Engineer Column

Five Engineers Talk About New Medium-Power Device ProductsPart 4 Power Diodes Achieve Improved Heat Dissipation Performance, Compactness through Adoption of PMDE Package


Good day, everyone. My name is Katagiri, and I’m with ROHM. This fourth article is about new power diode products adopting the PMDE package.

I’ll begin by briefly discussing the development background and history of the PMDE package. It goes without saying that demands for compact and energy-efficient electronic devices extend to all the components that make up the devices. Of course, this is true for diodes as well, and compact packages with better heat dissipation ability have been sought.

At ROHM, the PMDS package (DO-214AC/SMA package: 5.0×2.6×2.0 mm) and the PMDU package (SOD-123FL package: 3.5×1.6×0.8 mm) have long been used for power diodes with an average rectified current IO of 1 to 2 A. In order to boost heat dissipation performance, ROHM has adopted the even more compact PMDE package (2.5×1.3×0.95 mm), to assemble a full lineup of diode products even more appealing than the previous models.

Fig. 1 PMDE package is far more compact even with the same current rating due to improved heat dissipation performance

The heat dissipation performance of the PMDE package is enhanced by a backside electrode structure, achieving heat dissipation comparable to the PMDU package that is currently the mainstream with an IO of approx. 1 A. As a result, while maintaining the dissipation characteristics of the PMDU package, it was possible to reduce the footprint by 40%. New Schottky barrier diode (SBD), fast recovery diode (FRD), and transient voltage suppressor (TVS) products adopting the compact, high-performance PMDE package were developed, and are here introduced.

Power Diode Products Adopting the PMDE Package

Device Series name Features/Applications Main ratings
SBD RBxx8 series
  • ・Ultra-low IR
  • ・Optimal for use in high-temperature applications such as vehicles, industrial equipment, power supplies
  • ・Concerns of thermal runaway are alleviated, contributing to greater reliability
IO=1A to 2A
VR=30V to 150V
RBR series
  • ・Low VF
  • ・Optimal for uses in secondary side rectification of AC-DC, DC-DC circuits, freewheel devices, reverse connection protection
  • ・Low power consumption during rectification, contributing to energy saving
IO=1A to 2A
VR=30V to 60V
  • ・High-speed switching, low VF
  • ・Optimal for secondary rectification such as in appliance PFC circuits, car onboard chargers
  • ・Contributes to higher efficiency and lower losses of switching power supplies
TVS VSxxVUA1VWM series
  • ・Guaranteed same 200 W (10/1000 μs) as the conventional PMDU package
  • ・Optimal for surge voltage and ESD protection in vehicles, industrial equipment, and consumer equipment
  • ・Reduced concerns of product failure due to surge voltages, contributing to reliability
Voltage rank 5 to 33V
Development mainly of 33 to 150V products

These are, at present, the power diode products that use the PMDE package; hereafter a broader variety of models will be offered. In future, compactness and higher efficiency will be pursued simultaneously, continuing product development leading to energy savings. They will meet your expectations.

Thank you for your time today.

<Related Information>

Advantages of PMDE Compact Package with High Heat Dissipation for Automotive SBDs

Information on Downloading Technical Documents

Downloadable materials, including lecture materials from ROHM-sponsored seminars and a selection guide for DC-DC converters, are now available.

Download Technical Documents

Downloadable materials, including lecture materials from ROHM-sponsored seminars and a selection guide for DC-DC converters, are now available.