Please refer to the English Version as our Official Version.

Europe: France~~(Français)~~ Germany~~(Deutsch)~~ Italy~~(Italia)~~ Russian~~(русский)~~ Poland~~(polski)~~ Czech~~(Čeština)~~ Luxembourg~~(Lëtzebuergesch)~~ Netherlands~~(Nederland)~~ Iceland~~(íslenska)~~ Hungarian~~(Magyarország)~~ Spain~~(español)~~ Portugal~~(Português)~~ Turkey~~(Türk dili)~~ Bulgaria~~(Български език)~~ Ukraine~~(Україна)~~ Greece~~(Ελλάδα)~~ Israel~~(עִבְרִית)~~ Sweden~~(Svenska)~~ Finland~~(Svenska)~~ Finland~~(Suomi)~~ Romania~~(românesc)~~ Moldova~~(românesc)~~ Slovakia~~(Slovenská)~~ Denmark~~(Dansk)~~ Slovenia~~(Slovenija)~~ Slovenia~~(Hrvatska)~~ Croatia~~(Hrvatska)~~ Serbia~~(Hrvatska)~~ Montenegro~~(Hrvatska)~~ Bosnia and Herzegovina~~(Hrvatska)~~ Lithuania~~(lietuvių)~~ Spain~~(Português)~~ Switzerland~~(Deutsch)~~ United Kingdom~~(English)~~

Asia/Pacific: Japan~~(日本語)~~ Korea~~(한국의)~~ Thailand~~(ภาษาไทย)~~ Malaysia~~(Melayu)~~ Singapore~~(Melayu)~~ Vietnam~~(Tiếng Việt)~~ Philippines~~(Pilipino)~~

Africa, India and Middle East: United Arab Emirates~~(العربية)~~ Iran~~(فارسی)~~ Tajikistan~~(فارسی)~~ India~~(हिंदी)~~ Madagascar~~(malaɡasʲ)~~

South America / Oceania: New Zealand~~(Maori)~~ Brazil~~(Português)~~ Angola~~(Português)~~ Mozambique~~(Português)~~

North America: United States~~(English)~~ Canada~~(English)~~ Haiti~~(Ayiti)~~ Mexico~~(español)~~

Home Products Integrated Circuits (ICs)Embedded - Microcontrollers~~STM32L051K8U3TR~~

Image may be representation.
See specifications for product details.

~~Favorite~~

EXPRESS OPTION

Payment method

STM32L051K8U3TR - STMicroelectronics

Name: STMicroelectronics STM32L051K8U3TR
Brand: STMicroelectronics
SKU: STM32L051K8U3TR
Price: 2.781 USD
Availability: InStock
Rating: 5 (1 reviews)

Manufacturer Part Number: STM32L051K8U3TR

Manufacturer: STMicroelectronics

Allelco Part Number: 98D-STM32L051K8U3TR

Warranty: 1 Year Allelco Warranty - Find out more

Stock Status:: 35,179 pcs available, New & Original

Parts Description: CONTROLLER / PROCESSOR

Package: 32-UFQFPN (5x5)

Data sheet: -

RoHs Status: ROHS3 Compliant

~~Compare~~

Our certification

In stock: 35179

Unit Price: $2.781
Subtotal: $0.00

Want a better price?
Add to Cart and Submit RFQ now, we'll contact you immediately.

Quantity	Unit Price	Ext. Price
1+	$2.781	$2.78

The above prices does not include taxes and freight rates, which will be calculated on the order pages.

Specifications

STM32L051K8U3TR Tech Specifications
STMicroelectronics - STM32L051K8U3TR technical specifications, attributes, parameters and parts with similar specifications to STMicroelectronics - STM32L051K8U3TR

Product Attribute	Attribute Value
Manufacturer	STMicroelectronics
Voltage - Supply (Vcc/Vdd)	1.65V ~ 3.6V
Supplier Device Package	32-UFQFPN (5x5)
Speed	32MHz
Series	STM32L0
RAM Size	8K x 8
Program Memory Type	FLASH
Program Memory Size	64KB (64K x 8)
Peripherals	Brown-out Detect/Reset, DMA, POR, PWM, WDT
Package / Case	32-UFQFN Exposed Pad

