STM32L Series: Ultra-Low-Power 32-bit MCUs

STM32 and Ultra-Low Power

By choosing an STM32 microcontroller for your embedded application, you gain from STMicroelectronics' market-leading expertise in MCU architecture, technology, multi-source manufacturing, and long-term supply.

14 Product Series - More Than 50 Product Lines

The STM32 MCUs portfolio offers an extraordinary variety of options including Arm® Cortex®-M cores (M0, M0+, M3, M4, M33, and M7), giving developers flexibility to find the perfect match for their application. Compatibility of binaries, similar pinout assignments, proliferation of hardware IPs, and higher-level programming languages greatly facilitate the work of developers.

ST MCU Finder: Free mobile and desktop application to find the right STM32 MCU. Visit www.st.com/stmcufinder.

ST COMMUNITY: Ask, learn, share, discuss, become famous, and engage with the community of STM32 enthusiasts on community.st.com.

STM32 ULP Series

From cost-smart up to advanced performance, there is an STM32L series to match all your memory, analog, or peripheral needs.

STM32L: Ultra-Low-Power 32-bit MCU Series

ST's ultra-low-power MCU platform is based on a proprietary ultra-low-leakage technology. The STM32L0 (Arm® Cortex®-M0+), STM32L1 (Cortex-M3), STM32L4, STM32L4+ (Cortex-M4), STM32L5 (Cortex-M33), and STM8L (8-bit proprietary core) series represent a large range of microcontrollers for devices supplied from batteries or through energy harvesting, ensuring an optimized cost/performance ratio for low-power applications. With the industry's lowest current variation between -40 and +125°C, this platform offers outstandingly low current consumption at elevated temperatures. The MCUs reach the industry's lowest power consumption of 350 nA in Stop mode (with SRAM retention), while maintaining a wakeup time as low as 3.5 μs.

• The STM32L4 series offers ST's ultra-low-power platform with additional performance, providing 100 DMIPS with DSP instructions and a Floating-Point Unit (FPU), more memory (up to 1 Mbyte of Flash), and innovative features.
• The STM32L4+ series extends STM32L4 technology with higher performance (120 MHz/409 CoreMark from internal Flash), larger embedded memories (up to 2 Mbytes of Flash and 640 Kbytes of SRAM), and more advanced graphic features without compromising ultra-low power consumption.
• The STM32L5 series is designed for embedded applications requiring more security and lower power consumption, adding security with Arm® Cortex®-M33 and its TrustZone® and ST security implementation, leveraging best-in-class ultra-low power technology.

5 Product Series - 16 Product Lines: A Unique Offer

Key Series Features:

• STM32L5: 32-bit Arm® Cortex®-M33 + FPU at 110 MHz; 256 to 512 Kbytes Flash; Lowest power mode + RAM + RTC: 0.35 μA.
• STM32L4+: 32-bit Arm® Cortex®-M4 + FPU at 120 MHz; 1 to 2 Mbytes Flash; Lowest power mode + RAM + RTC: 1 μA.
• STM32L4: 32-bit Arm® Cortex®-M4 + FPU at 80 MHz; 64 Kbytes to 1 Mbyte Flash; Lowest power mode + RAM + RTC: 0.34 μA.
• STM32L1: 32-bit Arm® Cortex®-M3 at 32 MHz; 32 to 512 Kbytes Flash; Lowest power mode + RAM + RTC: 1.2 μA.
• STM32L0: 32-bit Arm® Cortex®-M0+ at 32 MHz; 8 to 192 Kbytes Flash; Lowest power mode + RAM + RTC: 0.67 μA.

Performance Metrics:

• ULPBench scores range from 75 to 447.
• CoreMark scores range from 93 to 427.

