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STMicroelectronics STM32L031K4U6
- Part No.:
- STM32L031K4U6
- Manufacturer:
- STMicroelectronics
- Category:
- Microcontrollers
- Package:
- 32-UFQFN Exposed Pad
- Datasheet:
-
STM32L031K4U6.pdf
- Description:
- IC MCU 32BIT 16KB FLASH 32UFQFPN
- Quantity:
- Payment:
- Shipping:
Inventory:3,529
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Product details
Overview
STM32L031K4U6 from STMicroelectronics is an ultra-low-power 32-bit Arm® Cortex®-M0+ microcontroller in UFQFPN28 (4×4 mm) package, featuring 16 KB Flash, 8 KB SRAM, 1 KB EEPROM with ECC, 12-bit ADC (1.14 Msps), and dual ultra-low-power comparators. It operates from 1.65–3.6 V across –40 to +125 °C and delivers 76 µA/MHz in Run mode - ideal for battery-powered sensor nodes and smart metering endpoints.
For engineers reviewing the STM32L031K4U6 datasheet, STM32L031K4U6 pinout, STM32L031K4U6 application, or STM32L031K4U6 equivalent, key selection criteria include standby current (0.23 µA), RTC-enabled Stop mode (0.6 µA with 8 KB RAM retention), 5 µs Flash wakeup time, and 31 I/Os with 5V tolerance - critical for energy-constrained industrial and IoT edge devices.
Technical Context
The STM32L031K4U6 integrates a Cortex-M0+ core running up to 32 MHz with dynamic voltage scaling, supported by multiple clock sources: 16 MHz factory-trimmed HSI (±1%), 32 kHz LSE for RTC calibration, and PLL for CPU clock generation. Its low-power architecture includes five operational modes - Run, Sleep, Low-power Run, Stop, and Standby - each with distinct peripheral enablement and retention policies.
Peripheral interconnect is managed via an AHB/APB matrix supporting concurrent DMA transfers to ADC, USART, SPI, I²C, and timers. The device embeds a 96-bit unique ID, CRC calculation unit, and serial wire debug (SW-DP), enabling secure firmware updates and real-time trace in resource-constrained deployments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Core | Arm Cortex-M0+, 32 MHz max - enables deterministic real-time control with <1-cycle branch penalty and Thumb-2 instruction set. |
| Memory | 16 KB Flash (ECC), 8 KB SRAM, 1 KB EEPROM (ECC) - supports robust firmware storage, data logging, and parameter retention without external components. |
| Power Consumption | 0.23 µA Standby (2 wakeup pins), 0.6 µA Stop + RTC + 8 KB RAM - extends coin-cell battery life to >10 years in periodic-sensing applications. |
| ADC | 12-bit, 1.14 Msps, 10-channel, down to 1.65 V supply - allows high-resolution analog sensing directly from low-voltage sensors without signal conditioning. |
| Timers | 8x timers including 1x 16-bit with 4 channels, 1x ultra-low-power LPTIM, RTC, SysTick, and 2x watchdogs - supports precise timing, pulse generation, and fail-safe monitoring. |
| I/O | 31 GPIOs (5V tolerant), 38 fast I/Os total - simplifies interface to legacy 5V peripherals and reduces level-shifter count in mixed-voltage systems. |
| Clock Sources | HSI16 (±1%), LSE (32 kHz), MSI (65 kHz–4.2 MHz), PLL - eliminates need for external crystals in cost-sensitive designs while maintaining RTC accuracy. |
Pinout & Package
STM32L031K4U6 uses the UFQFPN28 (4 × 4 mm, 0.5 mm pitch) package, compliant with ECOPACK®2 environmental standards. Pin assignments are validated per STMicroelectronics DS10668 Rev 6, Section 4 ("Pin descriptions") and Table 15 ("Pin definitions").