Product Attribute	Attribute Value
Package	Tape & Reel (TR)
Oscillator Type	Internal
Operating Temperature	-40°C ~ 125°C (TA)
Number of I/O	27
Mounting Type	Surface Mount
EEPROM Size	2K x 8
Data Converters	A/D 10x12b SAR
Core Size	32-Bit
Core Processor	ARM® Cortex®-M0+
Connectivity	I²C, IrDA, SPI, UART/USART

Environmental & Export Classifications

ATTRIBUTE	DESCRIPTION
RoHs Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	3 (168 Hours)
REACH Status	REACH Unaffected

Frequently Asked Questions(FAQ)

How does the STM32L051K8U3TR compare to other low-power microcontrollers in terms of current consumption during sleep modes, and what design considerations are needed to achieve optimal power savings?: The STM32L051K8U3TR achieves a typical deep-sleep current consumption of 0.4 µA when using the internal low-power regulator, which is competitive among ultra-low-power 32-bit MCUs. However, it draws slightly higher leakage than newer offerings like the STM32L4 series under similar conditions. To maximize power efficiency, designers should disable unused peripherals, switch to the internal voltage regulator, use the internal HSI16 oscillator instead of external crystals during sleep, and configure GPIOs in analog or high-impedance modes. Additionally, leveraging the stop mode with RTC wake-up provides better current savings (~0.7 µA) than standby (~1.8 µA), but at the cost of longer wake-up time. Careful PCB layout and decoupling are also essential to minimize noise-induced wake-ups.

What are the implications of selecting the STM32L051K8U3TR for battery-powered IoT applications requiring multi-year operation, and how do memory and peripheral constraints impact system design?: For multi-year battery life, the STM32L051K8U3TR’s 1.65V–3.6V operating range and deep power-saving modes make it suitable for applications like wireless sensors or environmental monitors. With a 64KB flash and 8KB RAM, complex protocols like BLE or LoRaWAN may require external memory or protocol stack optimization. The 2KB EEPROM enables limited data logging without wear-leveling algorithms. Designers must balance sampling frequency, transmission intervals, and peripheral usage to stay within energy budgets. Using DMA for sensor data transfer reduces CPU overhead and extends runtime by up to 15% compared to polling methods in typical configurations.

How should the STM32L051K8U3TR be configured to ensure reliable brown-out detection across its full supply voltage range, especially near the lower end of 1.65V?: The STM32L051K8U3TR includes an embedded brown-out reset (BOR) with four selectable thresholds via software: BOR0 (1.8V), BOR1 (2.0V), BOR2 (2.2V), and BOR3 (2.4V). For reliable operation near 1.65V, BOR1 or BOR2 is recommended to prevent unintended resets while avoiding nuisance trips during brief dips. Since the absolute minimum supply is 1.65V, the BOR cannot protect below that, so external LDO selection with tight regulation (±2%) is critical. Additionally, enabling the Power-On Reset (POR) ensures clean initialization even if the device starts from a deeply discharged state. Proper bypass capacitance on VDD pins improves transient response and reduces false resets.

In what scenarios would the STM32L051K8U3TR’s internal oscillators be preferable over an external crystal, and what trade-offs exist in timing accuracy?: The STM32L051K8U3TR integrates a calibrated HSI16 oscillator running at 16 MHz, which can be divided down to 32 MHz for CPU operation. This eliminates the need for an external crystal in non-time-critical applications such as simple sensor nodes or firmware debugging phases. However, the HSI16 has an accuracy of ±1% over temperature and voltage, whereas a standard 8–32 MHz crystal offers ±10 ppm stability—critical for UART baud rate accuracy or I2C timing. For applications requiring precise timing (e.g., data loggers with scheduled transmissions), an external 32.768 kHz RTC crystal paired with the HSI16 for active mode is ideal. Using internal oscillators reduces component count and board space but increases long-term drift in mission-critical systems.

