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STMicroelectronics STM8S903K3U6
- Part No.:
- STM8S903K3U6
- Manufacturer:
- STMicroelectronics
- Category:
- Microcontrollers
- Package:
- 32-UFQFN Exposed Pad
- Datasheet:
-
STM8S903K3U6.pdf
- Description:
- IC MCU 8BIT 8KB FLASH 32UFQFPN
- Quantity:
- Payment:
- Shipping:
Inventory:2,938
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Product details
Overview
STM8S903K3U6 from STMicroelectronics is an 8-bit microcontroller featuring a 16 MHz STM8 core, 8 Kbytes Flash, 1 Kbyte RAM, and 640 bytes EEPROM. It integrates a 10-bit ADC with 7 multiplexed channels, UART, SPI, I²C, and two 16-bit timers - used in industrial sensor nodes requiring low-power operation and robust I/O drive capability.
For engineers reviewing the STM8S903K3U6 datasheet, STM8S903K3U6 pinout, STM8S903K3U6 application, or STM8S903K3U6 equivalent, key selection criteria include its 32-pin LQFP/UFQFPN package compatibility, 28 I/Os (21 high-sink), 2.95–5.5 V supply range, and support for SmartCard/IrDA/LIN master modes via UART.
Technical Context
The STM8S903K3U6 implements a Harvard-architecture 8-bit core with 3-stage pipeline and extended instruction set, enabling deterministic real-time control. Its clock system includes four sources: external crystal, external clock input, user-trimmable 16 MHz RC, and low-power 128 kHz RC - all managed by a clock security system with monitor.
Interrupt handling uses a nested controller supporting 32 interrupts and up to 28 external vectors. Memory subsystem includes Flash with 20-year data retention at 55 °C after 10 kcycles and true data EEPROM rated for 300 kwrite cycles - both accessible via SWIM single-wire interface for debug and programming.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Core | 16 MHz STM8 8-bit Harvard architecture with 3-stage pipeline and extended instruction set - enables deterministic timing for real-time control loops. |
| Flash Memory | 8 Kbytes with 20-year data retention at 55 °C after 10,000 write/erase cycles - supports field firmware updates without premature wear-out. |
| Data EEPROM | 640 bytes true data EEPROM, endurance 300,000 write cycles - stores calibration data, device IDs, or configuration parameters reliably across product lifetime. |
| ADC | 10-bit ±1 LSB ADC with up to 7 external channels + 1 internal reference channel - provides sufficient resolution for analog sensor interfacing in industrial monitoring. |
| I/O Count & Drive | Up to 28 I/Os in 32-pin packages, including 21 high-sink outputs - directly drives LEDs, relays, or logic-level MOSFETs without external buffers. |
| Supply Voltage | 2.95 to 5.5 V operating range - compatible with both 3.3 V and 5 V legacy industrial systems without level-shifting. |
| Low-Power Modes | Wait, active-halt, and halt modes with individual peripheral clock gating - reduces system power to µA-range during idle periods in battery-powered nodes. |
Pinout & Package
LQFP32 (7 × 7 mm) and UFQFPN32 (5 × 5 mm) packages are supported; STM8S903K3U6 specifically uses the LQFP32 variant per ordering code suffix "U6". Both packages provide identical pin mapping and electrical characteristics.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VDD, VSS | Power supply and ground | Dual VDD pins (pins 8, 26) and dual VSS pins (pins 9, 27) reduce supply impedance and improve noise immunity in mixed-signal operation. |
| NRST | Active-low reset input | Internal pull-up ensures reliable power-on reset; accepts external reset pulses or watchdog timeout signals. |
| PA0–PA7 | Port A general-purpose I/O | 8-bit port with alternate functions including UART1_TX, SPI_MOSI, TIM1_CH1, ADC_IN0–7 - enables flexible peripheral remapping. |
| PB0–PB7 | Port B general-purpose I/O | 8-bit port supporting UART1_RX, SPI_SCK, TIM1_CH2, TIM5_CH1, I²C_SCL/SDA - allows concurrent serial and timer usage. |
| PC0–PC7 | Port C general-purpose I/O | 8-bit port with TIM1_CH3/CH4, TIM5_CH2/CH3, ADC_VREF+, and SWIM debug interface - supports debug and analog reference routing. |