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VDD | Main power supply (1.65–3.6 V) | Primary core and I/O rail; decoupling required per datasheet layout guidelines to maintain low-noise operation in ultra-low-power modes. |
| VSS | Ground reference | Dedicated analog/digital ground plane connection point; separation from noisy digital return paths improves ADC SNR. |
| NRST | Active-low reset input | Asynchronous reset with internal pull-up; accepts 5V-tolerant logic levels and supports external reset button or supervisor IC integration. |
| PA0–PA15 | General-purpose I/Os | 31 total GPIOs (PA0–PA15, PB0–PB12, PC13–PC15); 5V-tolerant on most pins - enables direct interfacing with 5V sensors, displays, and logic without level shifters. |
| PA1 | ADC_IN1 / TIM2_CH2 | Shared analog input and timer capture channel - supports simultaneous voltage monitoring and event timing in predictive maintenance firmware. |
| PA2/PA3 | USART2_TX/USART2_RX | Dedicated full-duplex UART interface - used for AT-command-based BLE/Wi-Fi module communication or field diagnostics via RS-232 transceiver. |
| PA4/PA5 | SPI1_NSS/SPI1_SCK | Hardware SPI master clock and chip select - drives external flash memory or pressure/temperature sensors with deterministic timing and minimal CPU overhead. |
| PC13 | LSE_OSC_IN / RTC_WKUP | Low-speed crystal input and wake-up source - enables calendar-based scheduling and sub-second interrupt generation during Stop mode with <0.6 µA draw. |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low-power BOR | 5 selectable brownout thresholds (1.65–2.9 V) - ensures reliable reset behavior across wide battery discharge curves without external supervisors. |
| Programmable voltage detector (PVD) | Configurable trip points monitor VDD in real time - triggers interrupt or reset before critical undervoltage causes memory corruption or analog inaccuracies. |
| Pre-programmed bootloader | Supports USART and SPI firmware updates - enables field reprogramming without JTAG/SWD hardware, reducing service cost and downtime. |
| Embedded ECC | On-chip error correction for Flash and EEPROM - prevents silent data corruption in long-life deployments (e.g., utility meters operating >15 years). |
| Temperature sensor | Calibrated ±1.5 °C accuracy (–40 to 85 °C) - provides system thermal monitoring without external ICs, supporting fan control or battery thermal cutoff logic. |
Applications
| Smart Utility Metering | Wireless Sensor Node |
|---|---|
Use Scenario: Battery-powered gas/water meter with hourly pressure/flow sampling and LoRaWAN transmission every 12 hours. IC Role / Device Role / Timing Role: Primary MCU executing sensor acquisition, data compression, RTC-triggered transmission, and ultra-low-power sleep management. Use Value: 0.23 µA Standby current and 5 µs wakeup enable >15-year battery life using CR2450 cells while maintaining precise timestamping via integrated RTC. | Use Scenario: Industrial vibration sensor node mounted on motor housing, sampling accelerometer data at 1 kHz and transmitting anomalies via BLE. IC Role / Device Role / Timing Role: Real-time signal processor with 12-bit ADC oversampling, LPTIM-based sampling trigger, and DMA-accelerated data transfer to BLE SoC. Use Value: 76 µA/MHz efficiency and 1.14 Msps ADC allow continuous high-fidelity acquisition within 30 µA average system current budget. |
| Portable Medical Device | Asset Tracking Tag |
Use Scenario: Handheld pulse oximeter with LED drive, photodiode signal conditioning, and OLED display update every 2 seconds. IC Role / Device Role / Timing Role: Mixed-signal controller managing analog front-end biasing, synchronous LED pulsing (via TIM2), and display refresh via SPI. Use Value: Dual ultra-low-power comparators monitor photodiode saturation in real time, while 5V-tolerant I/Os drive OLED directly - eliminating 3 external components. | Use Scenario: GPS-enabled logistics tag reporting location every 6 hours using GNSS fix and cellular fallback. IC Role / Device Role / Timing Role: Power manager coordinating GNSS cold start, modem handshake, and deep-sleep sequencing via Stop mode with RAM retention. Use Value: 0.6 µA Stop + RTC + 8 KB RAM retention preserves session context and cryptographic keys across sleep cycles - enabling instant modem resume without re-authentication delay. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar ultra-low-power MCU applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| STM32L011K4U6 | 8 KB Flash, no EEPROM, identical package and peripherals - lacks 1 KB data EEPROM and some advanced timer features. | Suitable for simpler firmware with no persistent parameter storage requirement. | Select when EEPROM is unnecessary and BOM cost reduction is prioritized over field-upgrade flexibility. |
| EFM32ZG108F16 | Silicon Labs ARM Cortex-M0+, 16 KB Flash, 8 KB RAM, but no integrated EEPROM and higher typical Stop current (1.1 µA vs 0.6 µA). | Better RF integration support; weaker RTC retention capability in lowest power state. | Choose only if leveraging Simplicity Studio toolchain and existing EFM32 ecosystem - not drop-in compatible. |
Compared with STM32L031K4U6, STM32L011K4U6 trades EEPROM and enhanced timers for lower cost in fixed-function roles, while EFM32ZG108F16 offers alternative tooling but requires redesign to meet equivalent RTC+RAM retention targets.
