EL SEGUNDO, CA. August 2001 - International Rectifier (IRŪ, NYSE: IRF) expands its fast recovery epitaxial diode (FRED) family to include 300V ultrafast diodes. The new 300V family includes 8A (8ETH03), 15A (15ETH03) and 30A (30EPH03, 30CPH03) devices optimized for 48V switch-mode power supply (SMPS) systems for telecom and datacom applications.

The new 300V ultrafast diodes feature 50% lower reverse recovery current (IRRM) compared to the best competitive device. In addition, the new IR devices have smaller forward conduction losses (lower VF) and lower reverse recovery time (TRR) compared to 400V devices. The improvements in IRRM, TRR and VF result in best in class performance with 3% lower losses than the industry best 300V device and up to a 18% reduction in power losses when compared in-circuit to the industry best 400V ultrafast diode. IR's 300V ultrafast diodes run up to 4°C cooler than the best performing 400V ultrafast diode resulting in increased reliability which is critical to power supplies used to power telecom and datacom systems.

In 48V input power converters, the required breakdown voltage in the output rectification stage is in the 200V to 300V range. Since 300V rated diodes were not available in the market until recently, designers typically use 400V diodes to have an adequate safety margin, without adding a snubber circuit. Unfortunately, 400V devices have higher forward conduction and switching losses than devices with lower voltage rating such as 200V diodes.

Designer can use 200V diodes with the addition of a snubber circuit to reduce over-voltages across the diode. However, the snubber circuits needed when using 200V diodes increase circuit complexity and introduce power losses across the snubber output resistor.

International Rectifier's new FREDs have a breakdown voltage of 300V. The voltage rating provides a sufficient safety margin for 48V output circuits, yet eliminates the snubber circuit required by 200V diodes. The new 300V diodes optimize the balance between forward voltage drop and reverse recovery time. IR's devices also show a softer recovery wave shape. The Pt diffusion process employed in the manufacture ensures ultrafast and soft recovery characteristics, which are critical at high frequencies and also to reduce the size of bulky magnetic components.

Stephen Oliver, International Rectifier Marketing Manager for AC-DC Sector, said, "IR's new 300V ultrafast diodes can replace 400V or 200V devices for increased converter efficiency. More efficiency can reduce heat sink size, or increase power density within the same footprint in a circuit upgrade. More efficiency also translates in lower temperature and increased reliability."

IR's 300V ultrafast diodes complement the wide selection of 200V and 400V ultrafast diode offerings for traditional output rectification designs. Generally, two to four diodes are used in the output rectification circuit in a single power supply for the datacom/telecom market.

Pricing and Availability

The new 300V ultrafast diodes are available immediately. Pricing ranges from US $0.56 to $1.35 each in 10,000-unit quantities.

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