ROHM Launches PMDE Package Diodes for Automotive Applications

ROHM announces the addition of 14 new models to its PMDE package (2.5 mm × 1.3 mm) lineup meeting the requirements for smaller protection and switching circuits.

Diodes are used for rectification, protection, and switching circuits in a wide range of applications such as automotive, industrial, and consumer fields. Additionally, there is an increasing need to reduce package size to minimize mounting area. At the same time, higher performance is required to reduce power consumption.

However, when decreasing package size the surface area of the backside electrode and mold also becomes smaller, resulting in lower heat dissipation. To solve this disadvantage, ROHM’s PMDE package improves heat dissipation performance by expanding the backside electrode and optimizing the heat dissipation path.

This achieves the same electrical characteristics as those of conventional packages in smaller package sizes.

ROHM’s proprietary compact PMDE package features a land pattern equivalent to that of the conventional SOD-323 type. Reviewing the backside electrode and heat dissipation path allowed ROHM to achieve the same electrical characteristics (i.e. current, withstand voltage) as the standard SOD-123FL package (3.5 mm × 1.6 mm) in a smaller package size, contributing to board miniaturization by reducing mounting area by approximately 42%.

Furthermore, mechanical strength is around 1.4 times higher than that of the SOD-123FL, reducing the risk of solder cracking when stress is applied to the board, ensuring greater mounting reliability.

The PMDE package lineup consists of 8 models in the RBxx8 series of Schottky barrier diodes, 2 models in the RFN series of fast recovery diodes, and 2 models in the VS series of transient voltage suppressors. A variety of circuit applications can be achieved with compact diodes. Going forward, ROHM will strive to further improve the quality of its semiconductor devices, from low to high voltages while strengthening its distinctive lineup to further reduce power consumption and achieve greater package miniaturization.

Key features of the PMDE Package

1. Significantly improved heat dissipation achieves a 42% smaller mounting area

Generally, semiconductor components dissipate heat generated into the air or through the substrate. However, when decreasing package size the surface area of the back of the electrode and mold also becomes smaller, resulting in lower heat dissipation. The PMDE package, to solve this problem, increases the back electrode area to facilitate the heat dissipation path from the lead frame to the substrate. The result is significantly improved heat dissipation performance, achieving the same electrical characteristics as the standard SOD-123FL package (3.5 mm × 1.6 mm) within a smaller 2.5 mm × 1.3 mm size. This translates to a 42% smaller mounting area, making it ideal for automotive applications where higher component density is needed.

2. Ensures higher reliability compared to conventional packages

The PMDE package achieves a mounting strength of 34.8 N, approximately 1.4 times higher than that of the SOD-123FL package, by increasing the area of the metal portion ensures a larger backside electrode area. This reduces the risk of solder cracking when stress is applied to the board, contributing to greater reliability. High surge current withstand capability (IFSM) is also achieved by adopting a wire-free structure whereby the chip is directly sandwiched between frames. The resulting high surge current withstands capability (IFSM) provides superior resistance to the destruction caused by high instantaneous currents, such as during vehicle start or abnormal device operation.