Ultra-low-power with FPU ARM Cortex-M4 MCU 80 MHz with 256 Kbytes Flash

The STM32L431xx devices are the ultra-low-power microcontrollers based on the high-performance ARM® Cortex®-M4 32-bit RISC core operating at a frequency of up to 80 MHz. The Cortex-M4 core features a Floating point unit (FPU) single precision which supports all ARM single-precision data-processing instructions and data types. It also implements a full set of DSP instructions and a memory protection unit (MPU) which enhances application security.

The STM32L431xx devices embed high-speed memories (Flash memory up to 256 Kbyte, 64 Kbyte of SRAM), a Quad SPI flash memories interface (available on all packages) and an extensive range of enhanced I/Os and peripherals connected to two APB buses, two AHB buses and a 32-bit multi-AHB bus matrix.

The STM32L431xx devices embed several protection mechanisms for embedded Flash memory and SRAM: readout protection, write protection, proprietary code readout protection and Firewall.

The devices offer a fast 12-bit ADC (5 Msps), two comparators, one operational amplifier, two DAC channels, an internal voltage reference buffer, a low-power RTC, one general-purpose 32-bit timer, one 16-bit PWM timer dedicated to motor control, four general-purpose 16-bit timers, and two 16-bit low-power timers.

In addition, up to 21 capacitive sensing channels are available.

They also feature standard and advanced communication interfaces.

The STM32L431xx operates in the -40 to +85 °C (+105 °C junction), -40 to +105 °C (+125 °C junction) and -40 to +125 °C (+130 °C junction) temperature ranges from a 1.71 to 3.6 V power supply. A comprehensive set of power-saving modes allows the design of low-power applications.

Some independent power supplies are supported: analog independent supply input for ADC, DAC, OPAMP and comparators. A VBAT input allows to backup the RTC and backup registers.

The STM32L431xx family offers nine packages from 32 to 100-pin packages.

Key Features

  • Ultra-low-power with FlexPowerControl
    • 1.71 V to 3.6 V power supply
    • -40 °C to 85/105/125 °C temperature range
    • 200 nA in VBAT mode: supply for RTC and 32x32-bit backup registers
    • 8 nA Shutdown mode (5 wakeup pins)
    • 28 nA Standby mode (5 wakeup pins)
    • 280 nA Standby mode with RTC
    • 1.0 μA Stop 2 mode, 1.28 μA with RTC
    • 84 μA/MHz run mode
    • Batch acquisition mode (BAM)
    • 4 μs wakeup from Stop mode
    • Brown out reset (BOR)
    • Interconnect matrix
  • Core: ARM® 32-bit Cortex®-M4 CPU with FPU, Adaptive real-time accelerator (ART Accelerator™) allowing 0-wait-state execution from Flash memory, frequency up to 80 MHz, MPU, 100DMIPS and DSP instructions
  • Performance benchmark
    • 1.25 DMIPS/MHz (Drystone 2.1)
    • 273.55 CoreMark® (3.42 CoreMark/MHz @ 80 MHz)
  • Energy benchmark
    • 176.7 ULPBench® score
  • Clock Sources
    • 4 to 48 MHz crystal oscillator
    • 32 kHz crystal oscillator for RTC (LSE)
    • Internal 16 MHz factory-trimmed RC (±1%)
    • Internal low-power 32 kHz RC (±5%)
    • Internal multispeed 100 kHz to 48 MHz oscillator, auto-trimmed by LSE (better than ±0.25 % accuracy)
    • Internal 48 MHz with clock recovery
    • 2 PLLs for system clock, audio, ADC
  • Up to 83 fast I/Os, most 5 V-tolerant
  • RTC with HW calendar, alarms and calibration
  • Up to 21 capacitive sensing channels: support touchkey, linear and rotary touch sensors
  • 11x timers: 1x 16-bit advanced motor-control, 1x 32-bit and 2x 16-bit general purpose, 2x 16-bit basic, 2x low-power 16-bit timers (available in Stop mode), 2x watchdogs, SysTick timer
  • Memories
    • Up to 256 KB single bank Flash, proprietary code readout protection
    • 64 KB of SRAM including 16 KB with hardware parity check
    • Quad SPI memory interface
  • Rich analog peripherals (independent supply)
    • 1× 12-bit ADC 5 Msps, up to 16-bit with hardware oversampling, 200 μA/Msps
    • 2x 12-bit DAC, low-power sample and hold
    • 1x operational amplifier with built-in PGA
    • 2x ultra-low-power comparators
  • 16x communication interfaces
    • 1x SAI (serial audio interface)
    • 3x I2C FM+(1 Mbit/s), SMBus/PMBus
    • 4x USARTs (ISO 7816, LIN, IrDA, modem)
    • 1x LPUART (Stop 2 wake-up)
    • 3x SPIs (4x SPIs with the Quad SPI)
    • CAN (2.0B Active) and SDMMC interface
    • SWPMI single wire protocol master I/F
    • IRTIM (Infrared interface)
  • 14-channel DMA controller
  • True random number generator
  • CRC calculation unit, 96-bit unique ID
  • Development support: serial wire debug (SWD), JTAG, Embedded Trace Macrocell™

