STMicroelectronics STM32U535REI6

Overview

STM32U535REI6 from STMicroelectronics is an ultra-low-power Arm® Cortex®-M33 microcontroller with TrustZone® security, 512 KB flash, 274 KB SRAM, and integrated FPU-designed for secure, battery-operated edge nodes in industrial sensing and medical wearables. It delivers 240 DMIPS at up to 160 MHz, supports LPBAM autonomous peripheral operation down to Stop 2 mode, and features 90 nA Shutdown current with 23 wake-up pins.

For engineers reviewing the STM32U535REI6 datasheet, STM32U535REI6 pinout, STM32U535REI6 application, or STM32U535REI6 equivalent, key selection criteria include TrustZone-enabled secure boot, sub-µA low-power modes (e.g., 370 nA Standby with RTC), dual 14-/12-bit ADCs with hardware oversampling, CAN FD interface, and Octo-SPI support for external memory expansion.

Technical Context

The STM32U535REI6 implements a dual-bank flash architecture with ECC and read-while-write capability, enabling secure over-the-air firmware updates without runtime interruption. Its ART Accelerator includes 8-Kbyte instruction cache and 4-Kbyte data cache, allowing zero-wait-state execution from flash and external memories at 160 MHz.

Power management integrates both LDO and SMPS step-down converters with dynamic voltage scaling and on-the-fly switching-critical for optimizing energy efficiency across active and deep-sleep modes. The TrustZone security subsystem enforces hardware-isolated secure/non-secure worlds, with securable I/Os, memories, peripherals, and a root-of-trust via unique boot entry and HDP protection.

Key Specifications

Pinout & Package

LQFP48 (7 × 7 mm, 0.5 mm pitch) package with 42 general-purpose I/Os, 3 power supply pins (VDD, VSS, VDDA), 2 reset/debug pins (NRST, SWDIO/SWCLK), and dedicated functional pins for RTC, VBAT, USB, and crystal oscillators.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STM32U535REI6, the STM32U575 offers higher memory density and advanced crypto but demands more board area and power; the RA4M3 provides competitive performance at lower cost but lacks TrustZone isolation and sub-µA low-power modes essential for decade-long battery operation.

Availability

STM32U535REI6 is available at Aetrix Electronics and suitable for industrial sensor nodes, portable medical devices, smart utility meters, and asset tracking modules requiring stable component supply across extended product lifecycles.

Supply support for STM32U535REI6 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 STM32U5 series is ST's flagship ultra-low-power secure MCU line targeting battery-powered IoT endpoints, emphasizing sub-µA power states, PSA Certified Level 3 security, and integrated analog/motor control peripherals for rapid time-to-market in certified edge applications.

FAQ

What is the maximum operating temperature rating for STM32U535REI6?

The STM32U535REI6 is qualified for industrial operation from –40 °C to +85 °C. An extended version (STM32U535REI6Y) supports –40 °C to +125 °C ambient temperature, validated per AEC-Q100 Grade 1 for under-hood automotive use cases requiring enhanced thermal robustness.

Does STM32U535REI6 support hardware-based secure boot with public-key verification?

Yes. The device implements a hardware-rooted secure boot flow using immutable ROM code that verifies signed firmware images via ECDSA-P256 before execution. Public keys are stored in the 512-byte OTP area, and signature validation leverages the embedded HASH and PKA accelerators-meeting PSA Certified Level 3 requirements.

Can the Octo-SPI interface operate in memory-mapped mode while the CPU executes from external flash?

Yes. The Octo-SPI controller supports memory-mapped execution (XIP) from external NOR/NAND/DRAM devices. When enabled, the ART Accelerator caches instructions fetched over Octo-SPI, achieving zero-wait-state execution at up to 133 MHz-allowing code expansion beyond on-chip flash without performance penalty.

How many independent power domains does STM32U535REI6 support for mixed-signal isolation?

The MCU features three independent power domains: VDD/VSS (digital core), VDDA/VSSA (analog), and VBAT (backup). Each has dedicated regulators, decoupling requirements, and voltage monitoring-enabling strict noise separation between high-speed digital logic and precision analog circuits like the 14-bit ADC and OPAMP.