STMicroelectronics STM32L081CBT6

Overview

STM32L081CBT6 from STMicroelectronics is an ultra-low-power 32-bit Arm® Cortex®-M0+ microcontroller with 192 KB Flash, 20 KB SRAM, and 6 KB EEPROM with ECC; features 12-bit ADC (1.14 Msps), AES-128 hardware encryption, and operates from 1.65–3.6 V across –40 to +125 °C for battery-powered industrial sensors and smart metering endpoints.

For engineers reviewing the STM32L081CBT6 datasheet, STM32L081CBT6 pinout, STM32L081CBT6 application, or STM32L081CBT6 equivalent, key selection criteria include standby current (0.29 µA), RTC-enabled stop mode (0.86 µA), 5 µs Flash wakeup, 31 5V-tolerant I/Os, and integrated AES for secure firmware updates in constrained-edge devices.

Technical Context

The STM32L081CBT6 implements a dual-bank Flash architecture with read-while-write capability and ECC protection, enabling safe over-the-air updates without halting execution. Its clock system integrates six independent sources-including factory-trimmed 16 MHz HSI (±1%), 32 kHz LSE for RTC calibration, and programmable MSI (65 kHz–4.2 MHz)-managed via a configurable clock tree supporting dynamic voltage scaling.

Low-power operation is enforced by five hierarchical modes: Run, Sleep, Low-power Run, Stop, and Standby-each with distinct peripheral availability and retention options. The device supports wake-up from Stop mode via 16 lines or from Standby via three dedicated pins, with hardware-accelerated AES and CRC units operating independently of CPU state.

Key Specifications

Pinout & Package

LQFP48 package (7 × 7 mm, 0.5 mm pitch), RoHS-compliant and ECOPACK2 certified. Pinout validated per STMicroelectronics DS10888 Rev 6, Figure 3 and Table 14.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STM32L071CBT6, the L081 offers 64 KB additional Flash and AES for secure boot; versus STM32L431CBT6, it trades computational headroom for superior sub-µA standby efficiency and smaller footprint-critical for disposable or sealed battery applications.

Availability

STM32L081CBT6 is available at Aetrix Electronics and suitable for smart utility metering, wireless sensor nodes, medical wearable patches, and asset tracking beacons requiring stable component supply and long-term lifecycle assurance.

Supply support for STM32L081CBT6 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 analog products for industrial, automotive, and consumer markets.

The STM32L0 series targets ultra-low-power embedded applications demanding multi-year battery life, secure firmware execution, and rich analog integration-optimized for IoT edge nodes, portable medical devices, and energy-harvesting systems.

FAQ

What is the maximum operating frequency and core type of the STM32L081CBT6?

The STM32L081CBT6 uses an Arm Cortex-M0+ core rated for up to 32 MHz operation. It delivers 0.95 DMIPS per MHz and includes a Memory Protection Unit (MPU) for enhanced system reliability. Frequency scaling is supported via dynamic voltage scaling, allowing the core to run at lower voltages when reduced performance is acceptable-key for extending battery life in intermittent-use applications.

Does the STM32L081CBT6 support hardware AES encryption, and how is it implemented?

Yes, the STM32L081CBT6 integrates a dedicated hardware AES-128 engine compliant with FIPS-197. It supports ECB, CBC, CTR, and GCM modes with DMA co-processing, enabling encrypted data transfers without CPU intervention. The engine operates independently in all low-power modes except Standby, and keys can be stored in protected memory or derived from unique 96-bit device ID for secure key binding.

How many I/O pins are 5V tolerant, and what is their voltage rating?

31 of the 40 general-purpose I/Os on the STM32L081CBT6 are 5V tolerant, meaning they safely accept input voltages up to 5.5 V regardless of VDD level (1.65–3.6 V). This eliminates external level-shifting circuitry when interfacing with legacy 5V peripherals such as RS-232 transceivers, industrial sensors, or discrete logic-reducing BOM cost and PCB area in mixed-voltage systems.

What RTC accuracy can be achieved, and is calibration supported?

The integrated RTC uses a dedicated 32.768 kHz LSE oscillator with hardware calibration capability, achieving ±1 ppm accuracy over –40 to +85 °C when paired with a temperature-compensated crystal. Calibration values are stored in backup registers and can be adjusted in firmware via the RTC_CALR register; the device also supports automatic calibration against the HSE clock for improved long-term stability without external components.