ST MICROELECTRONICS LAUNCHES SIGFOX 0G TECHNOLOGY-COMPATIBLE CHIPSET

STM32WL3x comes with a new ultra-low-power radio and an updated S2-LP transceiver to democratize new sub-GHz apps.

What does this mean to Developers, Device & Solution Makers?
More cost-effective features-rich Sigfox-based devices and solutions can be created using this chipset, targeting smart metering, asset management, smart cities as well as various low-power IoT applications. Developers get a shortcut from PoC to final design thanks to hardware features targeting their applications, like the LC Sensor Controller and a familiar software ecosystem.

What are the notable highlights?
An innovation unique to the STM32WL3x is the presence of two radios, one dedicated to a low-power wake-up function. Designed for proximity detection, it only supports OOK modulation, has a continuous receiving mode (RX), and is compatible with a wide frequency band from 100 MHz to 2.4 GHz. As a result, it consumes a meagre 4.2 µA, significantly less than what traditional radio consumes by an order of magnitude. For comparison, the regular sub-GHz module of the STM32WL3x needs 5.6 mA in RX mode, which is already considered an efficient device by today’s standards.

In simpler words: You can now design geofencing solutions that consumes way less power than before.

UnaBiz is working with developers to design new use-cases around STM32WL3x low-power wake-up function. Solutions designers who wish to create products with this function are encouraged to reach out to UnaBiz to discuss the features and their possible implementations.

The regular radio in the STM32WL3x is an updated version of the S2-LP with support for (G)MSK, DBPSK, and DSSS on top of the traditional 4-(G)FSK, 2-(G)FSK, OOK, and ASK. Consequently, the device natively supports 802.15.4g and is compatible with 6LoWPAN, MBus, Sigfox, WiSUN, and KNX protocols.

It is important to note that the chipset is compliant with all Sigfox RC Zones.

The STM32WL3x’s radio outperforms in both power power-efficiency and output power. In RX, it uses just 5.6 mA vs. 7 mA needed for the S2-LP. In transmitting mode (TX), it requires only 8 mA, while the S2-LP uses 10 mA. Additionally, it offers a greater output power at +20 dBm, surpassing the S2-LP at +16 dBm.




Equipped with the STM32 Cortex M0+ MCU, the STM32WL3x enables developers to implement the new Sigfox Open Source Stack available here: https://github.com/sigfox-tech-radio/sigfox-ep-lib. This integration offers multiple benefits, such as the option for asynchronous execution over the traditional blocking one. Additionally, enhancing the device efficiency, it allows for customisation in the number of frames per message and the desired data rates, either 100bps or 600bps, individually tailored for each message depending on the capabilities of the Regional RC network.

Last but not least, as the Sigfox Open Source stack is fully configurable and lightweight, developers can use the remaining memory to embed directly the application in the STM32WL3x.

This affordable chipset strikes an impressive balance between cost and performance, especially in power consumption. Its simplicity and frugality will be the key factors of its success.