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STMicroelectronics STM32L021F4U6TR
- Part No.:
- STM32L021F4U6TR
- Manufacturer:
- STMicroelectronics
- Category:
- Microcontrollers
- Package:
- 20-UFQFN
- Datasheet:
-
STM32L021F4U6TR.pdf
- Description:
- IC MCU 32BIT 16KB FLASH 20UFQFPN
- Quantity:
- Payment:
- Shipping:
Inventory:2,428
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Product details
Overview
STM32L021F4U6TR from STMicroelectronics is an ultra-low-power 32-bit Arm® Cortex®-M0+ microcontroller featuring 16 KB Flash, 2 KB SRAM, 512 B ECC-protected EEPROM, 12-bit ADC (1.14 Msps), and hardware AES-128 encryption. It operates from 1.65–3.6 V across –40 to +125 °C and delivers 76 µA/MHz in Run mode, targeting battery-powered sensor nodes and smart meters.
For engineers reviewing the STM32L021F4U6TR datasheet, STM32L021F4U6TR pinout, STM32L021F4U6TR application, or STM32L021F4U6TR equivalent, key selection criteria include standby current (0.23 µA), RTC-enabled Stop mode (0.54 µA with 2 KB RAM retention), 5V-tolerant I/O count (23 pins), and UFQFPN20 package compatibility for space-constrained designs.
Technical Context
The STM32L021F4U6TR integrates a Cortex-M0+ core running up to 32 MHz with dynamic voltage scaling, supported by multiple clock sources: 16 MHz factory-trimmed HSI (±1%), 32 kHz LSE for RTC calibration, and a 37 kHz LSI. Its low-power architecture enables five operational modes-Run, Sleep, Low-power Run, Stop, and Standby-with sub-µA retention states.
Analog subsystem includes a 10-channel 12-bit ADC (down to 1.65 V supply), two ultra-low-power comparators with window mode and wake-up capability, and internal temperature sensor/VREFINT. Communication is handled via USART (ISO 7816/IrDA), SPI (16 Mbit/s), I²C (SMBus/PMBus), and LPUART-all optimized for energy efficiency.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Core | Arm Cortex-M0+, 32 MHz max - deterministic real-time execution with 0.95 DMIPS/MHz performance density |
| Memory | 16 KB Flash (ECC), 2 KB SRAM, 512 B EEPROM (ECC) - robust firmware storage and data logging with error correction |
| Power Consumption | 0.23 µA Standby (2 wakeup pins), 0.54 µA Stop + RTC + 2 KB RAM - enables >10-year coin-cell operation in metering |
| ADC | 12-bit, 1.14 Msps, 10 channels, min. 1.65 V supply - supports high-resolution analog sensing without external regulators |
| Clock Sources | HSI16 (±1%), LSE (32 kHz RTC), MSI (65 kHz–4.2 MHz), PLL - flexible timing for precision RTC and variable-frequency peripherals |
| I/O Voltage Tolerance | 23 pins 5V tolerant - simplifies interface with legacy 5V logic and sensors without level shifters |
| Security | Hardware AES-128 engine - offloads encryption for secure OTA updates and sensor data confidentiality |
Pinout & Package
STM32L021F4U6TR uses the UFQFPN20 (3 × 3 mm, 0.5 mm pitch) package with 20 leads. This compact, leadless QFN exposes all essential power, reset, clock, debug, and peripheral I/O signals on a thermally enhanced footprint suitable for automated assembly and high-density PCB layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VDD, VSS | Power supply and ground | Dual VDD/VSS pairs ensure stable core and I/O rail decoupling; supports 1.65–3.6 V operation |
| NRST | Active-low reset input | Asynchronous reset with programmable PVD monitoring; compatible with external push-button or supervisor ICs |
| PA0–PA13, PB0–PB1 | General-purpose I/O | 23 total GPIOs (14 on PA, 2 on PB); 20 pins configurable as alternate functions including USART/SPI/I²C |
| PA14/PA15, PB6/PB7 | SWD debug interface | Serial Wire Debug (SW-DP) pins enable non-intrusive programming and real-time tracing with minimal pin overhead |
| OSC_IN/OSC_OUT | External high-speed clock input/output | Supports 0–32 MHz crystal or external clock source for precise timing-critical applications |
