STMicroelectronics STM32L031G6U7STR

Overview

STM32L031G6U7STR from STMicroelectronics is an ultra-low-power 32-bit Arm® Cortex®-M0+ microcontroller with 32 KB Flash, 8 KB SRAM, 1 KB EEPROM, 12-bit ADC (1.14 Msps), and operating voltage range of 1.65–3.6 V. It delivers 0.95 DMIPS/MHz performance at up to 32 MHz and supports -40 to +125 °C industrial temperature operation. Used in battery-powered sensor nodes requiring long-term autonomous operation with RTC and wake-up capability.

For engineers reviewing the STM32L031G6U7STR datasheet, STM32L031G6U7STR pinout, STM32L031G6U7STR application, or STM32L031G6U7STR equivalent, key selection criteria include standby current (0.23 µA), 5 µs Flash wakeup time, 31 I/Os with 5V tolerance, and integrated ECC for Flash and EEPROM - critical for firmware integrity in field-deployed IoT edge devices.

Technical Context

The STM32L031G6U7STR implements a dual-voltage domain architecture with programmable voltage scaling (PVS) enabling dynamic power optimization across Run, Sleep, Stop, and Standby modes. Its clock system integrates multiple oscillators: 16 MHz factory-trimmed HSI (±1%), 32 kHz LSE for RTC calibration, and MSI (65 kHz–4.2 MHz) for low-power peripheral operation.

Core peripherals include a 7-channel DMA controller servicing ADC, USART, SPI, I2C, and timers; two ultra-low-power comparators with window mode and wake-up capability down to 1.65 V; and a CRC calculation unit with 96-bit unique ID. All I/Os support interrupt-on-change and configurable pull-up/pull-down.

Key Specifications

Pinout & Package

STM32L031G6U7STR uses the UFQFPN28 (4 × 4 mm, 0.5 mm pitch) package with 25 usable pins (including VDD, VSS, NRST, BOOT0, and SWDIO/SWCLK). This compact, lead-free ECOPACK®2-compliant package supports reflow soldering and high-density PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STM32L011K4T6 and EFM32HG309F64G, the STM32L031G6U7STR uniquely combines on-die ECC-protected EEPROM, sub-µA standby, and 5V-tolerant I/Os in a 4×4 mm package - making it optimal for space-constrained, maintenance-free deployments where data persistence and mixed-voltage interfacing are mandatory.

Availability

STM32L031G6U7STR is available at Aetrix Electronics and suitable for smart utility metering, wireless sensor nodes, medical wearable patches, and asset tracking beacons requiring stable component supply across multi-year production cycles.

Supply support for STM32L031G6U7STR 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, sensors, and analog products for industrial, automotive, and consumer markets.

The STM32L0 series targets ultra-low-power embedded applications demanding extended battery life, robust firmware integrity, and seamless integration of analog peripherals - optimized for IoT endpoints, portable medical devices, and energy-harvesting systems.

FAQ

What is the maximum operating frequency and associated power consumption in Run mode?

The STM32L031G6U7STR operates up to 32 MHz with 76 µA/MHz typical current draw at 3.0 V and 25 °C. At full speed, total active current is approximately 2.43 mA - verified per DS10668 Rev 6 Table 24. Dynamic voltage scaling allows lower VDD in low-frequency modes to further reduce power.

Does this MCU support hardware encryption or secure boot features?

No. The STM32L031G6U7STR does not integrate hardware AES, SHA, or secure boot engines. It supports software-based cryptographic libraries and relies on write-protection sectors and ROP (read-out protection) Level 1/2 for basic firmware confidentiality - confirmed in Section 3.9 (Memories) and RM0377 Reference Manual.

Can the internal 32 kHz LSE oscillator be used for precise RTC timekeeping without an external crystal?

No. The LSE oscillator requires an external 32.768 kHz quartz crystal connected to OSC32_IN/OSC32_OUT pins to achieve ±20 ppm accuracy. The internal LSI (37 kHz RC) is not calibrated and drifts significantly with voltage/temperature - unsuitable for time-critical RTC applications per Section 6.3.6 and 6.3.7.

How many I/O pins support 5V tolerance, and which ones are they?

In the UFQFPN28 package, 22 GPIOs (PA0–PA15, PB0–PB6) are 5V tolerant when configured as inputs. This is explicitly defined in Table 15 (Pin definitions) and Section 6.3.13 of DS10668 Rev 6. Pins like NRST, BOOT0, and SWDIO are not 5V tolerant and require level-shifting if driven above VDD.