| PD0–PD7 | Port D general-purpose I/O | 8-bit port including TIM1_ETR, TIM5_ETR, and high-sink capable pins - suitable for driving loads up to 20 mA sink per pin. |
Key Features
| Feature | Design Value |
|---|---|
| Single-Wire Interface Module (SWIM) | On-chip debug and programming interface using only one pin - eliminates need for JTAG header space and simplifies PCB layout. |
| Advanced Control Timer (TIM1) | 16-bit timer with 4 CAPCOM channels, 3 complementary outputs, dead-time insertion - enables precise motor phase control in BLDC drivers. |
| Flexible Clock System | Four independent clock sources with automatic failover and clock monitor - ensures system reliability in environments with unstable crystal oscillation. |
| High-Sink I/O Capability | 21 pins rated for 20 mA sink current - directly interfaces with LED indicators, optocouplers, or N-channel MOSFET gates without external drivers. |
| Integrated Analog Peripherals | 10-bit ADC with scan mode, analog watchdog, and internal VREF measurement - supports autonomous sensor monitoring without CPU intervention. |
Applications
| Industrial Sensor Node | Smart Metering Interface |
|---|---|
Use Scenario: Standalone temperature/humidity sensor node with RS-485 backhaul and local display. IC Role / Device Role / Timing Role: Main controller managing ADC sampling, UART-to-RS485 translation, and LCD segment driver timing. Use Value: 28 I/Os accommodate sensor inputs, display segments, and communication lines; low-power modes extend battery life beyond 5 years. |
Use Scenario: Pulse-counting interface between mechanical utility meter and wireless communication module. IC Role / Device Role / Timing Role: Edge-triggered counter capturing meter reed-switch pulses while maintaining accurate timebase for timestamping. Use Value: TIM1's external trigger input (ETR) and auto-wakeup timer enable precise pulse capture with sub-millisecond resolution and sleep-state responsiveness. |
| Home Appliance Motor Control | Automotive Body Controller Subsystem |
Use Scenario: Fan speed regulator in HVAC unit using single-phase BLDC motor with hall-effect feedback. IC Role / Device Role / Timing Role: Real-time commutation controller generating complementary PWM outputs with programmable dead-time. Use Value: TIM1's 3 complementary outputs and hardware dead-time insertion eliminate software timing errors and prevent shoot-through in half-bridge drivers. |
Use Scenario: Door lock actuator controller receiving LIN commands and driving solenoid latch with status feedback. IC Role / Device Role / Timing Role: LIN master node implementing physical layer timing, frame assembly, and fault-safe current limiting. Use Value: UART's built-in LIN master mode handles synchronization, checksum, and break detection - reducing firmware overhead and improving protocol compliance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 8-bit microcontroller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| STM8S003F3P6 | Same core, but 8 Kbyte Flash, 1 Kbyte RAM, no data EEPROM; TSSOP20 package (20-pin). | Limited I/O count (16) and missing dedicated EEPROM - unsuitable for applications requiring persistent non-volatile storage of calibration data. | Select when board space is constrained and EEPROM is unnecessary; verify pin compatibility for existing LQFP32 layouts. |
| STM8L051F3P6 | Ultra-low-power variant with 8 Kbyte Flash, 1 Kbyte RAM, 640 byte EEPROM, but max 16 MHz only at 3.0–3.6 V; no high-sink I/Os. | Optimized for sub-µA sleep current, but lacks 21 high-sink outputs and 5 V tolerance - incompatible with 5 V industrial bus interfaces. | Prefer for battery-powered IoT endpoints where energy efficiency outweighs I/O drive strength and voltage flexibility. |
Compared with STM8S003F3P6, STM8S903K3U6 offers 28 I/Os and integrated EEPROM for field-programmable calibration; versus STM8L051F3P6, it delivers higher I/O drive, 5 V tolerance, and broader voltage range - making it more suitable for industrial control and legacy 5 V system integration.
