STM32L431RCT6 How-To Guide: Design with the 80 MHz Cortex-M4 MCU

To design with the STM32L431RCT6, start with its verified core specs: an Arm Cortex-M4 with FPU running at up to 80 MHz, 256 KB Flash, 64 KB SRAM, a 1.71V to 3.6V supply range, and a 64-pin LQFP (10x10 mm) package. This ultra-low-power MCU from STMicroelectronics supports Sleep, Low-power run, Low-power sleep, Stop 0/1/2, Standby, and Shutdown modes, with Standby-with-RTC current as low as 3.4 uA and Shutdown current as low as 100 nA. For battery-powered IoT nodes, choose the STM32L431RCT6 when you need DSP-class performance and rich analog peripherals: a 12-bit ADC with up to 16 channels, a 12-bit DAC with 2 channels, and interfaces including USART, SPI, I2C, USB 2.0 FS, CAN 2.0B, and SAI.

What Are the Verified STM32L431RCT6 Specifications?

All values in this section are anchored to the XAIPART product database for STM32L431RCT6, verified as of 2026-08-19.

The device is built by STMicroelectronics on an advanced 90nm process, according to the product description, and delivers 100 DMIPS at 80 MHz according to the verified FAQ. It includes a memory protection unit (MPU), a nested vectored interrupt controller (NVIC), a 14-channel DMA controller, and a real-time clock. The Flash supports read-while-write, allowing firmware updates without halting the system. Download the official datasheet here: STM32L431RCT6 datasheet (accessed 2026-08-19).

How Do You Read the STM32L431RCT6 Pinout for a 64-LQFP Board?

The STM32L431RCT6 uses a 64-pin LQFP package. The XAIPART database pinout table lists the following verified pin functions. Always cross-check against the official datasheet before starting your PCB layout.

Design note: the database pinout lists two groups of PB8/PB9 CAN pins and VSS/VDD pins (pins 45-48 and 59-62). Confirm your netlist against the official STMicroelectronics datasheet before production.

How Do You Design a Battery-Powered IoT Sensor Node with STM32L431RCT6?

Start with the STM32L431RCT6 as the main MCU. Its 1.71V to 3.6V operating voltage range lets you power the design directly from 2x AA cells or a single Li-ion cell. The verified Standby-with-RTC current of 3.4 uA and Shutdown current of 100 nA let the node sleep for most of its life.

Follow these verified design rules from the product description:

• Place a 100 nF capacitor on each power pin.
• Place a 4.7 uF capacitor on the main supply.
• Connect VDDA to a clean analog supply to minimize noise for the 12-bit ADC and 12-bit DAC.
• Bring out SWDIO (PA13) and SWCLK (PA14) for programming and debugging.
• Use BOOT0 (pin 44) for boot-mode selection.

For a typical duty-cycled node, keep the MCU in Standby with RTC between readings, wake on an RTC event, sample sensors with the 12-bit ADC, process data on the 80 MHz Cortex-M4 core, and transmit over USART, SPI, I2C, or a radio module. The 256 KB Flash stores firmware and data logs; the 64 KB SRAM supports the protocol stack and sensor fusion buffers.

Battery life calculation using verified data: with a [VERIFY_NEEDED: assumed 500 mAh battery capacity] and the verified 3.4 uA Standby-with-RTC current, the idealized battery life is 500 mAh / 3.4 uA = 147,058 hours, or about 16.8 years. This is an upper-bound estimate that [VERIFY_NEEDED: ignores self-discharge, regulator losses, ADC sampling current, and radio transmission current]. In Shutdown mode, the verified 100 nA current extends the theoretical idle life even further, but wake-up events add energy consumption.

Result: the STM32L431RCT6 is suitable for multi-year battery-operated nodes because its lowest-power modes are in the nA-to-uA range and its supply range matches common battery chemistries.

Which Applications Are Best Suited for the STM32L431RCT6?

The XAIPART product database lists six primary application areas for the STM32L431RCT6.

STM32L431RCT6 vs STM32L431RBT6: Which MCU Should You Choose?

According to the verified FAQ, the STM32L431RCT6 and STM32L431RBT6 share the same package and pinout, but the Flash memory size is different.

Other alternatives in the database include the STM32L431RCT6TR (same device, tape-and-reel packaging), the STM32L431CCU6 (different package, 48-pin, 256 KB Flash), the GD32F303RCT6 (cross-brand, Cortex-M4 core, different peripherals), and the APM32F407RCT6 (cross-brand, Cortex-M4 core, 256 KB Flash). Verify pin compatibility and electrical characteristics before substituting any cross-brand part.

What Is the Cost of STM32L431RCT6 in 2026?

The verified XAIPART pricing tiers, as of 2026-08-19, are shown below. The base price is $3.10 and the minimum order quantity is 1.

XAIPART lists 99,999 units in stock with a MOQ of 1, indicating immediate availability for prototyping and production.

Where Can You Buy STM32L431RCT6 and Get the Datasheet?

You can buy the STM32L431RCT6 from the XAIPART STM32L431RCT6 product page. The official datasheet is available from STMicroelectronics at https://www.st.com/resource/en/datasheet/stm32l431rc.pdf (accessed 2026-08-19). Always purchase from authorized distributor channels to guarantee authenticity and traceability.

Conclusion

The STM32L431RCT6 combines an 80 MHz Arm Cortex-M4 core with FPU, 256 KB Flash, 64 KB SRAM, a 12-bit ADC with up to 16 channels, a 12-bit DAC with 2 channels, and multiple low-power modes in a 64-pin LQFP package. With verified Standby-with-RTC current of 3.4 uA and Shutdown current of 100 nA, it is a strong choice for industrial sensors, smart meters, portable medical devices, IoT nodes, audio processing, and motor control. Use the pinout and design notes in this guide to start your STM32L431RCT6 schematic and PCB layout with confidence.