For battery-operated IoT products:
Power Bluetooth 5.2 applications for 10 years with a button cell


You can use the Blue Gecko 22 SoC from SILICON LABS to operate battery-operated IoT applications for up to 10 years with a button cell.

The energy-saving ARM® Cortex® M33 core offers outstanding energy efficiency of 27 µA/MHz (active mode) and 1.2 µA in the power saving mode.

The target applications include Bluetooth network nodes with low power consumption, intelligent door locks, lifestyle gadgets and fitness equipment. Asset tracking tags, beacons and indoor navigation are another application area for the energy-saving Geckos.

Position determination with Bluetooth

A new type of position determination in the room was defined with Bluetooth 5.1.

In contrast to the relatively rough determination of the distance via the received signal strength, the direction of the radio signal is now determined.

There are two different methods in this respect:


AoA – Angle of Arrival

The receiver has several antennas for this process. When the signal of a beacon is received, the angle of incidence of the signal can be determined from the different travel times and phase position of the various antennas.

AoD – Angle of Departure

This method functions more or less in reverse. A beacon transmits its signal via several antennas.
The receiver can then determine the angle at which the received signal was emitted from the transmitter based on the phase positions of the various partial signals.

Both processes can be used to determine the position of a mobile device in the room with several known reference points and the respective signal angles.

Extensive security functions

Security is a key issue for networked applications. SILICON LABS has therefore improved the security function for the Wireless Gecko series 2 and considerably extended it. The following are implemented and executed in the hardware and software:


  • Hardware-accelerated crypto unit
    Faster, more energy efficient and better security as a pure software solution
  • True Random Number Generator (TRNG)
    Conforms to NIST SP800-90 and AIS-31
    Authentication of firmware updates
    Prevents the loading of manipulated firmware or a rollback to old versions
  • Secure Debug with Lock/Unlock
    Debug locked for standard devices
    Authenticated access for extended error analysis
  • TrustZone
    Cost-optimised hardware separation of security-related data

The Key Features at a glance:

Bluetooth 5.2

Dynamic transmission power

Position determination with AoA and AoD
Transmission power + 6dBm 


27 µA/MHz active

1.4 µA EM2 Sleep Mode with 32 KB RAM

0.5 µA EM4 Deep Sleep with RTC

ARM® Cortex® M33 with TrustZone

76.8 MHz

Up to 512 KB Flash and 32 KB RAM housing: QFN32 (4 x 4 mm), QFN40
(5 x 5 mm) 

Extended security functions

Hardware-accelerated cryptography

Root of Trust and Secure Loader

Starter kits for easy entry into the BLE world of SILICON LABS:


  • 1x Wireless starter kit main board
  • 1x SLWRB4182A +6 dBm QFN40 radio board
  • 1x SLWRB4183A +6 dBm QFN32 radio board


Hardware in the form of SoC or modules, as well as the appropriate software stacks and tools.
You obtain everything from a single source at SILICON LABS.

Simplicity Studio 4 is the focal point for your development. Based on the Eclipse environment, all the information and tools are available here with just a few clicks.

You will receive expert compiler support from GCC and IAR.

We would be happy to provide you with more information on request.


+49 6126 590-255
+49 6126 590-133

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