The new SMB15F family of 1,500 W transient-voltage-suppression diodes in an SMB Flat package is now qualified. The smaller package offers a footprint reduction of 50% compared to its SMC equivalent. Beyond the space gain, the devices are also cost-effective, which compounds the savings companies. Moreover, the smaller size will open the door to increased power density and greater efficiency. Indeed, the SMB15F series has a leakage current that’s about five times lower than the competition. Hence, the 1,500 W devices are already being evaluated in 5G equipment, among other applications.
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Table of Contents
- Why Did ST Make Two SMB15F Series, the SMB15FxxA and SMB15FxxAY?
- Why Does the Industry Need 1,500 W TVS in SMB Flat packages?
- Will the SMB15F Replace the 1,500 W TVS in SMC Packages?
- Why Did We Have to Wait for 2021 to Qualify 1,500 W TVS in SMB Flat Packages?
- How Do SMB15F Devices Compare to SMC Alternatives?
- Are There Other TVS devices in Small and Flat Packages?
Why Did ST Make Two SMB15F Series, the SMB15FxxA and SMB15FxxAY?
The part numbers ending with an “A” are for industrial applications, while the ones ending in “AY” are automotive-grade. The silicon is identical, but the “AY” models undergo more rigorous testing and tracing to obtain an AEC-Q101 auto-grade qualification. Each series currently has 26 variations based on the device’s standoff voltage. For instance, the SMB15F11AY is the auto-grade version for our 1,500 W model with a standoff voltage of 11 V. Each series starts with a standoff voltage of 5 V and can go as high as 64 V.
Why Does the Industry Need 1,500 W TVS in SMB Flat packages?
ST first sampled its SMB15F devices in 2019, which was also symbolic because it inaugurated various initiatives in essential markets. For instance, the 2019 Industrial Summit in China showed the increasing need for greater power density. Robots were using IGBT drivers, and silicon carbide was transforming electric vehicles. Fast forward to 2021; the Industrial Summit showcased more devices needing high-powered protection in small packages. From drones to smart building solutions and e-bikes, protecting sensitive components from surges is ever more critical. And as products get smaller while consuming more power, it is imperative to use smaller and flatter packages.
Will the SMB15F Replace the 1,500 W TVS in SMC Packages?
The current 1,500 W devices will continue to exist. We understand that some companies take time to switch to a new package. Once teams qualify a device and use it in their designs, it is natural to get as much from it as possible. However, we are also aware of the market realities that clamor for this highly cost-effective SMB Flat package. Hence, our goal is to help teams transition from SMC to SMB Flat packages. For instance, many SMC models have an equivalent version in the SMB15F family to help engineers keep their PCB as long as they have a compatible footprint.
Why Did We Have to Wait for 2021 to Qualify 1,500 W TVS in SMB Flat Packages?
It’s easy to overlook the technical complexities inherent to a transition from an SMC to an SMB Flat package, but it’s because we have been mastering the assembly lines of our TVS products for more than 30 years that we can lead the industry in offering this modern and cost-effective solution.
SMB15F devices represent a new chapter in the history of TVS diodes. Our SMC series is more than 20 years old, and we can expect the SMB Flat models to know a similar success because they also increase reliability beyond lowering costs. Like with the previous generation, the SMB15F are so robust that we offer industrial-grade and automotive-qualified versions (AEC-Q101) of the same die. We also increased our production capabilities to ensure that companies that want to jump on the bandwagon early can do so with confidence, knowing that they will meet their customers’ demands.
How Do SMB15F Devices Compare to SMC Alternatives?
The benefits of a flatter package aren’t always evident to managers or less experienced engineers. For instance, the image below compares a similar device in an SMC and SMB Flat package. The blue curves show that voltage is nearly identical during clamping, with a difference of only 0.3 V between the two due to dispersion. Similarly, the current inrush (pink curve) also displays similar characteristics. Hence, the document proves that SMB15F devices enable lower costs and smaller PCBs without sacrificing their protective capabilities.
Are There Other TVS devices in Small and Flat Packages?
ST also offers 400 W and 600 W transient-voltage-suppressors in SMA Flat and SMB Flat. The devices are pin-to-pin compatible with the previous generation, and the 600 W model is available in both SMA Flat and SMB Flat to help some companies transition from a traditional SMB device to SMA Flat. Indeed, the SMB Flat devices provide an intermediary step. In many cases, manufacturers already have pick-and-place machines compatible with thinner devices, but engineers often ignore these components to focus on other aspects of their designs. By making 1,500 W TVS diodes in flatter packages more accessible, designers can transition to more cost-effective solutions without diverting their focus away from the other parts of the PCB.
