IR chipset eyes high-frequency dc-dc converters

International Rectifier (IR) has introduced a control and synchronous switching chipset for high-frequency dc-dc converters powering next-generation Intel and AMD processors.

Other applications include point-of-load (POL) dc-dc conversion in telecom and datacom systems.

The new chipset pair delivers 84.5 percent efficiency at 90A in a four-phase 1U (1.75-inch height) VRM outline system switching at 750kHz per phase, and 87 percent efficiency at 150A in an eight-phase embedded VRD10.2 design switching at 400kHz per phase.

The first device is the monolithic IRF6691 DirectFETKY, which integrates a Schottky diode and synchronous MOSFET into a single package. According to IR, this enables an efficiency improvement of 1.1 percent at 1MHz per phase at full load compared to other existing 20V synchronous FETs on the market when using the same control FET. The IRF6691 also features a typical RDS(on) of 1.2 milliohm at 10VGS (1.8 milliohm at 4.5VGS ) and a typical Qrr of 26nC.

The second device is the IRF6617 DirectFET HEXFET Control MOSFET that is engineered for control FET switching. It features a total gate charge of 11nC, delivering a 33 percent reduction in on-resistance times gate charge product of 87 milliohm-nC at 4.5VGS compared to previous 30V devices.

Both devices feature the company's patented DirectFET packaging technology that, according to IR, presents a whole new set of design advantages not previously delivered by standard plastic discrete packages. By deploying a new dual-side cooling design, the DirectFET power MOSFET family doubles the current handling capacity of high frequency dc-dc buck converters powering advanced processors.

The IRF6691 is priced at $1.49 each, while the IRF6617 is available for 87 cents each. Pricing for both devices is for 10,000-unit quantities.