Buck MOSFET chip

International Rectifier has introduced the IRF7821 and IRF7832 synchronous buck converter chip set designed to increase battery life in notebook computers.

Other applications for the HEXFET MOSFETs include buck converters for computer server power systems and graphics cards, as well as point-of-load converters in telecom and datacom systems.

For maximum MOSFET efficiency, the goal is to reduce device on-resistance, or RDSon, to minimise conduction loss, and to reduce gate charge (Qg) and gate-to-drain charge (Qgd) to minimise switching loss.

IR's stripe trench HEXFET MOSFET technology enables devices characterised with reduced RDS(on), Qg and Qgd, resulting in more than 1% increased system efficiency compared with other systems.

In addition, reverse recovery charge, Qrr, has been reduced to minimise reverse recovery loss.

The IRF7821 has 10nC Qg and 2.5nC Qgd, making it suitable as a control MOSFET, and features a 40% reduction in gate charge compared with other devices.

The IRF7832 has 4.0 mohm maximum RDS(on) at 10 VGS, making it suitable for the synchronous MOSFET application, and delivers a 25% improvement in device on-resistance compared with other devices.