STMicroelectronics STM32L431KCU6TR

Overview

STM32L431KCU6TR from STMicroelectronics is an ultra-low-power Arm® Cortex®-M4 32-bit MCU with FPU, operating up to 80 MHz and delivering 100 DMIPS. It integrates 256 KB Flash, 64 KB SRAM (16 KB with hardware parity), and rich analog peripherals including a 12-bit 5 Msps ADC, dual 12-bit DACs, one op-amp with PGA, and two ultra-low-power comparators. It targets battery-powered IoT sensors and portable medical devices requiring sub-µA standby operation and RTC-backed data logging.

For engineers reviewing the STM32L431KCU6TR datasheet, STM32L431KCU6TR pinout, STM32L431KCU6TR application, or STM32L431KCU6TR equivalent, key selection criteria include verified 28 nA Standby current, 4 µs wakeup from Stop mode, LPUART wake capability, 5 V-tolerant I/Os on selected pins, and UFBGA64 (5×5 mm) package compatibility with space-constrained PCB layouts.

Technical Context

The device implements FlexPowerControl architecture with seven low-power modes-Shutdown (8 nA), Standby (28 nA), Stop 2 (1.0 µA), and Run (84 µA/MHz)-enabled by independent voltage regulators, adaptive power gating, and BOR circuitry. Its ART Accelerator™ eliminates Flash wait states at 80 MHz, while the interconnect matrix decouples bus arbitration for deterministic peripheral access.

Core timing relies on multiple clock sources: HSE (4–48 MHz), LSE (32.768 kHz), HSI16 (±1%), MSI (auto-trimmed to ±0.25%), and HSI48 for USB/SAI. Dual PLLs support simultaneous system, audio, and ADC clock domains, and the SAI interface enables I²S/TDM audio streaming without CPU intervention.

Key Specifications

Pinout & Package

STM32L431KCU6TR uses a 64-ball Ultra-Fine-Pitch Ball Grid Array (UFBGA64) package with 0.5 mm ball pitch and 5×5 mm body size. The package supports 51 general-purpose I/Os (most 5 V-tolerant), 14 dedicated analog inputs, and 10 power/ground balls distributed for low-noise analog and digital domain separation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar ultra-low-power Cortex-M4 MCU applications.

Compared with STM32L431KCU6TR, STM32L432KCU6 trades Flash capacity and CAN/SDMMC for integrated USB, while STM32L476RGV6 expands memory and multimedia features at the cost of power efficiency-making the KCU6TR optimal for constrained, sensor-centric designs prioritizing sub-µA standby and analog integration.

Availability

STM32L431KCU6TR is available at Aetrix Electronics and suitable for wearable health monitors, smart utility meters, industrial wireless sensor nodes, and portable medical diagnostic tools requiring stable component supply across multi-year production cycles.

Supply support for STM32L431KCU6TR 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, MEMS, and automotive semiconductors since 1987.

The STM32L4 series targets ultra-low-power embedded applications demanding high performance-per-milliwatt, with design focus on energy harvesting, battery longevity, and secure firmware execution in IoT endpoints and portable medical equipment.

FAQ

What is the maximum operating frequency and corresponding performance metric?

The STM32L431KCU6TR operates at up to 80 MHz using its Arm Cortex-M4 core with FPU. At this frequency, it achieves 100 DMIPS (Dhrystone 2.1) and 273.55 CoreMark® (3.42 CoreMark/MHz), validated with ART Accelerator™ enabled and zero-wait-state Flash execution. These metrics reflect real-world integer and floating-point throughput in sensor fusion and control-loop applications.

Does this MCU support hardware cryptographic acceleration?

No, the STM32L431KCU6TR does not include dedicated cryptographic accelerators (e.g., AES, SHA, PKA). It relies on software libraries (STM32CubeL4 Crypto package) for encryption. However, its true RNG (NIST SP800-90B compliant) and memory firewall provide foundational security for key generation and code protection in resource-constrained deployments.

Which low-power mode retains RTC and backup registers with lowest current draw?

VBAT mode draws 200 nA and maintains RTC operation and 32×32-bit backup registers using an external coin cell or supercapacitor on the VBAT pin. This mode fully powers down the main regulator while preserving timekeeping and critical state-enabling decade-scale battery life in time-sensitive monitoring applications.

Can the UFBGA64 package be hand-soldered or reworked reliably?

The UFBGA64 (5×5 mm, 0.5 mm pitch) requires precision reflow profiling and X-ray inspection due to hidden solder joints. While possible with stencil-controlled paste deposition and nitrogen-reflow ovens, STMicroelectronics recommends automated placement and reflow for production. For prototyping, use ST's NUCLEO-L432KC or STM32L431RCT6-based boards with QFP packages instead.