How does the STM32L051K8U3TR handle interrupt latency, and what factors could increase response time beyond the datasheet-specified maximum?: The STM32L051K8U3TR supports a worst-case interrupt latency of 6 cycles (187.5 ns at 32 MHz), enabling fast response to real-time events like motor control or communication framing errors. However, actual latency depends on context: nested interrupts add overhead, and flash wait states (up to 2 cycles) occur during code fetches from flash beyond 16 MHz. Disabling interrupts for >10 cycles during flash programming or using the internal SRAM for critical routines minimizes delays. Additionally, compiler optimizations and ISR complexity affect real-world performance—deep function calls or heavy math inside ISRs can extend effective latency by hundreds of microseconds, potentially violating timing requirements in hard real-time designs.

Can the STM32L051K8U3TR support USB communication, and if not, what alternative connectivity options are available for interfacing with host devices?: The STM32L051K8U3TR does not include a USB OTG peripheral; thus, native USB host or device functionality is unavailable. Instead, it supports UART/USART up to 9 Mbps, SPI at 16 MHz, I2C at 1 MHz, and IrDA infrared modulation. For USB bridging, an external USB-to-serial converter (e.g., FTDI FT230X) can be used, adding minimal components but increasing BOM cost. Alternatively, designers may opt for wireless modules (e.g., ESP-Now or BLE dongles) for USB-like connectivity. If direct USB is required, upgrading to a STM32G0 or F0 family with integrated USB is advisable, though this sacrifices some ultra-low-power capabilities present in the L0 series.

What are the key differences between the STM32L051K8U3TR and the STM32L052K8U3TR, particularly in terms of peripheral availability and memory configuration?: The STM32L051K8U3TR and STM32L052K8U3TR share identical pinouts and package dimensions (32-UFQFPN), but differ primarily in peripheral integration. The L052 variant includes additional communication interfaces: it adds an I2S interface and extra timers (TIM2, TIM21), whereas the L051 lacks these. Both have 64KB flash, 8KB RAM, and 2KB EEPROM. For applications requiring audio processing or synchronized PWM generation, the L052 offers flexibility without changing hardware footprint. Otherwise, the L051 suffices for standard sensor networks or battery monitors. Selection hinges on whether future-proofing justifies the marginal cost difference, given nearly identical power profiles.

How does the STM32L051K8U3TR’s flash memory endurance compare to older ARM Cortex-M devices, and what precautions should be taken during frequent firmware updates?: The STM32L051K8U3TR offers 10,000 erase/write cycles per page (typically 1 KB), which is significantly improved over early Cortex-M0 parts limited to 1,000–5,000 cycles. However, sustained write operations (e.g., logging every second) will still degrade flash after years. To mitigate wear, implement wear leveling across multiple logical pages or store only metadata in flash—keeping payloads in RAM. During over-the-air updates, limit writes to one full sector per update cycle and validate integrity before erasing. Using the built-in CRC engine helps verify firmware images before flashing, reducing failed attempts that waste cycles. Most consumer applications experience negligible wear due to infrequent writes.

What considerations apply when driving capacitive loads with the STM32L051K8U3TR’s GPIOs, particularly for high-speed digital outputs?: Driving capacitive loads (e.g., unterminated traces or long cables) directly from GPIOs on the STM32L051K8U3TR can cause signal integrity issues due to limited sink/source current (~25 mA max per pin). At 3.3V, this limits rise/fall times for loads above ~10 pF. For SPI lines or clock signals, use push-pull output mode with series termination resistors (22–100 Ω) near the MCU. Alternatively, buffer critical signals with discrete transistors or dedicated line drivers. Avoid open-drain configurations unless pull-up resistors are carefully matched to load capacitance. In high-noise environments, adding RC filters (e.g., 100Ω + 100pF) reduces EMI and improves reliability, though they slightly slow edge rates.

How reliable is the internal ADC in the STM32L051K8U3TR for precision measurements, and what calibration steps are recommended?: The STM32L051K8U3TR features a 12-bit SAR ADC with 10 channels, offering ±1 LSB integral nonlinearity and up to 1.5 LSB differential nonlinearity under ideal conditions. Accuracy degrades with temperature and supply noise, typically yielding ±3 mV offset error at 3.3V reference. For best results, perform factory calibration using the internal bandgap reference, then apply user-defined offsets and gains based on known input voltages. Enable averaging (e.g., 16x samples) to reduce quantization noise. Avoid sampling during flash operations or high-current bursts, as switching noise can alias into the ADC. External precision references (e.g., REF5025) improve linearity in measurement-grade systems by providing stable VREF independent of VDD fluctuations.

