Dev Kit Weekly: Silicon Labs Thunderboard BG22

June 19, 2020 Brandon Lewis

Hold up. Wait a minute. Didn’t we just do this kit on Dev Kit Weekly a couple weeks back?

No, actually. We looked at the Thunderboard Sense 2, which comes with a bunch of sensors and Bluetooth Low Energy support. This week’s kit, the Thunderboard BG22 doesn’t have quite as many sensors, but what it lacks there it makes up for by supporting the brand-spanking new Bluetooth 5.2 protocol.

The real big fish in 5.2 is low-energy “LE” audio, empowered by a feature called isochronous channels. It introduces the LC3 low-power, high-quality audio codec, and supports multiple synchronized audio streams so that audio data can be broadcast to more than one endpoint simultaneously, or so that devices like wireless earbuds and hearing aids can receive independently synchronized audio to both the left and right earbud.

At the heart of this Thunderboard is Si Labs’ EFR32BG22 secure SoC, which sports a 76.8 MHz Arm Cortex-M33 with DSP instructions and a floating-point unit neatly positioned alongside 512 kilobytes of flash, 32 kilobytes of RAM, and of course a Bluetooth 5.2 radio. The radio integrates support for the angle of arrival and angle of departure direction finding protocols that can be used in location-based applications, as well as an LE-coded PHY with forward error correction that tacks redundant bits onto packets being transmitted. While the LE-coded PHY necessarily reduces overall data rate, it also increases range significantly.

The EFR32BG22 is able to operate for more than 5 years, and potentially up to 10, on a CR2032. That’s because the SoC draws just 27 microamps per megahertz in active mode, 1.20 microamps in deep sleep.

Beyond the EFR32BG22, the Thunderboard BG22 also integrates its own power-saving features, such as separate power domains for the Si Labs humidity, temperature, UV, ambient light, and hall effect sensors and TDK InvenSense 6-axis IMU on the PCB. Each of these domains can be controlled individually to help save power by only utilizing the peripherals needed.

Another really nice touch that Si Labs includes with the Thunderboard family of development boards are ready-to-go iOS and Android apps that let you remotely manage and monitor the kits by toggling LEDs, detecting push-button presses, and viewing sensor data. But even better for you developers looking to get complete solutions to market quickly, the apps’ source code can be downloaded from Github to be used as a starting point.

So, if you’re ready to hop on the Bluetooth 5 train, you can learn more about the Thunderboard BG22 at There, you’ll be able to purchase one of your own for just $19.99.

But if you’re looking for a completely risk-free way to get your hands on one, simply enter this week’s raffle where we’ll be shipping off one of these kits to a lucky winner who fills out the form here:

Best of luck this week in the Silicon Labs BG22 raffle. And we’ll see you next week.

About the Author

Brandon Lewis

Brandon Lewis, Editor-in-Chief of Embedded Computing Design, is responsible for guiding the property's content strategy, editorial direction, and engineering community engagement, which includes IoT Design, Automotive Embedded Systems, the Power Page, Industrial AI & Machine Learning, and other publications. As an experienced technical journalist, editor, and reporter with an aptitude for identifying key technologies, products, and market trends in the embedded technology sector, he enjoys covering topics that range from development kits and tools to cyber security and technology business models. Brandon received a BA in English Literature from Arizona State University, where he graduated cum laude. He can be reached by email at

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