STMicroelectronics STM32L431CBU6TR

Overview

STM32L431CBU6TR from STMicroelectronics is an ultra-low-power Arm® Cortex®-M4 32-bit MCU with FPU, operating up to 80 MHz, featuring 128 KB Flash, 64 KB SRAM, and integrated analog peripherals including a 12-bit 5 Msps ADC, dual 12-bit DACs, and an operational amplifier with PGA. It supports 28 nA Standby mode with RTC, 84 µA/MHz run efficiency, and is qualified for industrial temperature range (–40 °C to +85 °C), targeting battery-powered sensor nodes and portable medical devices.

For engineers reviewing the STM32L431CBU6TR datasheet, STM32L431CBU6TR pinout, STM32L431CBU6TR application, or STM32L431CBU6TR equivalent, key selection criteria include low-power mode timing (4 µs wakeup from Stop), FlexPowerControl architecture, ART Accelerator™ enabling zero-wait-state Flash execution, and hardware parity on 16 KB SRAM - all critical for energy-constrained embedded control designs.

Technical Context

The STM32L431CBU6TR implements an Arm Cortex-M4 core with FPU and Adaptive Real-Time Accelerator (ART) for deterministic Flash execution at 80 MHz. Its power architecture integrates five low-power modes (Shutdown, Standby, Stop 0/1/2), each with distinct peripheral retention and wakeup latency profiles - e.g., Stop 2 retains SRAM and LPUART while consuming 1.0 µA.

Analog subsystem includes independent supply domains: one 12-bit ADC (5 Msps, hardware oversampling to 16-bit), two 12-bit DACs with sample-and-hold, one rail-to-rail op-amp with programmable gain amplifier (PGA), and two ultra-low-power comparators - all configurable without CPU intervention via autonomous peripherals like LP timers and DMA.

Key Specifications

Pinout & Package

STM32L431CBU6TR uses the UFQFPN32 package: 5 mm × 5 mm body, 0.5 mm lead pitch, exposed thermal pad, RoHS-compliant and ECOPACK2® certified. Pin count is 32, with 26 user I/Os (most 5 V-tolerant), dedicated reset, VDD/VSS, VREF+/VREF–, VBAT, and multiple power/ground pins for noise isolation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STM32L431CBU6TR, STM32L432KCU6 adds USB but removes CAN and SDMMC - making it ideal for USB-peripheral edge devices, while STM32L412CBU6 sacrifices analog richness and connectivity for lower BOM cost in basic telemetry applications.

Availability

STM32L431CBU6TR is available at Aetrix Electronics and suitable for wearable health monitors, smart gas sensor nodes, industrial predictive maintenance edge nodes, and portable medical infusion pumps requiring stable component supply across multi-year production cycles.

Supply support for STM32L431CBU6TR 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 ICs, sensors, and automotive-grade components since 1987.

The STM32L4 series targets ultra-low-power embedded applications demanding rich analog integration, real-time performance, and extended battery life - optimized for IoT endpoints, portable medical, and industrial monitoring systems.

FAQ

What is the maximum operating frequency and associated power consumption in Run mode?

The STM32L431CBU6TR operates at up to 80 MHz with ART Accelerator enabled. At this frequency, typical Run mode current is 272 µA/MHz (21.76 mA total) with all peripherals active and Flash execution - verified per DS11453 Rev 3 Table 26. Voltage scaling (VOS range 0–2) allows trade-offs between speed and current, down to 1.28 µA in Stop 2 with RTC.

Does STM32L431CBU6TR support hardware cryptographic acceleration?

No. The STM32L431CBU6TR does not integrate dedicated cryptographic accelerators (e.g., AES, PKA, HASH). It relies on software libraries (STM32CubeL4) for crypto operations. For hardware-accelerated security, consider STM32L5xxx or STM32U5xxx families with AES-256, PKA, and secure boot ROM.

What debug interfaces are supported, and what pins do they require?

It supports Serial Wire Debug (SWD) using SWCLK and SWDIO pins (PA14/PA13), and JTAG via TCK/TMS/TDI/TDO/TRESET (shared with SWD pins). No additional pins are required beyond the standard 4-pin SWD header. Embedded Trace Macrocell™ (ETM) is present but requires SWO pin (PA10) for trace output - not available in UFQFPN32 due to pin count constraints.

Can the internal op-amp drive a 10 kΩ load with rail-to-rail output swing?

Yes. Per DS11453 Rev 3 Section 6.3.22, the op-amp delivers rail-to-rail output swing into ≥10 kΩ loads with ±10 mV accuracy at VDD = 3.3 V. Output current capability is ±30 mA short-circuit protected, and gain error is ≤1.5% over temperature (–40 °C to +85 °C) when configured in non-inverting mode with PGA enabled.