Silicon Labs Spins Bluetooth SoC and MCU for Small Form-factor Designs

March 17, 2023 by Jeff Child

With a goal of serving the design needs of small form-factor embedded systems, Silicon Labs is rolling out families of MCUs and wireless SoCs in tiny packages.

We wrap up our week at Embedded World today, this time with a pair of ICs from Silicon Labs. Earlier this week at the event, the company announced its xG27 family of Bluetooth systems on chips (SoCs) and the BB50 microcontroller (MCU).

The company is targeting these ICs at the smallest form factor IoT devices. According to Silicon Labs, the xG27 and BB50 families range in size from 2 mm2 to 5 mm2. That translates to smaller than the width of a No. 2 pencil lead.


At Silicon Labs’ Embedded World booth, All About Circuits Editor-in-Chief Jeff Child gets a Bluetooth distance detection demo from Verthika Varati, Applications Engineer at Silicon Labs. As Jeff—holding the Bluetooth module in his hand—steps back from the demo stand, a display accurately updates his distance away.


With these sizes, the devices are well suited for tiny, battery-optimized device designs. Examples include connected medical devices, wearables, asset monitoring tags, smart sensors, simple consumer electronics like toothbrushes and toys, and more. 

In this article, we delve into the key specifications and features offered by these new devices.


xG27 SoC Enables Bluetooth in Tiny Designs

The xG27 family of SoCs comprises two ICs: the BG27, for Bluetooth connectivity, and the MG27, supporting Zigbee and other proprietary protocols. Both devices embed an Arm Cortex M33 CPU. The BG27 and MG27 also share a number of oher common features.

The two ICs are available in wafer-level Chip Scale Packaging (CSP) as small as 2.3 mm x 2.6 mm. This makes them well suited for small and unobtrusive device design, such as medical patches, continuous glucose monitors, wearable electrocardiograms, and asset tracking tags. The two wireless SoCs also feature an integrated DC-DC boost converter. This enables the ICs to run off batteries as low as 0.8 V.


Block diagram of the BG27 SoC supporting Bluetooth 5.3 connectivity. (Click image to enlarge)

Block diagram of the BG27 SoC supporting Bluetooth 5.3 connectivity. (Click image to enlarge)


The BG27 and MG27 also each embed an integrated Coulomb counter. This allows battery level monitoring to avoid battery depletion. For security, the chips feature Silicon Labs’ Secure Vault with Virtual Security Engine (VSE). These provide secure boot and debug hardened against glitch attacks and tamper protection. They also provide capabilities designed to protect the device and its users’ data from local and remote cyber threats.

A Shelf Mode implemented on both chips shrinks energy use to less than 20 nA. This mode lets devices be transported and stocked on shelves while maintaining nearly full battery life.


8-bit MCUs for Simple IoT Edge Design Ins

Wireless connectivity is a central part of IoT. But not all IoT devices need to be connected, says Silicon Labs. An example is in commercial lighting. The application may just need a simple control mechanism for the light based on ambient light or occupancy sensors.

Another example: in the consumer goods space, a toothbrush may have connectivity into their brushes to provide users with friendly reminders and insights about their brushing patterns. However, manufacturers still need to serve consumers who prefer non-connected versions of the devices.

The tiny BB50 MCUs are available in packaging options ranging from 2 mm2 to 5 mm2.

The tiny BB50 MCUs are available in packaging options ranging from 2 mm2 to 5 mm2. (Click image to enlarge)


It’s with all this in mind that Silicon Labs says it’s offering its new 8-bit BB50 MCUs. The devices use common tools and software for 8-bit and 32-bit, like Silicon Labs Simplicity Studio and a fully-featured 8-bit compiler. 

The BB50 MCUs feature a high-performance 8-bit 8051-based core optimized for a large number of single-cycle instructions to improve operating efficiency. Wide operating voltages and low-power modes are provided for battery applications to improve energy efficiency for a large variety of battery sizes.

As mentioned earlier, the BB50 MCUs are available in various packaging options ranging from 2 mm2  to 5 mm2 to optimize for size needs. Silicon Labs has hundreds of firmware examples to allow engineers to easily add functionality to an existing product with little or no additional firmware development chores.


All images used courtesy of Silicon Labs