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STMicroelectronics STM8S903K3U3
- Part No.:
- STM8S903K3U3
- Manufacturer:
- STMicroelectronics
- Category:
- Microcontrollers
- Package:
- 32-UFQFN Exposed Pad
- Datasheet:
-
STM8S903K3U3.pdf
- Description:
- IC MCU 8BIT 8KB FLASH 32UFQFPN
- Quantity:
- Payment:
- Shipping:
Inventory:3,283
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Product details
Overview
STM8S903K3 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-designed for cost-sensitive industrial control and sensor interface applications requiring low-power operation and robust I/O.
For engineers reviewing the STM8S903K3 datasheet, STM8S903K3 pinout, STM8S903K3 application, or STM8S903K3 equivalent, key selection criteria include its 32-pin LQFP/UFQFPN package, 2.95–5.5 V supply range, nested interrupt controller with 32 vectors, and support for SmartCard/IrDA/LIN via UART.
Technical Context
The STM8S903K3 implements a Harvard-architecture 8-bit core with 3-stage pipeline and extended instruction set, enabling efficient code density and deterministic timing. Its clock system includes four independent sources: external crystal, external clock input, user-trimmable 16 MHz RC, and low-power 128 kHz RC-with clock security monitoring and flexible peripheral gating.
Interrupt handling uses a nested controller supporting up to 28 external interrupts across 7 vectors, while memory subsystem includes Flash with 20-year data retention at 55 °C (10 kcycles) and true data EEPROM rated for 300 kcycles endurance-both accessible via SWIM single-wire debug interface.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Core Architecture | STM8 8-bit Harvard core with 3-stage pipeline and extended instruction set-enables high code efficiency and real-time determinism. |
| Max Clock Frequency | 16 MHz-supports real-time control loops and communication protocols at full speed across 2.95–5.5 V supply range. |
| Flash Memory | 8 Kbytes Flash with 20-year data retention at 55 °C after 10,000 write/erase cycles-suitable for field-upgradable firmware in industrial deployments. |
| Data EEPROM | 640 bytes true data EEPROM with 300,000-cycle endurance-provides reliable nonvolatile parameter storage without external components. |
| ADC Resolution & Channels | 10-bit ADC with ±1 LSB INL and up to 7 external + 1 internal multiplexed inputs-enables precise analog sensing in motor control or environmental monitoring. |
| Communication Peripherals | UART (with SmartCard/IrDA/LIN), SPI (up to 8 Mbit/s), and I²C (up to 400 kbit/s)-supports mixed-protocol connectivity in compact embedded nodes. |
| I/O Count & Type | Up to 28 I/Os in 32-pin packages, including 21 high-sink outputs-delivers direct LED driving or relay control without external buffers. |
Pinout & Package
The STM8S903K3 is available in LQFP32 (7 × 7 mm), UFQFPN32 (5 × 5 mm), and SDIP32 (400 mil) packages. All variants share identical pin functionality and signal mapping per datasheet DS6210 Rev 13 Sections 5.4–5.5.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VDD | Power supply | Main 2.95–5.5 V supply rail; requires local 100 nF decoupling near pin. |
| VSS | Ground reference | Digital ground return; separate analog ground not required but recommended for ADC accuracy. |
| NRST | Active-low reset input | Asynchronous reset with internal pull-up; accepts external push-button or supervisor IC assertion. |
| SWIM | Single-wire debug interface | Enables programming and real-time debugging using ST-LINK/V2 or compatible tools-no dedicated JTAG pins needed. |
| PA0–PA7 | Programmable GPIO / alternate functions | Support UART1_TX/RX, SPI_CLK/MOSI/MISO, I²C_SCL/SDA, TIM1_CH1–CH4, ADC_IN0–IN7-enabling flexible peripheral remapping. |
| PB0–PB7 | Programmable GPIO / alternate functions | Include TIM5_CH1–CH3, TIM6_CLK, AWU, beeper output-used for timer-based wake-up and audible feedback generation. |
| PC0–PC7 | Programmable GPIO / alternate functions | Support TIM1 complementary outputs, dead-time insertion, and synchronization signals-critical for motor gate drive timing control. |
Key Features
| Feature | Design Value |
|---|---|
| Low-power clock sources | Integrated 16 MHz RC (user-trimmable ±1%) and 128 kHz RC-eliminates need for external crystals in battery-powered applications. |
| Advanced control timer (TIM1) | 16-bit timer with 4 CAPCOM channels, 3 complementary outputs, and hardware dead-time insertion-enables precise 3-phase motor control without software overhead. |
| Robust I/O design | 21 high-sink I/Os capable of 20 mA per pin-directly drives LEDs, relays, or optocouplers without external drivers. |
| Memory reliability | Flash data retention guaranteed for 20 years at 55 °C after 10,000 cycles; EEPROM endurance rated at 300,000 cycles-ensures long-term field reliability. |
| Debug & programming | SWIM single-wire interface supports flash programming, breakpoint debugging, and register inspection-reduces PCB footprint vs. multi-pin debug headers. |
Applications
| Industrial Sensor Node | Smart Lighting Controller |
|---|---|
|
Use Scenario: Standalone temperature/humidity sensor node with RS-485 backhaul and local LED status indication. IC Role / Device Role / Timing Role: Central MCU managing ADC sampling, UART-to-RS485 translation, and PWM-dimmed status LEDs. Use Value: Integrated UART with LIN/SmartCard mode enables direct RS-485 transceiver interfacing; 21 high-sink I/Os drive LEDs without external drivers. |
Use Scenario: DALI-compliant LED driver with thermal foldback and overcurrent protection. IC Role / Device Role / Timing Role: Real-time current regulation controller using TIM1 complementary outputs and dead-time insertion for half-bridge FET drive. Use Value: Hardware dead-time prevents shoot-through in bridge configurations; 10-bit ADC monitors sense resistor voltage with ±1 LSB linearity. |