Circuit Diagram



Technical Documentation

Product Specifications
Description Version Size
DS11453 DS11453: Ultra-low-power ARM® Cortex®-M4 32-bit MCU+FPU, 100DMIPS, up to 256KB Flash, 64KB SRAM, analog, audio 2.0 2 MB
Application Notes
Description Version Size
AN4629 AN4629: ADC hardware oversampling for microcontrollers of the STM32 L0 and L4 series 1.0 321 KB
AN5012 AN5012: Analog-to-digital audio conversion example using STM32L4 Series microcontroller peripherals 1.0 1 MB
AN3126 AN3126: Audio and waveform generation using the DAC in STM32 microcontrollers 3.0 816 KB
AN4775 AN4775: Basics and low-cost solution proposals to move from legacy USB2.0 connector to USB Type-C™ connector with STM32 devices 1.0 443 KB
AN3154 AN3154: CAN protocol used in the STM32 bootloader 6.0 630 KB
AN4894 AN4894: EEPROM emulation techniques and software for STM32L4 Series microcontrollers 1.0 461 KB
AN1709 AN1709: EMC design guide for ST microcontrollers 2.0 843 KB
AN3960 AN3960: ESD considerations for touch sensing applications on MCUs 2.0 353 KB
AN1181 AN1181: Electrostatic discharge sensitivity measurement 1.6 49 KB
AN4566 AN4566: Extending the DAC performance of STM32 microcontrollers 2.0 365 KB
AN4776 AN4776: General-purpose timer cookbook 2.0 1 MB
AN4555 AN4555: Getting started with STM32L4 Series hardware development 4.0 727 KB
AN4312 AN4312: Guidelines for designing touch sensing applications with surface sensors 3.0 1 MB
AN4299 AN4299: Guidelines to improve conducted noise robustness on STM32F0/F3, STM32L0/L4 series touch sensing applications 3.0 613 KB
AN3236 AN3236: Guidelines to increase the number of touch sensing touchkeys 4.0 300 KB
AN4750 AN4750: Handling of soft errors in STM32 applications 2.1 410 KB
AN4803 AN4803: High-speed SI simulations using IBIS and board-level simulations using HyperLynx SI on STM32 32-bit ARM® Cortex® MCUs 1.1 2 MB
AN2834 AN2834: How to get the best ADC accuracy in STM32 microcontrollers 3.1 1 MB
AN4229 AN4229: How to implement a vocoder solution using STM32 microcontrollers 1.1 466 KB
AN4991 AN4991: How to wake up an STM32F0/F3/L0/L4 microcontroller from low-power mode with the USART or the LPUART 1.0 317 KB
AN4221 AN4221: I2C protocol used in the STM32 bootloader 5.0 682 KB
AN4777 AN4777: Implications of memory interface configurations on low-power STM32 microcontrollers 2.0 435 KB
AN4838 AN4838: Managing memory protection unit (MPU) in STM32 MCUs 1.0 284 KB
AN4809 AN4809: Migrating between STM32L0 Series and STM32L4 Series microcontrollers 2.0 786 KB
AN4649 AN4649: Migrating from STM32F1 Series to STM32L4 Series microcontrollers 4.0 1 MB
AN4831 AN4831: Migrating from STM32F2x5 line to STM32L4 Series microcontrollers 2.0 870 KB
AN4832 AN4832: Migrating from STM32F303 line to STM32L4 Series microcontrollers 2.0 761 KB
AN4616 AN4616: Migrating from STM32F401 and STM32F411 lines to STM32L4 Series microcontrollers 4.0 1 MB
AN4821 AN4821: Migrating from STM32F405/415 line and STM32F407/417 line to STM32L4 Series microcontrollers 2.0 1 MB
AN4612 AN4612: Migrating from STM32L1 Series to STM32L4 Series microcontrollers 4.0 1 MB
AN4635 AN4635: Minimization of power consumption using LPUART in microcontrollers of the STM32L0 and STM32L4 series 3.2 1 MB
AN4746 AN4746: Optimizing power and performance with STM32L4 Series microcontrollers 2.0 725 KB
AN2867 AN2867: Oscillator design guide for STM8AF/AL/S and STM32 microcontrollers 11.0 2 MB
AN4758 AN4758: Proprietary code read-out protection on microcontrollers of the STM32L4 series 1.2 1017 KB
AN4760 AN4760: Quad-SPI (QSPI) interface on STM32 microcontrollers 1.0 2 MB
AN4286 AN4286: SPI protocol used in the STM32 bootloader 4.0 551 KB
AN4908 AN4908: STM32 USART automatic baud rate detection 1.0 268 KB
AN4013 AN4013: STM32 cross-series timer overview 6.0 555 KB
AN4989 AN4989: STM32 microcontroller debug toolbox 2.0 5 MB
AN2606 AN2606: STM32 microcontroller system memory boot mode 31.0 3 MB
AN4230 AN4230: STM32 microcontrollers random number generation validation using NIST statistical test suite 2.0 517 KB
AN5044 AN5044: STM32 standard peripheral library to STM32Cube low-layer migration 1.0 1 MB
AN4726 AN4726: STM32Cube firmware examples for STM32L4 Series 8.0 498 KB
AN4729 AN4729: STM32L0/L4 FIREWALL overview 1.2 114 KB
AN4621 AN4621: STM32L4 ultra-low-power features overview 3.0 458 KB
AN4310 AN4310: Sampling capacitor selection guide for MCU based touch sensing applications 3.0 208 KB
AN4316 AN4316: Tuning a STMTouch-based application 3.0 783 KB
AN3155 AN3155: USART protocol used in the STM32 bootloader 7.0 617 KB
AN3156 AN3156: USB DFU protocol used in the STM32 bootloader 6.0 373 KB
AN4277 AN4277: Using STM32 device PWM shut-down features for motor control and digital power conversion 4.0 834 KB
AN4995 AN4995: Using an electromyogram technique to detect muscle activity 1.0 634 KB
AN4759 AN4759: Using the hardware real-time clock (RTC) in low-power modes with STM32 microcontrollers 3.0 1 MB
AN4655 AN4655: Virtually increasing the number of serial communication peripherals in STM32 applications 1.1 338 KB
Technical Notes & Articles
Description Version Size
TN1163 TN1163: Description of WLCSP for microcontrollers and recommendations for its use 4.0 1 MB
TN0830 TN0830: How to use EWARM 6.2x with projects built with EWARM 6.1 and previous versions 1.2 97 KB
TN1204 TN1204: Tape and reel shipping media for STM32 microcontrollers in BGA packages 2.1 745 KB
TN1205 TN1205: Tape and reel shipping media for STM8 and STM32 microcontrollers in FPN packages 3.0 753 KB
TN1206 TN1206: Tape and reel shipping media for STM8 and STM32 microcontrollers in QFP packages 3.0 830 KB
TN1207 TN1207: Tape and reel shipping media for STM8 and STM32 microcontrollers in SO packages 1.0 755 KB
TN1208 TN1208: Tape and reel shipping media for STM8 and STM32 microcontrollers in TSSOP and SSOP packages 1.0 743 KB
Reference Manuals
Description Version Size
RM0394 RM0394: STM32L43xxx STM32L44xxx STM32L45xxx STM32L46xxx advanced ARM®-based 32-bit MCUs 3.0 16 MB
Programming Manuals
Description Version Size
PM0214 PM0214: STM32F3, STM32F4 and STM32L4 Series Cortex®-M4 programming manual 5.0 3 MB
Errata Sheets
Description Version Size
ES0320 ES0320: STM32L431xx device limitations 3.0 371 KB

