EL SEGUNDO, CA. March 1999 - International Rectifier (IRâ ), the power expert, now offers an advanced HEXFETâ power MOSFET chip set for DC-DC converters to meet Intel's Mobile Power Guidelines 2000 specification. This new pair of low-voltage HEXFET power MOSFETs, designated the IRF7811 and IRF7809, is the industry's first solution to achieve the 90 percent overall efficiency for the CPU core plus peripheral DC-DC converters recommended by Intel's Mobile Guidelines 2000. The new HEXFET chip set does so without paralleling devices, maintaining the smallest possible component footprint for the power supplies, despite increased current requirements.

Intel's Mobile Power Guidelines 2000 represents a challenge to the mobile PC industry and all suppliers to meet recommended power budgets that will enable future higher system performance within existing thermal envelopes. Without these efforts, it's predicted that PC performance will be limited, or run-time and laptop temperatures will literally reach levels unacceptable to the consumer. IR has taken on this challenge and is the first to demonstrate a power supply that meets these targets.

"Intel applauds IR's efforts to meet the recommended power specification for mobile power supplies," said Daniel Lenehan, Intel Corporation, director of mobile platform architecture. "As others follow with similar efforts to implement lower power solutions, the industry can continue to deliver increasingly more desktop performance and features to mobile PCs."

"Our new synchronous rectification chip set is a continuation of the commitment we made last year in developing efficient low-voltage power solutions for processor applications," said Gene Sheridan, vice president of the processor power group at IR. "Using our knowledge of low-voltage DC-DC converter applications and their synchronous rectification topology, we modeled and then optimized our MOSFET technology to maximize system performance demanded to power future mobile CPUs operating as low as 1.3V and in excess of 12A power consumption. We developed two new silicon technologies that deliver devices with the best overall performance within the application-specific power supply topology." Sheridan indicated that the key to the new HEXFET chip set was a clear understanding of the performance requirements for each device in a high frequency synchronous buck converter. He explained, "For example, we chose to implement the synchronous MOSFET (IRF7809) that carries the bulk of the current using an advanced trench process, to minimize R_DS(on) and resulting conduction losses while increasing Cdv/dt immunity to prevent spurious turn-on and resulting efficiency loss. In addition, we implemented the control MOSFET (IRF7811) using an advanced planar process to offer low gate charge (Q_switch) and facilitate efficient high-frequency switching operation."

"By selecting the silicon design with lower R_DS(on) for the low-side MOSFET and tailoring the charge characteristics of the high-side MOSFET, we can achieve optimal power supply efficiency in a notebook DC-DC converter using the next generation of Intel processors," Sheridan stated. "And we can guarantee this performance in the real world within the pricing expectations of our customers."

Sheridan noted that heat has become a particularly challenging application factor, with peak currents for the new upcoming Intel devices forecasted to be 12A or greater. So new packaging technology to improve thermal efficiency is also required in addition to low R_DS(on).

"Our new CopperStrap^TM interconnect technology provides the thermal characteristics required to sink heat off the chip more efficiently than ever before, reducing junction operating temperatures by as much as 20 percent and eliminating the need for paralleled devices," he noted. "The IRF7811 offers a typical on-resistance of 9mW at V_GS=4.5V with ultra-low gate charges for low switching losses with Q_g=17nC and Q_switch=5.8nC. The IRF7809 offers the lowest on-resistance ever achieved at V_GS=4.5V in an SO-8 with only 6m W typical ratings along with a total gate charge characteristic, Q_g, of 60nC."

The new IR MOSFET chip set for DC-DC converters in next-generation notebook PCs is available in industry standard SO-8 surface mount packages. Samples are available from stock, with production quantities commencing in June 1999.