| Home Appliance Control Panel | Energy Meter Front-End |
|
Use Scenario: Microwave oven control board with keypad scan, buzzer feedback, and display backlight PWM. IC Role / Device Role / Timing Role: System coordinator handling touch-key scanning, beeper tone generation, and 8-bit basic timer-driven backlight dimming. Use Value: Integrated beeper module eliminates external oscillator; auto-wake-up timer enables low-power keypad monitoring with sub-1 µA sleep current. |
Use Scenario: Single-phase electricity meter front-end measuring voltage/current via shunt/resistive dividers and communicating via I²C to metrology ASIC. IC Role / Device Role / Timing Role: Isolated communication gateway and calibration parameter manager using I²C interface and EEPROM storage. Use Value: 640-byte EEPROM stores meter constants and calibration coefficients with 300 kcycle endurance-avoids external serial EEPROM. |
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 STM8 core, 8 Kbytes Flash, but only 128 bytes EEPROM and no advanced control timer (TIM1); TSSOP20 package limits I/O count to 16. | Limited to simpler control tasks without motor drive or high-channel ADC requirements. | Select when cost and footprint are critical and advanced peripherals are unnecessary. |
| STM8L051F3P6 | Ultra-low-power variant with 3.6 µA active-halt current, but reduced max frequency (16 MHz only at VDD ≥ 3.0 V) and no 16-bit advanced timer. | Better suited for battery-powered sensors than mains-powered industrial controllers. | Prefer for energy harvesting or coin-cell applications where runtime outweighs processing capability. |
Compared with STM8S003F3P6 and STM8L051F3P6, the STM8S903K3 uniquely combines full 32-pin I/O access, TIM1 with dead-time control, and 640-byte EEPROM-making it optimal for industrial edge nodes requiring both analog precision and actuator timing integrity.
Availability
STM8S903K3 is available at Aetrix Electronics and suitable for industrial sensor nodes, smart lighting controllers, home appliance panels, and energy meter front-ends requiring stable component supply and long-term production support.
Supply support for STM8S903K3 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, specializing in microcontrollers, power management, and automotive ICs with broad manufacturing scale and industrial qualification expertise.
The STM8S series targets cost-optimized, robust 8-bit control applications in industrial automation, appliance control, and sensor interfaces-emphasizing ease of use, low system cost, and long-term availability.
FAQ
What debug interface does the STM8S903K3 support?
The STM8S903K3 uses the SWIM (Single-Wire Interface Module) protocol for programming and debugging. It requires only one dedicated pin (SWIM) and ground, supporting full flash read/write, breakpoint setting, and real-time register inspection via ST-LINK/V2 or compatible debuggers-no JTAG header or additional pins needed.
Does the STM8S903K3 support hardware CRC calculation?
No, the STM8S903K3 does not include a dedicated hardware CRC peripheral. CRC computation must be implemented in firmware using standard polynomial algorithms (e.g., CRC-8 or CRC-16), leveraging the MCU's efficient 8-bit ALU and loop instructions for acceptable performance in communication frame validation.
Can the internal 16 MHz RC oscillator meet USB or Ethernet timing requirements?
No-the internal 16 MHz RC oscillator has ±1% factory trim and ±2% variation over temperature/voltage, which exceeds the ±0.25% tolerance required for full-speed USB or Ethernet PHY clocks. External crystal or precision oscillator is mandatory for such applications.
How many unique ID bits does the STM8S903K3 provide?
The STM8S903K3 provides a factory-programmed 96-bit unique identifier stored in read-only registers (addresses 0x4860–0x486B). This value is globally unique per device and可用于 secure boot key derivation, device authentication, or license binding in firmware.
STM8S903K3U3 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 ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
STM8S903K3U3 FAQ
1.How can I place an order for STM8S903K3U3 through Aetrix?
Please submit a Request for Quotation (RFQ) for STM8S903K3U3 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 STM8S903K3U3 reliable?
The price and inventory of STM8S903K3U3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STM8S903K3U3 is usually 5 days.
3.What payment methods are accepted for STM8S903K3U3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STM8S903K3U3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for STM8S903K3U3?
STM8S903K3U3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your STM8S903K3U3 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 STM8S903K3U3?
For technical support, including STM8S903K3U3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STM8S903K3U3 requirements.
6.How does Aetrix verify that STM8S903K3U3 is sourced from the original manufacturer or authorized distributors?
All STM8S903K3U3 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 STM8S903K3U3 meets industry standards.
7.What is the process for return or replacement of STM8S903K3U3?
All STM8S903K3U3 units undergo pre-shipment inspection (PSI). If there is an issue with STM8S903K3U3, 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 STM8S903K3U3 part is unused and in its original packaging.
Return procedure for STM8S903K3U3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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