ST Serves Up Two MCUs Peppered With Wireless and Low-Power Features
This week, STMicroelectronics introduced two new microcontroller (MCU) families for modern IoT applications: the STM32WBA6 and the STM32U3. As connected devices become the new norm, designers have been facing challenges with balancing high performance, reliable connectivity, and energy efficiency in connected devices. ST believes its new MCUs will make these trade-offs more manageable for future IoT deployments.
The STM32WBA6 and the STM32U3.
STM32WBA6: A Wireless MCU for Performance and Efficiency
The new STM32WBA6xxx series (datasheet linked) incorporates a high-performance Arm Cortex-M33 32-bit RISC core operating at frequencies up to 100 MHz. The core includes a single-precision floating-point unit (FPU) that supports all Arm single-precision data-processing instructions and data types. It also includes high-speed memory options, with up to 2 Mbytes of Flash and 512 Kbytes of SRAM, alongside a broad range of enhanced I/Os and peripherals.
For connectivity, the STM32WBA6 MCU uses a 2.4-GHz radio that supports Bluetooth LE, Matter, Thread, and Zigbee. Notably, the devices support a concurrent operation mode that lets the device run multiple protocols simultaneously. The radio offers solid performance, with sensitivity reaching -100 dBm across the specified range.
The 2.4-GHz radio block diagram.
By combining the processing core, peripherals, and wireless subsystem into a single unit, STM32WBA6 MCUs aim to simplify design, reduce assembly size, and lower component costs.
STM32U3: An MCU for Low-Power, Remote Applications
STMicroelectronics’ STM32U3 MCUs (datasheet linked) feature advanced power-saving technology for smart connected devices in remote settings, such as those powered by coin cells. To this end, the STM32U385xx series is built on a high-performance Arm Cortex-M33 32-bit RISC core that runs up to 96 MHz and includes a single-precision FPU supporting all Arm data-processing instructions, a full digital signal processing (DSP) instruction set, and a memory protection unit for enhanced security.
The STM32U3 series is also the first STM32 family to use near-threshold voltage technology, which dramatically extends battery life. The near-threshold technology operates transistors below the conventional power supply levels (1.20 V to 0.9 V). Core logic functions operate at voltages as low as 0.65 V. With this tech, the STM32U3 family devices achieve active consumption as low as 10 µA/MHz and "industry-leading efficiency" of 117 Coremark/mW with a static mode under 2 µA.
STM32U375/385 block diagram.
For security, secret keys are permanently stored in secure memory to eliminate vulnerable CPU fetches, while each device is factory-provisioned with attestation credentials for enhanced security and streamlined setup. Combined with SESIP3 and PSA Level3-certified features, these security measures help ensure compliance with forthcoming RED and CRA regulations.
Powerful Additions for IoT Deployments
The new MCUs from STMicroelectronics add to the increasing marketplace of integrated, energy-efficient systems. With enhanced security, reliable connectivity, and reduced power consumption, ST believes that these solutions could have major implications for the next wave of IoT deployments.