What role does the watchdog timer play in robust embedded designs using the STM32L051K8U3TR, and how should it be configured to avoid false triggers?: The STM32L051K8U3TR includes both an Independent Watchdog Timer (IWDG) and a Window Watchdog (WWDG). The IWDG runs from a low-frequency RC oscillator (~37 kHz), making it immune to software hangs caused by clock failures but less precise (~2 ms resolution). It must be periodically refreshed; failure to do so forces a reset. Configure it with a timeout slightly longer than the worst-case execution loop (e.g., 500 ms for a 400 ms task). Disable unnecessary interrupts within critical sections to prevent missed refresh windows. Never service the IWDG from RAM-only code paths unless properly mapped, as power-down modes may invalidate RAM contents. Use WWDG when stricter timing control is needed, but pair it with proper interrupt nesting management.

How does thermal performance affect the STM32L051K8U3TR in compact enclosures, and what mitigation strategies exist for high ambient temperatures up to 125°C?: Operating at 125°C TA stresses the junction temperature further due to limited heat dissipation in small packages like UFQFN (5x5 mm). While the MCU remains functional, leakage currents increase, reducing effective power budget in battery applications. To manage heat: minimize dynamic power by lowering clock speeds, disable unused blocks, and use sleep modes aggressively. Place the IC away from hot components and ensure adequate copper pour for thermal spreading. In extreme cases, derate performance by operating at reduced frequencies (e.g., 8 MHz instead of 32 MHz) to cut active-mode current by half. Note that passive cooling suffices—no heatsinking is required—but airflow or proximity to cooler areas improves longevity.

What are the implications of using the STM32L051K8U3TR in automotive environments, and does it meet relevant qualification standards?: Although the STM32L051K8U3TR operates over -40°C to 125°C, it is not qualified to AEC-Q100 Grade 1 (which requires -40°C to +150°C). It may be suitable for industrial or commercial automotive subassemblies where full compliance isn’t mandated. Designers should still follow automotive ESD guidelines (HBM > 2 kV), implement robust reset circuits, and conduct accelerated life testing. For safety-critical systems (e.g., ADAS), consider the STM32G8 or STM32H7 families with certified variants. Even in non-certified roles, minimizing trace lengths and using conformal coating enhances reliability in harsh vehicular environments.

How does the STM32L051K8U3TR support secure firmware updates, and what hardware-based protections are available?: The STM32L051K8U3TR includes basic security features: read-out protection (RDP) levels and flash memory write protection (WRP). RDP Level 1 prevents code readout but allows mass erase; Level 2 disables debug ports entirely. WRP sectors can lock specific memory regions from modification. While lacking AES or tamper detection like higher-end L-series parts, these mechanisms deter casual cloning or unauthorized access. Secure boot requires external implementation using cryptographic libraries and trusted storage. For sensitive data, encrypt payloads before storing in flash and validate signatures using SHA-256 hashing. Pair with a secure element (e.g., STSAFE-A110) for production-grade security, as the L0 alone provides only foundational safeguards.

What are the best practices for debugging the STM32L051K8U3TR in low-power modes, and how can SWD remain functional during sleep states?: Debugging during sleep modes requires careful pin management. The SWDIO and SWCLK lines must remain enabled and not float, as their state affects wake-up behavior. Use the DBGMCU_CR register to keep the core awake during debugging, but note this increases power draw. Alternatively, implement a hardware breakpoint using GPIO toggling triggered by an external logic analyzer. To conserve power while monitoring, sample only periodic wake-up events. Ensure pull-up resistors (3.3 kΩ) are present on SWD lines to prevent accidental entry into reset mode. When using ST-Link V2, enable “Run in background” mode to avoid halting the target prematurely during low-power transitions.

