Highly Integrated STMicroelectronics STM32WL SiP Module Simplifies LoRaWAN Device Development

STMicroelectronics introduced a new device to its STM32WL series of wireless systems on chips. The new LoRaWAN sub-1 GHz STM32WL5MOC system in package (SiP) combines a dual-core STM32 microcontroller, RF radio, switch mode power supply, and passive components into a single LGA package. This module significantly reduces bill of material costs, board space, and design time for LoRaWAN-based IoT devices.

The STM32WL5MOC SiP is a 10x10 milliliter LGA92 package that significantly simplifies RF design by integrating nearly every component needed from the processor core to the antenna, including power and the passives. Thanks to these clever integrations reducing external component count, you can use it with a two-layer PCB design!

The CPU core is the STM32WL55JC SoC. This existing SoC combined a general-purpose STM32 microcontroller (MCU) with a sub-1 GHz radio. The MCU has an Arm Cortex-M4 with DSP extensions, Arm Cortex-M0+, 64 KB RAM, 256 KB Flash, memory protection, and security features. There is optional support for a STSAFE-A110 module. These I2C-based modules add authentication and secure data management to a local (or remote) host microcontroller.

The radio operates license-free worldwide using the 864 to 928 MHz band. The RF output power level is selectable for different regions. A 22 dBm level supports the US and Asian countries. And a 15 dBm level is suitable for European regions. It is pre-certified for LoRaWAN and Sigfox networks. It also supports modulation schemes like (G)FSK, (G)MSK, BPKS, wM-Bus, Mioty, and others.

By integrating so many components into the new SiP, STMicro has made designing a LoRaWAN (or other sub-1 GHz) IoT device significantly easier. For example, the SiP contains an embedded switch-mode power supply (SMPS) with filtering capacitors! Additionally, it has a low-speed 32 kHz and a high-speed 32 MHz temperature-compensated crystal oscillator (TCXO). Finally, it includes an integrated passive device (IPD) for matching the RF path.

A development board for the STM32WL5MOC SiP is also available. The B-WL5M-SUBG1 is a wireless prototyping board with an SMA antenna port and several STMicroelectronics sensors. Sensors include temperature, 3-axis magnetometer, 3-D accelerometer, 3-D gyroscope, and piezoresistive absolute pressure sensors. The board also has a 20-pin STMod+ interface that allows adding small-form-factor daughterboards.

Since the microcontroller core already exists, significant software support is available for the new SiP. You can use the STM32Cube MCU package called STM32CubeWL. This package contains the low-level APIs, a hardware abstraction layer (HAL), RTOS, and software stacks for LoRaWAN and Sigfox. Alternatively, third-party IDEs like IAR Embedded Workbench support the MCU as well.

Both the chip and development board are available now from STMicro's web store or electronic component distributors. You can find more information about them, pricing, and their datasheets on the STM32WL5MOC or B-WL5M-SUBG1 product pages.