STMicroelectronics STM32L031G6U3

Overview

STM32L031G6U3 from STMicroelectronics is an ultra-low-power 32-bit Arm® Cortex®-M0+ microcontroller in a 28-pin UFQFPN (4×4 mm) package, featuring 32 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 STM32L031G6U3 datasheet, STM32L031G6U3 pinout, STM32L031G6U3 application, or STM32L031G6U3 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 - all critical for energy-constrained embedded designs requiring long-term autonomy and robust peripheral integration.

Technical Context

The STM32L031G6U3 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 power/performance trade-offs validated down to 1.65 V supply.

Peripheral interconnect is managed via an AHB/APB matrix supporting concurrent DMA transfers (7-channel controller) to ADC, USART, SPI, I2C, and timers. Analog subsystem includes two independent comparators with window mode and wake-up capability, plus temperature sensor and internal voltage reference (VREFINT) - all functional at minimum supply voltage.

Key Specifications

Pinout & Package

STM32L031G6U3 uses a 28-pin Ultra-Fine Pitch Quad Flat No-lead (UFQFPN) package measuring 4 × 4 mm with 0.5 mm pitch. The package is RoHS-compliant and ECOPACK®2 certified, optimized for space-constrained PCB layouts and automated assembly.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar ultra-low-power MCU applications.

Compared with STM32L011K4T6, the STM32L031G6U3 adds EEPROM and doubles Flash for secure OTA updates; versus STM32L051K8U6, it trades package size and memory for lower BOM cost and smaller board area - making it optimal for compact, cost-sensitive, long-life battery devices.

Availability

STM32L031G6U3 is available at Aetrix Electronics and suitable for smart metering, wireless sensor networks, industrial predictive maintenance, and medical wearable patches requiring stable component supply across extended product lifecycles.

Supply support for STM32L031G6U3 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, MEMS, and automotive semiconductors since 1987.

The STM32L0 series targets ultra-low-power embedded applications, emphasizing energy efficiency, security, and integration for battery-operated IoT endpoints - with the L031 variant optimized for cost-sensitive, space-constrained designs needing robust analog peripherals and ECC memory.

FAQ

What is the maximum operating frequency of the STM32L031G6U3, and how is it achieved?

The STM32L031G6U3 achieves a maximum CPU frequency of 32 MHz using its internal 16 MHz HSI oscillator multiplied by the integrated PLL. Dynamic voltage scaling adjusts the core voltage based on frequency, enabling full-speed operation down to 1.65 V supply. External crystal oscillators (up to 25 MHz) may also feed the PLL for higher precision timing.

Does the STM32L031G6U3 support hardware encryption or secure boot features?

No, the STM32L031G6U3 does not include hardware cryptographic accelerators (AES, SHA, PKA) or secure boot ROM. It relies on software-based encryption libraries and standard flash write protection mechanisms. For secure firmware updates, developers must implement authenticated bootloaders using external secure elements or leverage ST's STM32L07x/L08x series which integrate AES-128 and public-key acceleration.

Can the STM32L031G6U3 drive an external 32.768 kHz crystal for RTC accuracy?

Yes, the STM32L031G6U3 supports external 32.768 kHz crystals connected to PC14 (OSC32_IN) and PC15 (OSC32_OUT) pins. The LSE oscillator circuit includes automatic gain control and calibration registers to compensate for crystal aging and temperature drift, achieving ±20 ppm accuracy over –40 to +85 °C when paired with a suitable crystal and load capacitors.

How many I/O pins support wake-up from Stop or Standby mode?

The STM32L031G6U3 supports wake-up from Stop mode on up to 16 lines (all GPIOs configurable as EXTI sources), and from Standby mode on 2 dedicated pins (PA0 and PC13). Wake-up latency is 5 µs from Flash and sub-10 µs from SRAM, verified per DS10668 Rev 6 Section 6.3.36, enabling rapid response to external events without sacrificing ultra-low-power sleep states.