ROHM’s New SBDs: Achieving Class-Leading* Reverse Recovery Time with 100V Breakdown Voltage by Adopting a Trench MOS Structure that Significantly Improves VF-IR Trade-Off

　　ROHM has developed 100V breakdown Schottky barrier diodes (SBDs) that deliver industry-leading reverse recovery time (trr) for power supply and protection circuits in automotive, industrial, and consumer applications.

　　Although numerous types of diodes exist, highly efficient SBDs are increasingly being used inside a variety of applications. Particularly SBDs with a trench MOS structure that provide lower VF than planar types enable higher efficiency in rectification applications. One drawback of trench MOS structures, however, is that they typically feature worse trr than planar topologies - resulting in higher power loss when used for switching.

　　In response, ROHM developed a new series utilizing a proprietary trench MOS structure that simultaneously reduces both VF and IR (which are in a trade-off relationship) while also achieving class-leading trr.

　　Expanding on the four existing conventional SBD lineups optimized for a variety of requirements, the YQ series is ROHM’s first to adopt a trench MOS structure. The proprietary design achieves class-leading trr of 15ns that reduces trr loss by approx. 37% and overall switching loss by approx. 26% over general trench-type MOS products, contributing to lower application power consumption. The new structure also improves both VF and IR loss compared to conventional planar type SBDs. This results in lower power loss when used in forward bias applications such as rectification, while also providing less risk of thermal runaway which is a major concern with SBDs. As such, they are ideal for sets requiring high-speed switching, such as drive circuits for automotive LED headlamps and DC-DC converters in xEVs that are prone to generate heat.

　　Going forward, ROHM will strive to further improve the quality of its semiconductor devices, from low to high voltages, while strengthening its expansive lineup to further reduce power consumption and achieve greater miniaturization.

　　SBD Trench MOS StructureThe trench MOS structure is created by forming a trench using polysilicon in the epitaxial wafer layer to mitigate electric field concentration. This reduces the resistance of the epitaxial wafer layer, achieving lower VF when applying voltage in the forward direction. At the same time, during reverse bias the electric field concentration is minimized, significantly decreasing IR. As a result, the YQ series improves VF and IR by approx. 7% and 82%, respectively, compared to conventional products.

　　And unlike with typical trench MOS structures where trr is worse than planar types due to larger parasitic capacitance (resistance component in the device), the YQ series achieves an industry-leading trr of 15ns by adopting a unique structural design. This allows switching losses to be reduced by approx. 26%, contributing to lower application power consumption.

　　Application Examples• Automotive LED headlamps • xEV DC-DC converters • Power supplies for industrial equipment

　　• Lighting

　　☆: Under development

　　* The TO-277GE package products released and sold by online distributors this time are rated for car infotainment and body systems. For each part number, we are preparing grades that can be installed in powertrains, etc. (using the same part number), with mass production scheduled to start in September 2024. (The packaging symbol after the above part numbers will differ)

　　Product Page and Related InformationApplication notes highlighting the advantages of these new products in circuits along with a white paper that showcases the features of each SBD series are available on ROHM's website. An SBD page is also available that allows users to narrow down product options by entering voltage conditions and other parameters, facilitating the selection process during design. Click on the URLs below for more information.

　　■ ROHM SBD Product Page

　　https://www.rohm.com/products/diodes/schottky-barrier-diodes

　　■ Application Notes

　　Advantages of YQ Series: Compact and Highly Power Conversion Efficiency Schottky Barrier Diodes for Automotive

　https://fscdn.rohm.com/en/products/databook/applinote/discrete/diodes/yq_sbd_automotive_an-e.pdf

　　■ White Paper

　　ROHM's SBD Lineup Contributes to Greater Miniaturization and Lower Loss in Automotive, Industrial, and Consumer Equipment

　　https://fscdn.rohm.com/en/products/databook/white_paper/discrete/diodes/sbd_lineup_wp-e.pdf

　　Online Sales Information

　　Applicable Part Nos: Refer to the above table.

　　Availability: December 2023

　　Pricing: $2,5/unit (samples, excluding tax)

　　The products will be sold at other online distributors as well.

　　Terminologytrr (Reverse Recovery Time)

　　The time it takes for the switching diode to switch from the ON state to completely OFF. The lower this value is, the smaller the switching losses.

　　Forward Voltage (VF)

　　A voltage drop that occurs when electricity flows in the forward direction from + to -. The lower this value is, the higher the efficiency.

　　Reverse Current (IR)

　　Reverse current generated when reverse voltage is applied. The lower this value is, the smaller the power consumption (reverse power loss).

　　Thermal Runaway

　　When a diode is conducted in the reverse direction, heat generated within the chip may exceed the heat dissipation of the package, causing IR to increase and eventually lead to destruction, - a phenomenon called thermal runaway. For SBDs with high IR values, thermal runaway is especially likely to occur, so care must be taken when designing circuits.