Yesterday, we wrote about the world’s smallest microcontroller (TI MSPM0C1104), which measures just 1.38mm2 in its smallest package. However, it is designed for general-purpose applications without built-in wireless connectivity. If you need Bluetooth LE in a tiny form factor, Silicon Labs BG29 wireless SoC, with a 2.8x 2.6mm package, is worth a look.
The BG29 features a Cortex-M33 core clocked at up to 76.8 MHz, up to 256KB SRAM, up to 1MB flash, various digital and analog peripherals, and security features that make it suitable for Bluetooth LE applications such as wearable health and medical devices, asset trackers, and battery-powered sensors.
Silicon Labs BG29 (EFR32BG29) specifications:
- CPU core – Arm Cortex-M33 @ 76.8 MHz with DSP instruction and floating-point unit
- Memory – Up to 256 kB RAM data memory
- Storage – Up to 1 MB flash program memory
- Wireless – 2.4 GHz radio
- Protocols – Bluetooth 5.4 Low Energy (LE) and Proprietary
- Modulation Formats
- 2 (G)FSK with fully configurable shaping
- OQPSK DSSS
- (G)MSK
- Rx Sensitivity
- -106.8 dBm @ 125 kbps GFSK
- -99 dBm @ 1 Mbit/s GFSK
- -96.1 dBm @ 2 Mbit/s GFSK
- Tx power up to +8 dBm
- Peripherals
- 2x UART/SPI/SmartCard (ISO 7816)/IrDA/I2S
- 2x Enhanced Universal Asynchronous Receiver/Transmitter (EUSART)
- 2x I2C with SMBus support
- Analog
- 16-bit Analog to Digital Converter (IADC)
- Analog Comparator (ACMP)
- Up to 26x General Purpose I/O pins with output state retention and asynchronous interrupts
- Audio – Digital microphone interface (PDM)
- 8-channel DMA Controller
- 12-channel Peripheral Reflex System (PRS)
- Timers
- 3x 16-bit Timer/Counter with 3 Compare/Capture/PWM channels
- 2x 32-bit Timer/Counter with 3 Compare/Capture/PWM channels
- 32-bit Real Time Counter
- 24-bit Low Energy Timer for waveform generation
- Watchdog Timer
- Precision Low-Frequency RC Oscillator to replace 32 kHz sleep crystal
- RFSENSE with selective OOK mode
- Die temperature sensor with +/- 1.5 °C accuracy after single-point calibration
- Coulomb counter integrated into DC-DC for accurate battery monitoring
- Security Features
- Hardware Cryptographic Acceleration for AES128/192/256, ChaCha20-Poly1305, SHA-1, SHA-2/256/384/512, ECDSA+ECDH(P-192, P-256, P-384, P-521), Ed25519 and Curve25519, J-PAKE, PBKDF2
- True Random Number Generator (TRNG)
- ARM TrustZone
- Secure Boot (Root of Trust Secure Loader)
- Secure Debug Unlock
- DPA Countermeasures
- Secure Key Management with PUF
- Anti-Tamper
- Secure Attestation
- Designed for PSA Level 3 support
- Supply Voltage
- With Buck DC-DC – 1.8 V to 3.8 V
- With Boost DC-DC – 1.2 V to 1.7 V
- System Energy Consumption
- 3.6 mA RX current (1 Mbps GFSK)
- 4 mA TX current @ 0 dBm output power
- 9 mA TX current @ 6 dBm output power
- 11 mA TX current @ 8 dBm output power
- 30 μA/MHz in Active Mode (EM0) at 76.8 MHz
- 3.4 μA EM2 DeepSleep current (256 kB RAM retention and RTC running from LFXO)
- 1.5 μA EM2 DeepSleep current (16 kB RAM retention and RTC running from LFXO)
- 0.16 μA EM4 current
- Packages
- QFN40 – 5 x 5 x 0.85 mm
- WLCSP45 – 2.8 x 2.8x 0.5 mm
- Temperature Range
- With Buck DC-DC – -40°C to 125°C (QFN40 only)
- With Boost DC-DC – -20°C to 55°C (QFN40 and WLCSP45)
There’s no information about software support, but we can assume the Simplicity Studio 5 IDE will be the tool of choice for firmware development. There’s no mention of development boards or evaluation kits either, but that’s probably because the announcement coincided with Embedded World, and Silicon Labs expects the BG29 family to become generally available in Q3 2025. Additional details may be found on the product page and the press release.
Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011.
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