STM32 ULP MCUs: Applications

STM32 ULP MCUs are suitable for a wide range of applications:

• Power tools: Low current consumption (down to 450 nA in mode with RTC, 16 Kbytes SRAM), LP-UART, Pulse counter, 16-bit LP-Timer, 3.5 μs wakeup.
• Gas/water meters: 1.4 μA Stop mode with 128 Kbytes RAM+RTC, 4 μs wakeup, USB 2.0 OTG, 640 Kbytes SRAM, Arm® Cortex®-M4 with FPU (150 DMIPS).
• Electricity smart meters: Dynamic Efficiency 28 μA/MHz, FSMC for external memories, LCD control, TRNG and 256-bit AES for security, VBAT with RTC.
• Fitness/healthcare: Arm® Cortex®-M4 up to 120 MHz, 8 nA Shutdown mode, up to 2-Mbyte Flash, Dynamic Efficiency 28 μA/MHz, 12-/16-bit ADC.
• Sensor hub (Mobile phone/gaming): I2C FM+, Fast SPI, Fast ADC, FS USB host.
• Audio and voice recognition: Arm® Cortex®-M4 up to 120 MHz (31 μA/MHz at 100 DMIPS), Quad or Octo-SPI, digital filter for Sigma Delta, 12-bit ADC at 200 μA/MSPS, SAI/I2S.

STM32L0 Series

A tiny consumption budget for a wide application range.

STM32L0 Product Lines

The STM32L0 series features Arm® Cortex®-M0+ cores (32 MHz with MPU), offering features like dynamic voltage scaling, 5 clock sources, advanced RTC with calibration, 12-bit ADC, multiple USART, SPI, I2C, and 16-bit timers. Low-power peripherals are available in ultra-low-power modes.

STM32L0 Ultra-Low-Power Features:

• 33 DMIPS.
• Dynamic run mode down to 49 µA/MHz (with external DC/DC) and 76 µA/MHz (with LDO).
• Stop mode with RAM + LTC (low-power time clock): 420 nA.
• Fast Wakeup time: Stop to Run from Flash: 5 µs (3.5 µs from RAM); Standby to Run: 50 µs.
• Typical current: 166 µA/MHz (Dhrystone at 32 MHz).
• Power modes: Dynamic Run (28 µA), Low-power Run (10 µA), Low-power Sleep (5.5 µA), STOP with RTC (1.95 µA), Standby with RTC (1.95 µA).
• ULPBench score: 244 (CP), 95 (PP).
• CoreMark score: 75.

STM32L1 Series

A market-proven solution.

STM32L1 Product Lines

The STM32L1 series features Arm® Cortex®-M3 cores (32 MHz), offering ultra-low-power features, POR/PDR, 2 watchdogs, hardware CRC, internal RC, crystal oscillators, PLL, RTC calendar, 16- and 32-bit timers, 1x12-bit ADC, temperature sensor, and multiple-channel DMA.

STM32L1 Ultra-Low-Power Features:

• Arm® Cortex®-M3+ at 32 MHz, 33 DMIPS.
• Dynamic run mode: down to 177 µA/MHz.
• Stop with Full RAM retention: 435 nA (1.3 µA with RTC).
• Standby mode + RTC: 900 nA with backup registers.
• Standby mode: 280 nA with backup registers.
• Dual-bank Flash memory and True embedded EEPROM.
• Operates at up to 105 °C.
• ULPBench score: 155 (CP), 92.4 (PP).
• CoreMark score: 93.

STM32L4 Series

Successfully meet all challenges.

STM32L4 Product Lines

The STM32L4 series features Arm® Cortex®-M4 cores (DSP + FPU) at 80 MHz, offering features like ART Accelerator™, USART, SPI, I2C, Quad-SPI, 16- and 32-bit timers, SAI + audio PLL, SWP, 2x CAN, 2x 12-bit DACs, temperature sensor, low voltage operation (1.71V to 3.6V), VBAT mode, Unique ID, and capacitive touch sensing. Some devices include AES-128/256 and SHA-256 hardware acceleration.

STM32L4 Ultra-Low-Power Features:

• 100 DMIPS.
• Dynamic run mode at 28 µA/MHz.
• Down to 450 nA with 32 kHz RTC + 16 Kbytes of RAM + I/Os.
• Down to 200 nA with 32 kHz RTC or 8 nA without RTC.
• Operates at up to 125 °C.
• ULPBench score: 447 (CP), 167 (PP).
• CoreMark score: 273.

