent better on-resistance, reduced gate charge (QG) and gate-to-drain charge (QGD) characteristics compared to similar control MOSFETs on the market, delivering over 2 per cent more overall efficiency, making it an ideal control MOSFET.
The IRF6618 has a typical on-resistance of 1.7mΩ and a maximum of 2.2mΩ, a 25 per cent improvement compared with similar devices on the market, and is ideal for the synchronous MOSFET application, where low conduction loss is most important. The IRF6618 can also be used for secondary side synchronous rectification in high current, isolated dc-to-dc converters.
The new chip set enables designers to make a very low profile power converter (0.98-inch) for 1U (1.75-inch height) rack sized server systems that meet VRM 10.x specifications.
The new chip set is also suitable for buck converters in servers and point-of-load converters in telecom and netcom systems.