Product category:
Discrete Power Devices
News Release from: International Rectifier | Subject: 300V FREDs
Edited by the Electronicstalk Editorial
Team on 07 September 2001
300V diodes provide ideal performance
for PSUs
International Rectifier has expanded its fast recovery epitaxial diode (FRED) family to include 300V ultrafast diodes.
International Rectifier has expanded 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 optimised for 48V switch-mode power supply systems for telecomms and datacomms applications
This article was originally published on Electronicstalk on 15 Feb 2001 at 8.00am (UK)
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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 an 18% reduction in power losses when compared in-circuit to the industry best 400V ultrafast diode.
Further reading
MOSFETs improve power density on both sides
New from International Rectifier are two TO-220-packaged HEXFET power MOSFETs that maximise power density and performance in primary- and secondary-side DC/DC convertor circuits.
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With high radiation hardness and unparalleled single event effect (SEE) immunity, International Rectifier's new R5 MOSFETs are well suited for systems that must survive penetrating gamma rays.
IR's 300V ultrafast diodes run up to 4C cooler than the best performing 400V ultrafast diode, resulting in increased reliability which is critical to power supplies used in power telecomms and datacomms systems.
In 48V-input power convertors, the required breakdown voltage in the output rectification stage is in the 200 to 300V range.
As 300V-rated diodes were not available on the market until recently, designers typically use 400V diodes to ensure an adequate safety margin, without adding a snubber circuit.
Unfortunately, 400V devices have higher forward conduction and switching losses than devices with lower voltage ratings, such as 200V diodes.
Designers 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.
The 300V rating of IR's new FREDs provides a sufficient safety margin for 48V output circuits, yet eliminates the snubber circuit required by 200V diodes.
The new 300V diodes optimise 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 their manufacture ensures ultrafast and soft recovery characteristics, which are critical at high frequencies and for reducing the size of bulky magnetic components.
IR's new 300V ultrafast diodes can replace 400 or 200V devices for increased convertor efficiency, thereby reducing heat sink size or increasing power density within the same footprint in a circuit upgrade.
Higher efficiency also translates into lower temperature and increased reliability.
Available immediately, the new 300V ultrafast diodes complement IR's wide selection of 200 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 datacomms/telecomms market.
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