Power Consumption:

• Dynamic Run (Range 1, Up to 80 MHz): 31 µA/MHz.
• Dynamic Run (Range 2, Up to 26 MHz): 28 µA/MHz.
• Stop-2 mode: 720 nA / 950 nA.
• Standby mode: 200 nA / 450 nA.
• Shutdown mode: 8 nA / 200 nA.
• Wakeup to Run time: From Stop-2: 4 µs; From Standby: 14 µs; From Shutdown: 250 µs.

STM32L4 Online Training: Visit www.st.com/stm32l4-online-training.

STM32L4+ Series

Longer battery life and superior user experience.

STM32L4+ Product Lines

The STM32L4+ series features Arm® Cortex®-M4 cores (DSP + FPU) at 120 MHz, offering advanced features like ART Accelerator™, Chrom-ART Accelerator™, Chrom-GRC™ for round displays, USB OTG, SDIO, FSMC, MIPI-DSI, TFT Interface, CAN, Octo-SPI, 12-bit ADC, and 12-bit DACs. It also includes 128-/256-bit AES hardware encryption.

STM32L4+ Ultra-Low-Power Features:

• 233 ULPMark-CP score.
• 20 nA in shutdown mode.
• 2.5 µA in stop mode with full SRAM and peripheral states retention and with 4 µs wakeup time.
• Down to 43 µA/MHz in active mode.
• Superior graphic effects and fluid user interfaces.
• Zero wait state execution from internal Flash memory.
• CoreMark score: 409.

Power Consumption:

• Dynamic Run (Range 1, Up to 120 MHz): 55 µA/MHz.
• Dynamic Run (Range 2, Up to 26 MHz): 48 µA/MHz.
• Stop-2 mode: 500 nA / 800 nA.
• Standby mode: 125 nA / 480 nA.
• Shutdown mode: 33 nA / 300 nA.
• Wakeup to Run time: From Stop-2: 4 µs; From Standby: 14 µs; From Shutdown: 250 µs.

STM32L4+ Online Training: Visit www.st.com/stm32l4plus-online-training.

STM32L5 Series

Excellence in ultra-low-power with more security.

STM32L5 Product Lines

The STM32L5 series features Arm® Cortex®-M33 cores (TrustZone® + DSP + FPU) at 110 MHz, offering enhanced security and ultra-low-power capabilities. Features include ART Accelerator™, USART, SPI, I2C, Octo-SPI, 16/32-bit timers, SAI + audio PLL, SHA, TRNG, 2x Op-Amp, 2x Comp, 12-bit ADC, USB 2.0 Device, CAN-FD, and AES, PKA, OTFDEC (128/256-bit) for security. It also supports USB Type-C and Power Delivery.

STM32L5 Ultra-Low-Power Features:

• New Arm Cortex-M33 at 110 MHz performance (+20% vs Cortex-M4).
• New ST ART Accelerator™ with instruction cache.
• Embedded SMPS step-down converter (optional).
• Flexible hardware and software secure isolations with TrustZone®.
• 33 nA in shutdown mode.
• 3.6 µA in stop mode with full SRAM and peripheral states retention and 5 µs wake-up time.
• Down to 60 µA/MHz in active mode.
• 165 DMIPS.
• ULPBench score: 402 (CP), 56.5 (PP).
• CoreMark score: 427.

Power Consumption:

• Dynamic Run (Range 1, Up to 110 MHz): 60 µA/MHz.
• Dynamic Run (Range 2, Up to 26 MHz): 33 µA/MHz.
• Stop-2 mode: 200 nA / 450 nA.
• Standby mode: 125 nA / 430 nA.
• Shutdown mode: 33 nA / 250 nA.
• Wakeup to Run time: From Stop-2: 4 µs; From Standby: 14 µs; From Shutdown: 250 µs.

STM32L5 Video: Watch at https://youtu.be/Pa8gaHGDWYY.

STM32L Ecosystem

STM32 Hardware Tools

Various types of development boards enable you to get started with STM32L products:

• STM32 Nucleo boards: Affordable and flexible for trying new ideas and building prototypes with specialized expansion boards. They offer an open platform with an integrated debugger/programmer and wide connector choices (Arduino Uno Rev3, ST Zio, ST Morpho). Support for multiple IDEs and Arm® mbed™ tools.
• Discovery kits: Enable seamless exploration of key low-power features.
• Evaluation boards: Allow evaluation of all MCU functions and peripherals.

