STMicroelectronics STM32U031R6I6

Overview

STM32U031R6I6 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 (0.4 µs conversion), 12-bit DAC, operational amplifier with PGA, and ultra-low-power comparator. It targets battery-powered IoT sensors and portable medical devices requiring sub-100-nA standby operation.

For engineers reviewing the STM32U031R6I6 datasheet, STM32U031R6I6 pinout, STM32U031R6I6 application, or STM32U031R6I6 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 Arm® PSA Level 1 and SESIP Level 3 security certifications.

Technical Context

The STM32U031R6I6 implements an adaptive real-time (ART) accelerator enabling 0-wait-state execution from flash at 56 MHz, paired with a 1-Kbyte instruction cache. Its power architecture integrates dual regulators (main and low-power) and supports five low-power modes-Shutdown (16 nA), Standby (30 nA without RTC), Stop 2 (515–630 nA), Low-power Run (2 MHz max), and Sleep-with 4 wake-up pins and 4 μs wake-up latency from Stop.

Analog subsystems operate on independent supplies: VDDA (1.62–3.6 V) powers ADC/DAC/OPAMP/comparator, while VBAT (1.55–3.6 V) sustains RTC and 9×32-bit backup registers. Security includes robust RDP (3-level), HDP, secure boot, TRNG (NIST SP 800-90B candidate), and 5 passive anti-tamper pins.

Key Specifications

Pinout & Package

LQFP64 (10 × 10 mm, ECOPACK2-compliant) package with exposed thermal pad; 64-pin layout supporting full peripheral mapping including VDD/VSS pairs, VDDA/VSSA analog separation, dedicated VBAT, 5 tamper inputs, and 53 general-purpose I/Os.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STM32L031K6T6, the STM32U031R6I6 adds DAC, OPAMP, and 64-KB flash for richer analog integration and firmware flexibility; versus STM32U535RBT6, it achieves 36× lower Standby current at the cost of CPU performance and security depth - making it optimal for energy-constrained, analog-intensive edge endpoints.

Availability

STM32U031R6I6 is available at Aetrix Electronics and suitable for wearable health monitors, smart utility meters, industrial wireless sensor nodes, and portable diagnostic devices requiring stable component supply and long-term lifecycle assurance.

Supply support for STM32U031R6I6 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 STM32U0 series is ST's entry-level ultra-low-power MCU line targeting battery-operated IoT endpoints, emphasizing sub-100-nA shutdown current, integrated analog, and PSA-certifiable security - distinct from the higher-performance STM32L0/L4 or secure STM32U5 families.

FAQ

What is the minimum supply voltage for reliable operation of the STM32U031R6I6?

The STM32U031R6I6 operates reliably from 1.71 V to 3.6 V on VDD. Below 1.71 V, brownout reset (BOR) activates to prevent undefined behavior; the internal LDO regulator maintains stable VCORE down to this threshold. VDDA must be ≥1.62 V for ADC/COMP or ≥1.80 V for DAC/OPAMP operation.

Does the STM32U031R6I6 support hardware-accelerated cryptography?

No - the STM32U031R6I6 does not include a cryptographic accelerator. It provides True Random Number Generation (TRNG) certified to NIST SP 800-90B candidate level and supports secure boot via RDP/HDP, but AES/SHA operations require software implementation. For hardware crypto, consider the STM32U5 series.

How many capacitive sensing channels does the STM32U031R6I6 support, and what is their resolution?

The STM32U031R6I6 supports up to 18 capacitive sensing channels using its built-in CSD (Capacitive Sensing Driver). Resolution is configurable up to 16-bit via oversampling, enabling robust touchkey, linear slider, and rotary encoder implementations without external components.

Can the STM32U031R6I6 retain SRAM content during Standby mode?

Yes - SRAM2 (4 Kbytes) retains data in Standby mode when configured via PWR_CR2.SRAME bit. SRAM1 (8 Kbytes) is lost unless explicitly preserved using the PWR_CR1.RRS bit before entering Standby. Backup registers and RTC remain active with VBAT supply.