STMicroelectronics STM32L151R8T6

Overview

STM32L151R8T6 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 STM32L151R8T6 datasheet, STM32L151R8T6 pinout, STM32L151R8T6 application, or STM32L151R8T6 equivalent, key selection criteria include verified ultra-low-power mode current (0.28 µA Standby), USB 2.0 full-speed interface with internal 48 MHz PLL, LCD driver exclusion (confirmed for R8-A variant), and LQFP64 package compatibility with industrial temperature range (-40°C to +105°C).

Technical Context

The device implements a tightly integrated ultra-low-power architecture with five low-power modes (Run, Sleep, Low-power Run, Stop, Standby), dynamic voltage scaling, and multiple clock sources including HSE (1–24 MHz), LSE (32.768 kHz RTC), HSI (16 MHz ±1%), and MSI (65 kHz–4.2 MHz). Its memory protection unit (MPU) enforces privilege separation between secure and non-secure code execution.

Analog subsystem includes two ultra-low-power comparators with window mode and wake-up capability, temperature sensor, VREFINT reference, and hardware-accelerated capacitive sensing (up to 20 channels). The USB peripheral uses an internal PLL and supports full-speed (12 Mbps) operation without external crystal.

Key Specifications

Pinout & Package

LQFP64 (10 × 10 mm, 0.5 mm pitch) package with exposed thermal pad - optimized for thermal dissipation in compact industrial modules and wearable form factors.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STM32L151R8T6, STM32L071RBT6 trades USB and EEPROM for lower gate count and cost, while STM32L431RBT6 upgrades to M4F with FPU and larger memory at higher active power - making the L151 optimal for USB-enabled, EEPROM-dependent, sub-µA standby applications.

Availability

STM32L151R8T6 is available at Aetrix Electronics and suitable for battery-powered IoT sensors, portable medical monitors, and smart utility meters requiring stable component supply across extended product lifecycles.

Supply support for STM32L151R8T6 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 STM32L1 series targets ultra-low-power embedded applications where energy efficiency, memory reliability, and analog integration are critical - especially in battery-constrained, long-lifecycle industrial and medical devices.

FAQ

Does STM32L151R8T6 include an integrated LCD controller?

No. The STM32L151R8T6 (R8-A suffix) explicitly excludes the LCD controller, as confirmed in ST's device summary table and Section 3.9 of the datasheet. Only STM32L152x6/8/B-A variants include the 8×40 segment LCD driver with on-board step-up converter and contrast adjustment.

What is the maximum operating frequency with guaranteed timing at 1.8 V supply?

At 1.8 V supply, the maximum guaranteed CPU frequency is 16 MHz, per Table 4 (CPU frequency range depending on dynamic voltage scaling) and Section 6.3.1. This is enforced by the DVS (Dynamic Voltage Scaling) controller to maintain timing margins under low-voltage conditions.

Can the internal 16 MHz HSI RC oscillator be used directly for USB clock generation?

No. USB full-speed operation requires a precise 48 MHz clock with ±0.25% tolerance. The HSI is factory-trimmed to ±1%, so it must be fed into the internal PLL (with 3× multiplication) to generate the required 48 MHz USB clock - as specified in Section 3.4 and Table 34 (PLL characteristics).

How many I/O pins support 5V tolerance, and are they configurable per-pin?

73 of the 83 fast I/Os are 5V tolerant, as stated in the "Features" section and confirmed in Section 3.6. Tolerance is inherent to the I/O structure and cannot be disabled or configured per-pin - all pins in the 5V-tolerant groups (PA–PD) retain this capability regardless of alternate function assignment.