STMicroelectronics STM32L552ZET6

Overview

STM32L552ZET6 from STMicroelectronics is an ultra-low-power Arm® Cortex®-M33 32-bit microcontroller with TrustZone® security, FPU, and SMPS support. It delivers 165 DMIPS at up to 110 MHz, integrates 512 KB dual-bank Flash (read-while-write), 256 KB SRAM (64 KB with hardware parity), and operates from 1.71 V to 3.6 V across –40 °C to 125 °C. It targets secure, battery-constrained edge nodes such as industrial wireless sensors and medical wearables requiring certified firmware integrity and sub-µA standby.

For engineers reviewing the STM32L552ZET6 datasheet, STM32L552ZET6 pinout, STM32L552ZET6 application, or STM32L552ZET6 equivalent, key selection considerations include TrustZone-enforced peripheral isolation, SMPS vs LDO power mode trade-offs, 114 GPIO count with independent supply options, and verified ULPMark-CP® 370 performance for energy-constrained firmware validation.

Technical Context

The device implements a dual-core security architecture: the Cortex-M33 core executes in Secure/Non-secure states enforced by TrustZone®, while the GTZC (Global TrustZone Controller) gates access to memories, peripherals, and I/Os via SAU and TZSC registers. Boot flow begins from ROM with immutable root of trust, supporting SFI (Secure Firmware Installation) via embedded RSS and TF-M–compliant secure firmware upgrades.

Power management integrates three configurable LDO output ranges and an on-chip SMPS step-down converter enabling 62 µA/MHz run-mode efficiency at 3 V. Low-power modes include Shutdown (17 nA), Standby with RTC (222 nA), and Stop 2 with RTC (3.16 µA), all featuring <5 µs wakeup latency and brownout reset in all active states except Shutdown.

Key Specifications

Pinout & Package

LQFP144 package (20 × 20 mm, 0.5 mm pitch) with exposed thermal pad; RoHS-compliant, moisture sensitivity level MSL3.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STM32L552ZET6, STM32U575ZIT6 trades ultra-low-power efficiency for higher performance and expanded security features, while LPC55S69JBD100 offers broader connectivity at the cost of 75% higher active current - making STM32L552ZET6 optimal for multi-year battery operation where security and energy are co-primary constraints.

Availability

STM32L552ZET6 is available at Aetrix Electronics and suitable for industrial wireless sensor nodes, portable medical monitors, smart utility meters, and secure edge gateways requiring stable component supply across extended product lifecycles.

Supply support for STM32L552ZET6 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 devices for industrial, automotive, and consumer markets.

The STM32L5 series is engineered specifically for ultra-low-power, security-critical embedded applications - combining Arm TrustZone with silicon-proven power gating and SMPS integration to address battery longevity and firmware integrity in certified IoT endpoints.

FAQ

What is the maximum operating frequency and how is it achieved?

The STM32L552ZET6 achieves 110 MHz maximum CPU frequency using its internal multispeed oscillator auto-trimmed by the 32.768 kHz LSE crystal, delivering better than ±0.25% accuracy. This eliminates need for external high-frequency crystal while maintaining timing precision for USB, audio, and real-time control tasks.

Does this MCU support secure boot from external memory?

No - secure boot is restricted to internal Flash, system memory, or SRAM. External memory (OCTOSPI, FSMC) cannot serve as a trusted boot source due to lack of hardware authentication path; however, external code can be loaded into secure SRAM after verification via HASH and TRNG-validated signature check.

How many independent power domains does the LQFP144 package support?

The LQFP144 package supports three independent power domains: VDD/VSS (digital core), VDDA/VSSA (analog), and VDDIO2 (I/O bank 2). This allows interfacing with 1.8 V logic while maintaining 3.3 V analog supply and 1.08–3.6 V programmable I/O voltage - critical for mixed-voltage system integration.

Can the SMPS be used simultaneously with the internal LDO?

No - the SMPS and LDO are mutually exclusive power regulation options. The device boots using LDO by default; SMPS must be explicitly enabled via PWR_CR3 register and requires external inductor/capacitor components. Switching between them is software-controlled but not concurrent.