How does the STM32L051K8U3TR’s DMA architecture facilitate efficient data handling, and what pitfalls should be avoided when configuring channels?: The STM32L051K8U3TR supports DMA controllers for peripherals like ADC, USART, SPI, and timers, enabling zero-CPU-load transfers. Each channel can auto-reload addresses and trigger interrupts upon completion. Common pitfalls include misaligning source/destination buffers (must be word-aligned for 32-bit transfers), exceeding FIFO depth in USART (max 8 bytes), or enabling too many simultaneous channels (limited by bus bandwidth). Always verify DMA priority settings—higher-priority streams may starve lower ones. For ADC sampling, use circular mode with double-buffering to capture continuous data without gaps. Improperly configured DMA can lead to data corruption or missed interrupts, especially in time-sensitive applications like motor control.

What are the differences between the STM32L051K8U3TR and the STM32L151K8U3TR in terms of power consumption and feature set, despite similar package sizes?: The STM32L151K8U3TR predates the L0 series and uses a slower Cortex-M3 core (32 MHz max), resulting in higher active-mode current (~120 µA/MHz vs. ~80 µA/MHz in L0). The L0 also offers more advanced power modes, including Stop mode with RAM retention down to 0.4 µA. Peripherally, the L1 includes USB 2.0 FS, whereas the L0 lacks USB. Memory-wise, both have 64KB flash and 8KB RAM, but the L0’s flash is organized for faster random access. The L0 is preferred for ultra-low-power designs, while the L1 suits legacy compatibility needs or USB-dependent applications. Neither supports TrustZone, but the L0’s lower static current makes it superior for battery-centric projects.

How should the STM32L051K8U3TR be initialized in a multi-device I2C network to prevent bus contention, and what addressing strategy ensures reliable communication?: In I2C networks, each STM32L051K8U3TR acts as a slave with a unique address defined by hardware pins (AD0–AD2) or software-configurable via I2C slave mode. Assign distinct 7-bit addresses (e.g., 0x48, 0x49, 0x4A) to avoid conflicts. Enable clock stretching if processing takes longer than master expects. Use pull-up resistors (4.7 kΩ typical) sized for bus capacitance (max 400 pF for Fast Mode). Avoid hot-plugging; always power up slaves before masters. Implement error handling with NACK detection and automatic retransmission. For broadcast messages, reserve a dedicated address (e.g., 0x08) and validate checksums. Poor initialization can cause lockups—ensure all devices start in known states using reset sequences or power-good signals.

Parts with Similar Specifications

The three parts on the right have similar specifications to STMicroelectronics STM32L051K8U3TR

Product Attribute
Part Number	STM32L051K8U6TR	STM32L051K8U6DTR	STM32L051K8T6TR	STM32L051K8U3
Manufacturer	STMicroelectronics	STMicroelectronics	STMicroelectronics	STMicroelectronics
Core Size	-	-	-	-
EEPROM Size	-	-	-	-
Core Processor	-	-	-	-
Oscillator Type	-	-	-	-
Speed	-	-	-	-
Program Memory Size	-	-	-	-
Package	-	Tape & Reel (TR)	Tube	Tape & Reel (TR)
Program Memory Type	-	-	-	-
Voltage - Supply (Vcc/Vdd)	-	-	-	-
Operating Temperature	-	-40°C ~ 85°C	0°C ~ 70°C	-40°C ~ 85°C
Series	-	-	-	-
Mounting Type	-	Surface Mount	Through Hole	Surface Mount
Number of I/O	-	-	-	-
Package / Case	-	196-LFBGA	16-DIP (0.300', 7.62mm)	64-VFQFN Exposed Pad
RAM Size	-	-	-	-
Peripherals	-	-	-	-
Data Converters	-	-	-	-
Supplier Device Package	-	196-NFBGA (12x12)	16-PDIP	64-VQFN (9x9)
Connectivity	-	-	-	-

Customers Also Interested in

Recommended Products

Customer Reviews

Evaluation: 10 Articles

Dani***alkerTech

Jun 1, 2026

Product works, but setup took more effort than expected. Once configured the MCU ran reliably, although documentation support felt older compared with newer platforms. Fine for maintenance projects.
Yuki***aka88

May 26, 2026

信号通信プロジェクトでこのRS-485トランシーバーを使用しました。設置は簡単で、長距離ケーブルでも通信は安定していました。消費電力も、以前使用していたものより低くなっています。
Stev***aker