Availability
STM8S903K3U6 is available at Aetrix Electronics and suitable for industrial sensor nodes, smart metering interfaces, home appliance motor controllers, and automotive body controller subsystems requiring stable component supply and long-term manufacturability.
Supply support for STM8S903K3U6 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 devices, sensors, and analog ICs for industrial, automotive, and consumer markets.
The STM8S series targets cost-sensitive, robust 8-bit control applications in industrial automation and appliance control - emphasizing ease of use, low-power operation, and high I/O resilience in electrically noisy environments.
FAQ
What debug interface does STM8S903K3U6 support?
STM8S903K3U6 uses the Single-Wire Interface Module (SWIM), a proprietary ST debug and programming interface requiring only one dedicated pin (SWIM on PC7). It supports full-speed debugging, flash programming, and memory inspection without additional hardware headers or complex setup.
Does STM8S903K3U6 support 5 V operation?
Yes - STM8S903K3U6 operates over 2.95 to 5.5 V, with all I/Os 5 V-tolerant when configured as inputs. Its high-sink outputs deliver up to 20 mA per pin at 5 V, enabling direct interface with legacy 5 V logic and electromechanical loads without level shifters.
Can STM8S903K3U6 generate complementary PWM with dead-time?
Yes - its TIM1 advanced control timer provides three complementary output channels with programmable dead-time insertion (1–1023 ns resolution), synchronized gate drive signals, and fault protection inputs - essential for safe half-bridge and inverter control.
Is there hardware support for LIN bus communication?
Yes - the integrated UART supports LIN master mode with automatic sync field generation, checksum calculation, and break detection. This offloads protocol timing and framing from firmware, ensuring compliance with LIN 2.x specifications without CPU cycle overhead.
STM8S903K3U6 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- 32-UFQFN Exposed Pad
- Series:
- STM8S
- Packaging:
- Tray
- Product Status:
- Active
- Programmable:
- Not Verified
- Core Processor:
- STM8
- Core Size:
- 8-Bit
- Speed:
- 16MHz
- Connectivity:
- I2C, IrDA, LINbus, SPI, UART/USART
- Peripherals:
- Brown-out Detect/Reset, POR, PWM, WDT
- Number of I/O:
- 28
- Program Memory Size:
- 8KB (8K x 8)
- Program Memory Type:
- FLASH
- EEPROM Size:
- 640 x 8
- RAM Size:
- 1K x 8
- Voltage - Supply (Vcc/Vdd):
- 2.95V ~ 5.5V
- Data Converters:
- A/D 7x10b
- Oscillator Type:
- Internal
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
STM8S903K3U6 FAQ
1.How can I place an order for STM8S903K3U6 through Aetrix?
Please submit a Request for Quotation (RFQ) for STM8S903K3U6 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 STM8S903K3U6 reliable?
The price and inventory of STM8S903K3U6 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STM8S903K3U6 is usually 5 days.
3.What payment methods are accepted for STM8S903K3U6?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STM8S903K3U6 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for STM8S903K3U6?
STM8S903K3U6 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your STM8S903K3U6 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 STM8S903K3U6?
For technical support, including STM8S903K3U6 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STM8S903K3U6 requirements.
6.How does Aetrix verify that STM8S903K3U6 is sourced from the original manufacturer or authorized distributors?
All STM8S903K3U6 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 STM8S903K3U6 meets industry standards.
7.What is the process for return or replacement of STM8S903K3U6?
All STM8S903K3U6 units undergo pre-shipment inspection (PSI). If there is an issue with STM8S903K3U6, 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 STM8S903K3U6 part is unused and in its original packaging.
Return procedure for STM8S903K3U6:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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