| LSE_IN/LSE_OUT | Low-speed external oscillator | Drives 32.768 kHz crystal for autonomous RTC operation with ±20 ppm accuracy over temperature |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low-power standby | 0.23 µA with two wakeup pins - extends shelf life and field deployment duration in always-on edge devices |
| RTC with RAM retention | 0.54 µA Stop mode + RTC + full 2 KB SRAM retention - maintains real-time context and sensor history during deep sleep |
| Pre-programmed bootloader | USART and SPI support - enables field firmware updates without JTAG/SWD hardware, reducing service cost |
| 5V-tolerant I/Os | 23 pins tolerate 5V inputs at 1.65–3.6 V VDD - eliminates level-shifter components in mixed-voltage systems |
| Hardware AES-128 | Dedicated cryptographic engine - accelerates encryption/decryption by >10× vs software-only, preserving CPU cycles for application logic |
Applications
| Smart Utility Metering | Wireless Sensor Node |
|---|---|
Use Scenario: Battery-powered gas/water meter with hourly pulse counting, temperature compensation, and encrypted data upload via NB-IoT. IC Role / Device Role / Timing Role: Main system controller managing ADC sampling, RTC-based scheduling, AES-encrypted payload generation, and low-power UART communication. Use Value: Sub-µA standby and RTC retention enable >15-year battery life; 5V-tolerant GPIOs interface directly with mechanical reed switches and Hall-effect sensors. | Use Scenario: Self-powered environmental monitor (temp/humidity/pressure) transmitting via BLE or LoRaWAN every 5 minutes. IC Role / Device Role / Timing Role: Central MCU coordinating sensor reads, data fusion, wake-up scheduling, and radio duty cycling using ultra-low-power timers. Use Value: 76 µA/MHz Run mode and 5 µs Flash wakeup minimize active time; integrated comparators trigger wake-on-event without CPU involvement. |
| Industrial Asset Tracker | Medical Wearable Patch |
Use Scenario: GPS-denied indoor asset tag reporting location via UWB or RSSI triangulation, logging motion events to EEPROM. IC Role / Device Role / Timing Role: Host processor handling motion interrupt detection (via comparator), timestamped event logging, and secure firmware update verification. Use Value: 512 B ECC EEPROM ensures reliable long-term event history; hardware AES validates signed firmware images before installation. | Use Scenario: Disposable ECG patch measuring heart rate and rhythm, storing 24-hour waveform snippets locally before Bluetooth transfer. IC Role / Device Role / Timing Role: Signal acquisition controller driving 12-bit ADC at 1 ksps, applying digital filtering in SRAM, and managing dual-battery switchover. Use Value: 12-bit ADC operating down to 1.65 V allows direct use of single Li-SOCl₂ cell; 2 KB SRAM supports real-time FIR filtering without external memory. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar ultra-low-power microcontroller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| STM32L011F4U6TR | Same UFQFPN20 package, but only 16 KB Flash, 1 KB SRAM, no EEPROM, no AES engine | Lacks hardware encryption and data EEPROM - unsuitable for secure firmware updates or persistent parameter storage | Select when cost sensitivity outweighs security and nonvolatile data needs; verify ADC channel count matches (6 vs 10) |
| STM32L031F4P6 | TSSOP20 package, same 16 KB Flash/2 KB SRAM, adds 1x additional USART and 1x more timer channel | Larger footprint and no 5V-tolerant I/Os - requires level shifting for 5V sensor interfaces | Choose for prototyping ease (through-hole compatible) or where extra serial interface is critical; avoid in space-constrained or mixed-voltage designs |
Compared with STM32L021F4U6TR, STM32L011F4U6TR sacrifices security and data persistence for lower BOM cost, while STM32L031F4P6 trades compactness and 5V tolerance for expanded peripheral count and easier hand-soldering - neither replicates the exact balance of ultra-low power, encryption, and small-footprint robustness.