STM32 Nucleo Portfolio by Flash Memory Size:

Legend: STM32L0 series, STM32L1 series, STM32L4 series. Available with SMPS version (*QFN version).

STM32 Cellular-to-Cloud Discovery Packs

ST introduces two STM32 Cellular-to-Cloud Discovery Packs (P-L496G-CELL01 and P-L496G-CELL02) based on Quectel modems for 2G/3G and LTE Cat M1/NB1+2G networks, respectively. Each pack combines an STM32L496 Discovery board and an STMod+ Cellular add-on board. Software includes an embedded JavaScript engine and an X-CUBE-CLD-GEN STM32Cube expansion package. Packs include an ST eSIM with a complimentary trial plan.

STM32 Nucleo Expansion Boards

STM32 Nucleo development boards can be expanded using various add-on boards from ST and third parties. These boards implement specialized features for chosen applications and come with complementary STM32 software modules.

STM32L Wireless Connectivity Solutions: LoRaWAN™

ST offers affordable hardware tools for LoRa® solutions evaluation and development, combined with the LoRaWAN software expansion package for STM32Cube (I-CUBE-LRWAN). This includes the STM32 LoRa® Discovery kit (B-L072Z-LRWAN1), the STM32 expansion board (I-NUCLEO-LRWAN1), and the STM32 Nucleo pack (P-NUCLEO-LRWAN1).

STM32 Software Development Tools

ST proposes a 3-step approach for standard development in C:

1. Configure the microcontroller using the STM32CubeMX tool and optionally generate code.
2. Develop the application, compile, and debug using an IDE (e.g., IAR, Keil, AC6, Atollic, Coocox, Segger, Tasking).
3. Monitor the application non-intrusively with STMStudio.

STM32 Software Tools Ecosystem: Includes STM32CubeMX, STM32CubeProgrammer, ST-Link Utility, STM Studio, and various IDEs.

STM32 Power Shield: EEMBC-Approved Power-Monitoring Technology

The STM32 Power shield (X-NUCLEO-LPM01A) is an affordable tool for checking power consumption in embedded designs, especially for ultra-low-power devices like IoT endpoints. It supports voltage supply down to 1.8V, measures static current, dynamically monitors current from 100 nA to 50 mA, and computes EEMBC ULPMark scores. It works with the STM32CubeMonitor-Power graphical application for data visualization.

STM32 Embedded Software

ST's embedded software for STM32 microcontrollers offers various portability and optimization criteria:

• STM32Snippets: Highly optimized code examples using direct register access.
• Standard Peripheral Library: Ensures portability at the STM32 series level.
• STM32Cube embedded software: Ensures portability at the STM32 family level, facilitating application reuse.
• HAL (Hardware Abstraction Layer): Enables portability between different STM32 devices via standardized API calls.
• Low-layer (LL) APIs: Lightweight, optimized APIs for performance and runtime efficiency.
• CMSIS Driver and mbed abstraction layer: Microcontroller abstraction for Cortex-M based MCUs.
• Other solutions: STM32Java, .Net Micro framework, MATLAB/Simulink.

Specific Focus on STM32L Series: Use the STM32CubeMX Power Consumption Calculator wizard to determine power consumption and battery life by configuring chip settings, battery type, and application sequences.

Specific Offers for STM32L Series

User Recommendations

• STM32L1 users: For STM32L1-only requirements, the Standard Peripheral Library ensures good portability. STM32Cube is recommended for new designs (Order code: STSW-STM32077).
• STM32 portability needs: STM32Cube HAL is recommended for high portability requirements (Order codes: STM32CubeL0, STM32CubeL1, STM32CubeL4).
• STM32 optimization needs: STM32Cube LL APIs offer register-level control for minimized overhead and power optimization (Order codes: STM32CubeL0, STM32CubeL1, STM32CubeL4). For STM32L0 users prioritizing minimal software overhead and power optimization, STM32Snippets are suitable, but STM32Cube is recommended for new designs (Order code: STM32SnippetsL0).

For more information, visit www.st.com/stm32embeddedsoftware.