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FETs Maximize Efficiency In Targeted DC/DC Topologies

Feb. 1, 2001

This series of topology-specific HEXFET power MOSFETs maximize efficiency in targeted isolated and buck dc/dc converters. The new 100V-rated IRF7473 in an SO-8 package has been designed for the primary stage of two-stage isolated converters with 48V input, 1.6V output at 60A. The IRF7473 is optimized for low device on-resistance and low gate charge, and improves efficiency by 0.4% compared to the top competitors. Peak efficiency ratings as high as 90% can be achieved when the IRF7473 is matched with the new IRF7822 synchronous rectification MOSFET. The new 40V-rated HEXFET MOSFETs in the SO-8 package are designed to work with a 28V bus in notebook computers. The raw battery voltage is distributed through the system in a power plane and is point-of-load regulated down to the required voltage. The 40V-rated devices equips designers with a choice between two control MOSFETs, the IRF7468 and IRF7469, and two synchronous MOSFETs, the IRF7470 and IRF7471. Synchronous buck topologies using the IRF7468 and IRF7470 reach an efficiency of 82% in 28V, 1.3V output converters running at 300 kHz. Four additional MOSFETs (IRF7453, IRF7450, IRF7451, IRF5801) are optimized for significantly reduced on-resistance, while keeping gate charge to a minimum level. Pricing for the new MOSFETs begins at $0.42 each in 10,000-unit quantities.


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