STMicroelectronics STM32L552ZET6Q

Overview

STM32L552ZET6Q 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 and 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 STM32L552ZET6Q datasheet, STM32L552ZET6Q pinout, STM32L552ZET6Q application, or STM32L552ZET6Q equivalent, key selection criteria include TrustZone-enabled peripheral isolation, SMPS vs LDO power mode trade-offs, 114 GPIO count with 5 V tolerance, and dual-bank Flash for robust over-the-air updates in safety-critical embedded systems.

Technical Context

The device implements a dual-core security architecture: the Cortex-M33 core executes secure/non-secure code partitions enforced by SAU and GTZC, while TrustZone-aware peripherals (e.g., I/Os, memories, ADC, timers) are dynamically securable. Its FlexPowerControl system enables granular low-power mode selection - Shutdown (17 nA), Standby with RTC (222 nA), Stop 2 with RTC (3.16 μA), and Run mode down to 62 μA/MHz using the integrated SMPS step-down converter.

Timing and interface subsystems include three PLLs (system/USB/audio), OCTOSPI for high-speed external memory, FDCAN for deterministic fieldbus communication, UCPD for USB Type-C™ power delivery control, and two SAIs supporting I²S/TDM audio streaming. The ART Accelerator with 8 KB instruction cache ensures zero-wait-state execution from Flash at 110 MHz.

Key Specifications

Pinout & Package

LQFP144 (20 × 20 mm) package with 144 leads, 0.5 mm pitch, and exposed thermal pad. Designed for high I/O density and thermal reliability in industrial and medical applications.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STM32U575ZIT6Q, the STM32L552ZET6Q trades peak performance for superior sub-μA standby efficiency and lower BOM cost via integrated SMPS; versus RA4M3GJ32FHB, it delivers finer-grained TrustZone enforcement and 3.5× lower Stop-mode current - critical for decade-long battery operation.

Availability

STM32L552ZET6Q is available at Aetrix Electronics and suitable for industrial wireless sensors, secure medical wearables, smart utility meters, and USB-C powered IoT gateways requiring stable component supply across extended product lifecycles.

Supply support for STM32L552ZET6Q 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 chips for industrial, automotive, and consumer markets.

The STM32L5 series is engineered for ultra-low-power, high-security embedded applications - combining Arm TrustZone with flexible power architectures to meet PSA Certified Level 3 and IEC 62443 requirements in constrained environments.

FAQ

What is the maximum operating frequency and corresponding power mode configuration?

The STM32L552ZET6Q achieves 110 MHz maximum CPU frequency in Run mode with the ART Accelerator enabled and SMPS configured in bypass mode (VDD = 3.3 V). At this speed, typical current consumption is 106 μA/MHz in LDO mode or 62 μA/MHz in SMPS step-down mode. Frequency scaling is managed via the RCC and voltage regulator settings per RM0438 Section 7.3.3.

How does TrustZone implementation differ from standard Cortex-M33 deployment?

This MCU extends baseline TrustZone with ST-specific hardware: Global TrustZone Controller (GTZC) enforces memory region security attributes, TrustZone Security Controller (TZSC) locks peripheral registers, and securable I/Os allow pin-level isolation. Unlike generic implementations, GTZC supports dynamic reconfiguration of secure/non-secure boundaries at runtime without reset - validated in AN5402 and RM0438 Chapter 3.7.

Can the integrated SMPS replace an external DC-DC converter in all designs?

Yes - the embedded SMPS supports 1.62–3.6 V input and delivers up to 200 mA at adjustable output (0.8–1.45 V), eliminating need for external buck converters in most battery-powered applications. However, designs requiring >200 mA load current or ultra-low output ripple (<10 mVpp) must retain external regulation per DS12737 Section 3.9.4 and AN5213.

What debug interfaces are supported and what are their security implications?

Serial Wire Debug (SWD) and JTAG are supported, but both are disabled in RDP Level 2 (full readout protection). In RDP Level 1, SWD access is permitted only in secure debug mode after authentication via secure boot. ETM trace is available only in non-secure world unless explicitly enabled in secure firmware - detailed in RM0438 Section 3.42 and AN5347.