HW Model, CAD Libraries & SVD

HW Model, CAD Libraries & SVD
Description Version Size
STM32L4 Boundary Scan Description Language (BSDL) files 3.1 186 KB
STM32L4 CAD Symbol and Footprint files 1.3 2 MB
STM32L4 IBIS models 2.3 23 MB
STM32L4 System View Description 1.1 424 KB

Presentations & Training Material

Description Version Size
STM32L4 MCU series - Excellence in ultra-low-power with performance 4.0 1 MB

Publications and Collaterals

Description Version Size
Get ready for the largest IoT development ecosystem 17.02 741 KB
STM32 GUI solutions - Advanced HMI now achievable on embedded systems 1.0 1 MB
STM32 Nucleo boards 17.07 1 MB
STM32 for makers Releasing your creativity 16.2 2 MB
STM32L4 Series - Ultra-low-power and performance 17.07 770 KB
Description Version Size
STM32™ 32-bit MCU family - Leading supplier of ARM® Cortex®-M microcontrollers 18.0 1 MB
STM32L series - Ultra-low-power 32-bit MCUs 16.4 3 MB
Magazine Articles
Description Version Size
Design & Elektronik magazine - Benchmark ULPBench debunked 1.1 12 MB

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Part Number Package Packing Type Operating Temperature (°C) (min) Operating Temperature (°C) (max) Marketing Status Unit Price (US$) * Quantity ECCN (EU) ECCN (US) Country of Origin More info Order from ST Order from Distributors
STM32L431KCU6 UFQFPN 32 5x5x0.55 Tray -40 85 Active 2.228 10000 NEC 3A991A2 CHINA MORE INFO

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Part Number Marketing Status Package Grade RoHS Compliance Grade Material Declaration**
STM32L431KCU6 ActiveUFQFPN 32 5x5x0.55IndustrialEcopack2 0 0

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