STM32WL5M, the 1st LoRaWAN-certified ST module democratizes sub-GHz applications in a big way!
The STM32WL5M is ST’s first LoRaWAN-certified module and the latest chapter in our sub-GHz democratization story. Indeed, ST started with STM32WLE, the first wireless MCU with an embedded multi-modulation radio. Then, engineers got two cores in the STM32WL5, one of them for the wireless stack, thus optimizing the creation of sub-GHz applications. Then, we released schematics, reference designs, and integrated power devices that are already fine-tuned for the STM32WL to further simplify design operations. Today, ST is adding a new twist with a module that integrates all these components into one package. We’ve already shown the STM32WL5M at conferences in 2023, and feedback has been very positive. Let’s understand why.
Why a module?
Practical conception
The STM32WL5MC is our first LoRaWAN-certified module and the first to support two output powers thanks to its two power amplifiers. Hence, coupled with the wide frequency range supported by its STM32WL5x, the module can work in Europe, Americas, and Asia. Yet, despite all this, the device is still one of the smallest at 10 mm x 10 mm. Consequently, the module makes designing a sub-GHz application far more practical as it enables engineers to enjoy a comprehensive solution in a small package without having to deal with the complexity of creating it.
Practical implementation
Behind the scenes, we know many customers eye such modules for lower volume products, although numerous exceptions exist. ST thus aimed to make the STM32WL5M even more practical for products with smaller manufacturing objectives. For instance, we’ve ensured that it fits a two-layer PCB, requires no external passive components to enable features, and already includes an internal SMPS. Put simply, it simplifies the bill of materials as well as the PCB layout and helps significantly reduce the time to market, which is essential when building a lower-volume unit. Some versions (with part numbers ending in S) even include an STSAFE secure element to make it more practical for companies with critical security requirements.
Practical certification
As is traditional in a sub-GHz module, engineers only have to focus on the external antenna and the software stack. Because of the wireless requirements associated with such frequency bands, it is not feasible to include the antenna inside the package, like in the STM32WB modules. However, ST still aims to make the STM32WL5M more practical than competing solutions. As a result, we offer a reference design and documentation to help engineers easily kickoff their hardware PCB design. Additionally, the antenna-matching filters are already in the module. Furthermore, the STM32CubeWL firmware package includes a certified stack and example code, making the final certification process more straightforward.