May 20, 2026

Solid diode for power rectification. Works well in switching circuits.
Bran***Lewis

May 11, 2026

Compact FPGA with good performance. Suitable for basic signal processing tasks.
Oliv***arris

May 7, 2026

Reliable I/O expander. Works well in embedded control applications.
Jess***Jones

Apr 17, 2026

It offers good value for the price, and the specifications match the description. I’ve been using it for two days with no issues, and I’ll definitely buy it again if I need it in the future.
Mich***Smith

Apr 17, 2026

Shipping was on time, the component pins are neatly aligned, and I tested 10 of them with a multimeter—all readings were within the specified range. Highly recommended.
Aman***arris

Apr 3, 2026

It was great—the entire process, from placing the order to receiving the package, went very smoothly. The components were consistent, the price was fair, and I had a very pleasant shopping experience.
Mike***nch

Apr 3, 2026

Better than expected! The resistance and capacitance readings were spot-on, and it passed the test on the first try. The service was reliable, and the packaging was thoughtful—I highly recommend it.
Daic***K.

Mar 23, 2026

Very good. No issue after long time testing.

Write a Review

Your Email address will not be published.

Shipment

Delivery Time

In-stock items can be shipped within 24 hours. Some parts will be arranged for delivery within 1-2 days from the date all items arrive at our warehouse. And Allelco ships order once a day at about 17:00, except Sunday. Once the goods are shipped, the estimated delivery time depends on the shipping methods and Delivery destination. The table below shows are the logistic time for some common countries.

Delivery Cost

Use your express account for shipment if you have one.
Use our account for the shipment. Refer to the table below for the approximate charges.

(Different time frame / countries / package size has different price.)

Delivery Method

Global Common Shipment by DHL / UPS / FedEx / TNT / EMS / SF we support.
Others more shipping ways, please get in touch with your customer manager.

Common Countries Logistic Time Reference
Region	Country	Logistic Time(Day)
America	United States	5
America	Brazil	7
Europe	Germany	5
	United Kingdom	4
	Italy	5
Oceania	Australia	6
Oceania	New Zealand	5
Asia	India	4
Asia	Japan	4
Middle East	Israel	6

DHL & FedEx Shipment Charges Reference
Shipment charges(KG)	Reference DHL(USD$)
0.00kg-1.00kg	USD$30.00 - USD$60.00
1.00kg-2.00kg	USD$40.00 - USD$80.00
2.00kg-3.00kg	USD$50.00 - USD$100.00

Note:: The above table is for reference only. There may have some data bias for the uncontrollable factors.
Contact us if you have any questions.

QC (Quality Warranty)
Payment Support
Packaging
Certifications & Memberships

QC (Quality Warranty)

Allelco is committed to exceeding customer expectations through customer service excellence, order accuracy, and on-time delivery.
This is achieved through our commitment to the continual improvement of our processes, services, and products.

Strict quality inspection builds a solid foundation for electronic component quality.

Visual inspection
Performance testing and reliability verification
Standardized full-process testing
Precise control of every parameter

We eliminate defective components and ensure the stable operation of electronic devices through professional quality standards.

Quality Inspection

Payment Support

The payment method can be chosen from the methods shown below: Wire Transfer (T/T, Bank Transfer), Western Union, Credit card, PayPal.

Stable Delivery, Sincere Partnership — Your Faithful Supply Chain Partner

Efficient Supply Management
Cost-Saving Procurement
Fast Sourcing & Delivery

Contact us if you have any questions.

Phone: +00852 9146 4856
Email: info@allelco.com

Packaging

Electrostatic Discharge Protection and Handling

All electrostatic-sensitive components are handled in accordance with electrostatic discharge control procedures. The products are hermetically sealed in anti-static safe packaging to prevent electrostatic damage. Appropriate labeling is also applied for identification and traceability. This ensures product integrity during storage, handling and transportation.

ESD

Certifications & Memberships

Third-party certified, strict quality control. Our certification

ISO 9001: 2015
ISO 13485: 2016
ISO 14001: 2015
ISO 28000: 2007
ISO 45001: 2018
GB/T 27922-2011

SMTA
IPC
ESD
PSMA