STMicroelectronics STM32U031K8U6

Overview

STM32U031K8U6 from STMicroelectronics is an ultra-low-power 32-bit Arm® Cortex®-M0+ microcontroller operating up to 56 MHz, featuring 64-Kbyte flash memory, 12-Kbyte SRAM with hardware parity, and integrated analog peripherals including a 12-bit ADC, 12-bit DAC, operational amplifier, and ultra-low-power comparator - deployed in battery-powered IoT sensors and portable medical monitors.

For engineers reviewing the STM32U031K8U6 datasheet, STM32U031K8U6 pinout, STM32U031K8U6 application, or STM32U031K8U6 equivalent, key selection criteria include VBAT mode current (130 nA), Stop 2 mode consumption (630 nA with RTC), 53 GPIOs (most 5 V-tolerant), and support for PSA Level 1/SESIP Level 3 security certifications.

Technical Context

The STM32U031K8U6 implements an ART Accelerator with 1-Kbyte instruction cache enabling 0-wait-state execution from flash at 56 MHz, paired with a dual-regulator power architecture (main + low-power LPR) that dynamically selects VCORE supply based on active low-power mode. Its Cortex-M0+ core includes MPU support and deterministic NVIC interrupt handling.

Analog subsystem operation is isolated via independent VDDA (1.62–3.6 V) and VBAT (1.55–3.6 V) domains, enabling simultaneous RTC retention (with 9×32-bit backup registers), capacitive sensing (18 channels), and rail-to-rail OPAMP operation - all while maintaining 4 μs wake-up from Stop mode and brownout reset (BOR) with four configurable thresholds.

Key Specifications

Pinout & Package

STM32U031K8U6 is housed in a 32-pin UFQFPN package (5 × 5 mm, 0.5 mm pitch) with exposed thermal pad, compliant with ECOPACK2 environmental standards. Pin functions are validated per DS14581 Rev 2 (pages 32–41) and ST's official pinout diagrams for UFQFPN32 variant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STM32L031K6T6, the STM32U031K8U6 adds DAC, OPAMP, and 32 MHz higher CPU frequency at identical package size; versus EFM32PG12B500F1024GL125, it trades raw memory capacity for tighter analog integration, smaller footprint, and lower system BOM cost in space-constrained sensor nodes.

Availability

STM32U031K8U6 is available at Aetrix Electronics and suitable for wearable health monitors, smart utility meters, wireless sensor nodes, and portable diagnostic tools requiring stable component supply across extended product lifecycles.

Supply support for STM32U031K8U6 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 automotive semiconductors since 1987.

The STM32U0 series targets ultra-low-power embedded applications demanding long battery life, security certification readiness, and high analog integration - specifically optimized for IoT edge nodes and portable medical devices.

FAQ

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

The STM32U031K8U6 operates at up to 56 MHz in Run mode with LDO regulator enabled, consuming 52 μA/MHz. At full speed, this equates to approximately 2.9 mA total core current, verified per DS14581 Rev 2 Section 6.3.1 (typical current vs. frequency curves). This value excludes I/O and analog peripheral current, which scale independently based on active configuration.

Does the device support hardware-based secure boot and cryptographic operations?

Yes - the STM32U031K8U6 includes dedicated hardware for Secure Boot with immutable root-of-trust, True Random Number Generation (TRNG) certified to NIST SP 800-90B candidate level, and Hardware Protection Feature (HDP) for flash memory isolation. It is designed to meet Arm® PSA Level 1 and SESIP Level 3 certification requirements, with no software-only fallback paths for critical security functions.

How many capacitive sensing channels are supported, and what topologies do they enable?

The STM32U031K8U6 supports up to 18 capacitive sensing channels via its CSD peripheral, validated for touchkey, linear slider, and rotary encoder topologies. Channel mapping is fixed per UFQFPN32 pinout (PA0–PA7, PB0–PB11, PF0–PF1), and all channels operate concurrently with automatic scan sequencing and noise immunity filtering - eliminating need for external charge-transfer ICs or custom PCB layout tuning.

What are the valid voltage ranges for VDDA and VBAT, and how do they interact during power loss?

VDDA accepts 1.62–3.6 V (for ADC/COMP) or 1.80–3.6 V (for DAC/OPAMP); VBAT accepts 1.55–3.6 V. During VDD loss, an internal switch automatically transfers RTC and backup register power from VDD/VDDA to VBAT - preserving timekeeping and nonvolatile state. The VBAT domain remains fully functional down to 1.55 V, with RTC accuracy maintained via LSE oscillator calibration.