Availability
STM32L031K4U6 is available at Aetrix Electronics and suitable for smart metering, wireless sensor networks, portable medical devices, and asset tracking tags requiring stable component supply across multi-year production cycles.
Supply support for STM32L031K4U6 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing microcontrollers, power management ICs, and MEMS sensors for industrial, automotive, and consumer markets.
The STM32L0 series targets ultra-low-power embedded applications, emphasizing energy efficiency, integrated analog peripherals, and long-term reliability in battery-operated and energy-harvesting systems.
FAQ
What is the maximum operating frequency of the STM32L031K4U6?
The STM32L031K4U6 runs at up to 32 MHz using its internal 16 MHz HSI oscillator with PLL multiplication or external crystal sources. Frequency scaling is dynamically managed via the PWR_CR register and voltage regulator settings to maintain stability across 1.65–3.6 V supply range.
Does the STM32L031K4U6 support USB or CAN interfaces?
No. The STM32L031K4U6 does not integrate USB or CAN physical layers or protocol controllers. Its communication peripherals are limited to USART, LPUART, SPI, and I²C. For USB connectivity, external bridge ICs (e.g., CP2102) or migration to STM32L053/073 series is required.
How many I/O pins are 5V tolerant on the STM32L031K4U6?
31 I/O pins are 5V tolerant, covering all GPIOs except those dedicated to analog functions (e.g., ADC inputs in certain configurations) and NRST. This is confirmed in Section 3.7 ("General-purpose inputs/outputs") and Table 53 ("I/O static characteristics") of DS10668 Rev 6.
What debug interface does the STM32L031K4U6 support?
The STM32L031K4U6 supports Serial Wire Debug (SW-DP) only - a 2-pin (SWDIO/SWCLK) interface compliant with ARM CoreSight. JTAG is not implemented. SW-DP enables full breakpoint, watchpoint, and memory access capabilities using standard tools like ST-Link v2/v3 or OpenOCD.
STM32L031K4U6 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- 32-UFQFN Exposed Pad
- Series:
- STM32L0
- Packaging:
- Tray
- Product Status:
- Active
- Programmable:
- Not Verified
- Core Processor:
- ARM® Cortex®-M0+
- Core Size:
- 32-Bit Single-Core
- Speed:
- 32MHz
- Connectivity:
- I2C, IrDA, LINbus, SPI, UART/USART
- Peripherals:
- Brown-out Detect/Reset, DMA, POR, PWM, WDT
- Number of I/O:
- 27
- Program Memory Size:
- 16KB (16K x 8)
- Program Memory Type:
- FLASH
- EEPROM Size:
- 1K x 8
- RAM Size:
- 8K x 8
- Voltage - Supply (Vcc/Vdd):
- 1.8V ~ 3.6V
- Data Converters:
- A/D 10x12b
- Oscillator Type:
- Internal
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
STM32L031K4U6 FAQ
1.How can I place an order for STM32L031K4U6 through Aetrix?
Please submit a Request for Quotation (RFQ) for STM32L031K4U6 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for STM32L031K4U6 reliable?
The price and inventory of STM32L031K4U6 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STM32L031K4U6 is usually 5 days.
3.What payment methods are accepted for STM32L031K4U6?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STM32L031K4U6 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for STM32L031K4U6?
STM32L031K4U6 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your STM32L031K4U6 order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for STM32L031K4U6?
For technical support, including STM32L031K4U6 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STM32L031K4U6 requirements.
6.How does Aetrix verify that STM32L031K4U6 is sourced from the original manufacturer or authorized distributors?
All STM32L031K4U6 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that STM32L031K4U6 meets industry standards.
7.What is the process for return or replacement of STM32L031K4U6?
All STM32L031K4U6 units undergo pre-shipment inspection (PSI). If there is an issue with STM32L031K4U6, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The STM32L031K4U6 part is unused and in its original packaging.
Return procedure for STM32L031K4U6:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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