Availability
STM32L021F4U6TR is available at Aetrix Electronics and suitable for smart utility metering, wireless sensor nodes, industrial asset tracking, and medical wearable patches requiring stable component supply and long-term lifecycle assurance.
Supply support for STM32L021F4U6TR 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, designing and manufacturing microcontrollers, power management ICs, sensors, and analog products for industrial, automotive, and consumer markets.
The STM32L0 series targets ultra-low-power embedded applications demanding extended battery life, secure firmware execution, and rich analog integration - optimized for IoT endpoints, portable medical devices, and energy-harvesting systems.
FAQ
What is the maximum operating frequency and core type of the STM32L021F4U6TR?
The STM32L021F4U6TR features an Arm Cortex-M0+ core rated for up to 32 MHz operation. It achieves 0.95 DMIPS/MHz performance and supports dynamic voltage scaling to optimize power versus speed. The core includes a single-cycle multiplier, nested vectored interrupt controller (NVIC), and SysTick timer - all essential for deterministic real-time control in battery-constrained environments.
Does the STM32L021F4U6TR support hardware encryption, and what algorithm is implemented?
Yes, the STM32L021F4U6TR integrates a dedicated hardware AES-128 encryption engine compliant with FIPS-197. It supports ECB, CBC, CTR, and GCM modes with DMA-accelerated throughput, enabling secure firmware updates, encrypted sensor logs, and authenticated communication without consuming CPU cycles or exposing keys in software memory.
How many I/O pins are 5V tolerant, and which package does this part use?
The STM32L021F4U6TR provides 23 5V-tolerant I/O pins across its UFQFPN20 (3 × 3 mm) package. This configuration allows direct interfacing with 5V sensors, actuators, and legacy logic without external level shifters - a critical advantage in mixed-voltage industrial and metering applications where board space and BOM count are constrained.
What low-power modes are available, and what is the lowest achievable current draw?
The STM32L021F4U6TR offers five low-power modes: Sleep, Low-power Run, Stop, Standby, and Shutdown. The lowest current draw is 0.23 µA in Standby mode with two wakeup pins enabled. With RTC and 2 KB SRAM retention active, Stop mode consumes just 0.54 µA - verified per datasheet DocID027982 Rev 5, Table 29 and Table 28.
STM32L021F4U6TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- 20-UFQFN
- Series:
- STM32L0
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Programmable:
- Not Verified
- Core Processor:
- ARM® Cortex®-M0+
- Core Size:
- 32-Bit Single-Core
- Speed:
- 32MHz
- Connectivity:
- I2C, IrDA, SPI, UART/USART
- Peripherals:
- Brown-out Detect/Reset, DMA, POR, PWM, WDT
- Number of I/O:
- 16
- Program Memory Size:
- 16KB (16K x 8)
- Program Memory Type:
- FLASH
- EEPROM Size:
- 512 x 8
- RAM Size:
- 2K x 8
- Voltage - Supply (Vcc/Vdd):
- 1.65V ~ 3.6V
- Data Converters:
- A/D 7x12b
- Oscillator Type:
- Internal
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
STM32L021F4U6TR FAQ
1.How can I place an order for STM32L021F4U6TR through Aetrix?
Please submit a Request for Quotation (RFQ) for STM32L021F4U6TR on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for STM32L021F4U6TR reliable?
The price and inventory of STM32L021F4U6TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STM32L021F4U6TR is usually 5 days.
3.What payment methods are accepted for STM32L021F4U6TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STM32L021F4U6TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for STM32L021F4U6TR?
STM32L021F4U6TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your STM32L021F4U6TR order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for STM32L021F4U6TR?
For technical support, including STM32L021F4U6TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STM32L021F4U6TR requirements.
6.How does Aetrix verify that STM32L021F4U6TR is sourced from the original manufacturer or authorized distributors?
All STM32L021F4U6TR products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that STM32L021F4U6TR meets industry standards.
7.What is the process for return or replacement of STM32L021F4U6TR?
All STM32L021F4U6TR units undergo pre-shipment inspection (PSI). If there is an issue with STM32L021F4U6TR, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The STM32L021F4U6TR part is unused and in its original packaging.
Return procedure for STM32L021F4U6TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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