ROHM Expands its Lineup of Automotive, Space-saving PMDE Package Diodes

April 28, 2022 by Gary Elinoff

Measuring a scant 2.5 by 1.3 mm, the new diodes further miniaturization in automotive applications while maintaining high performance.

In the automotive environment, saving space is imperative. 

Every square millimeter is precious, because there is always another app to add or an added level of security to establish. But the rub is that the automotive environment is one of the harshest there is, so designers can’t sacrifice durability to enhance miniaturization. What’s more, the new world of electric vehicles (EVs) demands only the highest-performing components.


EVs, such as the PS2 from Polestar pictured here, demand the highest-performaning components. Image [modified] used courtesy of Kenny Leys/Unsplash


Enter ROHM’s PMDE package, whose lineup has now expanded to include 10 new Schottky barrier diodes, two fresh fast recovery diodes, and two additional transient voltage suppressor diodes, the company announced Tuesday. 


The PMDE Package

ROHM’s PMDE package features an expanded backside electrode. This serves to more efficiently facilitate the transfer of excess heat away from the component and into the safe recesses of the PCB. The result of this diffusion is that the component can more effectively dissipate heat, and thereby equal or better the performance of significantly larger packages.

For example, ROHM asserts that the 2.5 x 1.3 mm PMDE package achieves the same electrical characteristics as those of the far larger, 3.5 × 1.6 mm, SOD-123FL package.

Whereas the old-school SOD-123FL package, as illustrated below, dissipates heat through the rather inefficient pathway provided by the lead frame, the PMDE dissipates heat through the broader highway provided by the backside electrode. That enhanced ability to transfer heat, of course, translates directly to the device’s increased performance in handling current surges. 


The PMDE dissipates heat through the broader highway provided by the backside electrode. Image [modified] used courtesy of ROHM

And that’s in a package sporting a required mounting area 42% smaller, the company says, with a connection whose mechanical strength is 1.4 times higher. This added strength serves to increase mounting reliability by reducing the risk of solder cracking while the board is under mechanical stress. 


The PMDE's increased mounting strength reduces the risk of solder cracking. Image [modified] used courtesy of ROHM

Below, we briefly describe ROHM’s new PMDE-incorporated components packing in those benefits. 


Schottky Barrier Diodes

ROHM has added 10 new PMDE-housed models to its existing RBxx8 series of Schottky barrier diodes (SBD). The new devices feature breakdown voltages ranging from 30 to 150 V, together with reverse currents ranging from 0.3 to 1.0 µA.

These devices are aimed at rectification and switching.


Fast Recovery Diodes

The RFN series now includes two new fast recovery diodes (FRD) available in PMDE packages. These fresh RFN offerings, the RFN1VWM2STF and the RFN2VWM2STF, feature withstand voltages of up to 800 V, reverse recovery times of 14 ns, peak forward surge currents of 20 A, and reverse voltages of 200 V.

In addition, the former sports a maximum forward current of 1 A and a maximum forward voltage of 0.93 V. The latter has equivalent specifications of 2 A and 0.99 V.

These units are aimed at switching.


Transient Voltage Suppressor Diodes

Transient voltage suppressor diodes (TVS) are designed to absorb sudden voltage surges. Here, ROHM has included two new PMDE-housed members in its VS series, which feature a peak pulse power rating of 200 W and power dissipation of 1 W. 

TVS diodes are aimed specifically at surge protection.


Additional Considerations

Targeted at the automotive environment, the 14 new PMDE-packaged diodes are, naturally, all AEC-Q101 qualified.


Feature image used courtesy of Evgeny Tchebotarev/Unsplash