El Segundo, CA. May 2000 - International Rectifier (IR^®), the power experts, now offer a MOSFET chipset optimized for use in advanced multiphase DC-DC converters operating in excess of 1 MHz. These new devices can accommodate the high power levels, fast transient response and compact size required to facilitate the design of more efficient power supplies for today's advanced processors. These include the recently announced 1GHz Intel Pentium III and AMD Athlon processors.

The new IR chipset includes the IRLR8503 control FET and the IRLR8103 synchronous FET for use in single-phase or multi-phase synchronous buck circuits. Multiphase conversion is a relatively new technique that interleaves parallel converters out of phase to reduce peak currents through each phase. Because peak currents per phase are reduced, surface mount MOSFETs can replace heat-sink mounted devices, even in converters capable of providing more than 30A. Furthermore, the size of the inductors and number of capacitors can be dramatically reduced by increasing the operating frequency of these converters to the 1MHz range.

"Our new IRLR8503 control FETs offer the best Q_SWITCHxR_DS(on) figure of merit available in a D-Pak, providing designers with the best possible switching characteristics for high frequency operation," said John Lambert, product marketing engineer for the Processor Power Group at IR. "Similarly, our new IRLR8103 synchronous FETs deliver an R_DS(on) of just 8 mOhms at 4.5 Vgs and Cdv/dt immunity to efficiently accommodate high current requirements. Using both of these devices, we have demonstrated multiphase converters supplying 60A with a full load efficiency of 80 percent, while operating at 1 MHz per phase."

Lambert noted that this new MOSFET chipset is part of a continuing IR initiative to develop the advanced components needed to keep designers of buck and isolated DC-DC converters up to speed with component solutions for today's advanced systems.

Samples for the IRLR8103 and IRLR8503 MOSFET chipsets for multiphase DC-DC converters are available online at DC2DC.irf.com. Production of these new devices is scheduled to commence in May 2000, with prices starting at $1.35 per MOSFET pair in quantities of 100,000.