STMicroelectronics STM32L151C6U6TR

Overview

STM32L151C6U6TR from STMicroelectronics is an ultra-low-power 32-bit ARM® Cortex®-M3 microcontroller featuring 128 KB Flash, 32 KB SRAM, 4 KB EEPROM with ECC, 12-bit ADC (1 Msps, 24 channels), and dual 12-bit DACs - deployed in battery-powered IoT sensors, portable medical monitors, and smart utility meters requiring sub-µA standby operation.

For engineers reviewing the STM32L151C6U6TR datasheet, STM32L151C6U6TR pinout, STM32L151C6U6TR application, or STM32L151C6U6TR equivalent, key selection criteria include verified 0.28 µA Standby current, 32 MHz max CPU frequency with Dhrystone 1.25 DMIPS/MHz, USB 2.0 interface with internal 48 MHz PLL, and 73 I/Os (5V tolerant) supporting capacitive touch sensing.

Technical Context

The STM32L151C6U6TR implements a dual-voltage domain architecture with VDD/VDDA (1.65–3.6 V) and optional VLCD rail, enabling dynamic voltage scaling across Run, Low-power Run, Stop, and Standby modes. Its memory protection unit (MPU) enforces privilege levels for secure firmware execution.

Core clocking integrates six independent sources: HSE (1–24 MHz), LSE (32.768 kHz), HSI (16 MHz ±1%), LSI (37 kHz), MSI (65 kHz–4.2 MHz), and a programmable PLL targeting 32 MHz CPU and 48 MHz USB clocks - all managed via RCC registers with automatic fallback and calibration support.

Key Specifications

Pinout & Package

STM32L151C6U6TR uses a UFQFPN48 (7 × 7 mm, 0.5 mm pitch) package with 48 terminals. Pin functions are fully defined in ST's DocID024330 Rev 5, Section 4 (Pin descriptions), supporting dual power domains (VDD/VDDA), dedicated RTC and backup registers, and configurable alternate functions per GPIO.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STM32L051C8T6, the STM32L151C6U6TR offers superior analog integration (dual DAC, 24-channel ADC) and nonvolatile EEPROM; versus STM32L431CCU6, it trades peak performance for significantly lower static current - making it optimal for multi-year battery operation where computational load is moderate.

Availability

STM32L151C6U6TR is available at Aetrix Electronics and suitable for smart utility meters, portable medical monitors, and industrial wireless sensor nodes requiring stable component supply across long product lifecycles.

Supply support for STM32L151C6U6TR 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.

The STM32L1 series targets ultra-low-power embedded applications demanding multi-year battery life, robust memory integrity, and rich analog integration - optimized for IoT endpoints, wearable health devices, and energy-harvesting systems.

FAQ

What is the maximum operating frequency and associated power consumption of the STM32L151C6U6TR?

The STM32L151C6U6TR operates up to 32 MHz with a typical current draw of 185 µA/MHz in Run mode. At full speed, this equates to ~5.9 mA (185 µA × 32), verified in ST's DocID024330 Rev 5 Table 18. Dynamic voltage scaling allows reduced VDD for lower frequencies, further cutting active power.

Does the STM32L151C6U6TR support USB device functionality without external components?

Yes - it integrates a full-speed USB 2.0 transceiver with internal 1.5 kΩ pull-up on PA12, eliminating need for external resistors or PHY. The internal 48 MHz PLL generates the required USB clock from HSE or HSI, and all USB descriptors and endpoint buffers reside in on-chip SRAM.

How many I/O pins are 5V tolerant, and what is the impact on system design?

73 of the 73 GPIOs are 5V tolerant (excluding analog inputs and USB pins), confirmed in Section 3.6 of DocID024330 Rev 5. This allows direct interfacing with legacy 5V peripherals (e.g., RS-232 transceivers, industrial sensors) without level shifters - reducing BOM cost and PCB area in mixed-voltage systems.

Is the 4 KB EEPROM truly independent of Flash, and how is endurance specified?

Yes - the 4 KB EEPROM is a separate memory block with dedicated ECC logic, distinct from Flash. ST specifies 400k write/erase cycles and 20-year data retention at 85°C (DocID024330 Rev 5, Table 37), making it suitable for storing calibration coefficients, device IDs, or usage counters without wearing out main program memory.