STM8S903K3T6 - 8-bit MCU, 8KB Flash, 16MHz | STMicroelectronics
MPN: STM8S903K3T6 β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.15 | $2.15 |
| 10 | $1.93 | $19.30 |
| 100 | $1.72 | $172.00 |
| 500 | $1.55 | $775.00 |
| 1,000 | $1.38 | $1,380.00 |
Drop-in alternatives for STM8S903K3T6 β same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
STM8S903K3T6C
β Drop-Inπ Reference alternative (not in catalog)
STM8S903K3T6CTR
β Drop-Inπ Reference alternative (not in catalog)
STM8S903K3T6 Maximum Ratings & Electrical Characteristics
| Core | STM8 8-bit |
| Clock Speed | 16 MHz |
| Flash Memory | 8 KB (8K x 8) |
| RAM Size | 1 KB |
| EEPROM Size | 640 bytes |
| Supply Voltage | 2.95 V to 5.5 V |
| I/O Ports | 16 |
| ADC Resolution | 10-bit |
| ADC Channels | 7 |
| Timers | 2 x 16-bit |
| UART | 1 |
| SPI | 1 |
| I2C | 1 |
| Package | LQFP-32 |
| Mounting Type | Surface Mount |
| Operating Temperature | -40C to +85C |
| RoHS Status | Compliant |
STM8S903K3T6 Pin Configuration
| Pin 1 | VDD β Digital power supply |
| Pin 2 | PA1 β General purpose I/O / ADC input |
| Pin 3 | PA2 β General purpose I/O / ADC input |
| Pin 4 | PA3 β General purpose I/O / ADC input |
| Pin 5 | VSS β Digital ground |
| Pin 6 | PA4 β General purpose I/O / ADC input |
| Pin 7 | PA5 β General purpose I/O / ADC input |
| Pin 8 | PA6 β General purpose I/O / ADC input |
| Pin 9 | PB0 β General purpose I/O / SPI MOSI |
| Pin 10 | PB1 β General purpose I/O / SPI MISO |
| Pin 11 | PB2 β General purpose I/O / SPI SCK |
| Pin 12 | PB3 β General purpose I/O / I2C SCL |
| Pin 13 | PB4 β General purpose I/O / I2C SDA |
| Pin 14 | PB5 β General purpose I/O / UART TX |
| Pin 15 | PB6 β General purpose I/O / UART RX |
| Pin 16 | VDDIO β I/O power supply |
| Pin 17 | PC0 β General purpose I/O / ADC input |
| Pin 18 | PC1 β General purpose I/O / ADC input |
| Pin 19 | PC2 β General purpose I/O / ADC input |
| Pin 20 | PC3 β General purpose I/O / ADC input |
| Pin 21 | PC4 β General purpose I/O / ADC input |
| Pin 22 | PC5 β General purpose I/O / ADC input |
| Pin 23 | PC6 β General purpose I/O / ADC input |
| Pin 24 | PC7 β General purpose I/O / ADC input |
| Pin 25 | VDDA β Analog power supply |
| Pin 26 | VSSA β Analog ground |
| Pin 27 | PD0 β General purpose I/O / OSC_IN |
| Pin 28 | PD1 β General purpose I/O / OSC_OUT |
| Pin 29 | PD2 β General purpose I/O / timer input |
| Pin 30 | PD3 β General purpose I/O / timer output |
| Pin 31 | PD4 β General purpose I/O / timer output |
| Pin 32 | PD5 β General purpose I/O / timer output |
Safe Operating Area (SOA) & Thermal Characteristics
No official SOA curve available for this digital IC. Always operate within absolute maximum ratings specified in the datasheet. Ensure adequate cooling and derate as needed.
Typical Applications
STM8S903K3T6 is suitable for 6 applications: Industrial Control Systems, Home Automation, Consumer Electronics, Automotive Body Electronics, Sensor Interfacing and Data Logging, Motor Control.
Industrial Control Systems
The STM8S903K3T6 is well-suited for industrial control systems due to its robust 8-bit core, wide operating voltage range, and integrated peripherals. The 10-bit ADC allows direct interfacing with analog sensors such as temperature probes and pressure transducers, while the UART, SPI, and I2C interfaces enable communication with external devices like motor drivers and human-machine interfaces (HMIs). The device's 16 MHz clock speed provides sufficient processing power for real-time control loops, and the 8KB Flash memory can accommodate moderate-sized firmware. The -40C to +85C operating temperature range ensures reliable operation in factory environments. In a typical application, the MCU reads sensor data, processes it using control algorithms, and outputs control signals to actuators via the GPIO pins. The integrated EEPROM allows storing calibration parameters and system settings without external memory. The low-power modes help reduce energy consumption in systems that operate intermittently.
Recommended
Home Automation
In home automation, the STM8S903K3T6 serves as a cost-effective controller for smart lighting, thermostats, and security systems. Its 2.95V to 5.5V supply range allows direct operation from standard 3.3V or 5V power supplies, simplifying power design. The I2C interface enables connection to environmental sensors like the BME280 for temperature, humidity, and pressure monitoring. The UART interface can be used to communicate with Wi-Fi or Zigbee modules for remote control and monitoring. The 10-bit ADC can read analog light sensors to implement automatic lighting control. The device's low-power Halt mode reduces standby current to microamps, extending battery life in wireless sensor nodes. The 8KB Flash memory is sufficient for implementing communication protocols and control logic. The integrated EEPROM allows storing user preferences and device configurations. The compact LQFP-32 package fits well on small PCB designs for in-wall or in-ceiling mounting.
Recommended
Consumer Electronics
The STM8S903K3T6 is ideal for consumer electronics such as remote controls, small appliances, and toys. Its low cost and integrated peripherals reduce overall system cost. The 16 MHz clock speed provides responsive user interface handling, while the 10-bit ADC can read analog inputs like potentiometers for volume control. The SPI interface can drive small OLED or LCD displays for status indication. The UART interface enables communication with other devices or debugging. The device's wide supply voltage range allows operation from two AA batteries (3V) or a USB 5V supply. The low-power modes are crucial for battery-powered devices, extending operational life. The 8KB Flash memory is sufficient for implementing user interface logic and simple state machines. The integrated EEPROM can store user settings such as volume levels or last-used modes. The compact package and minimal external component requirements make it suitable for space-constrained designs.
Recommended
Automotive Body Electronics
The STM8S903K3T6 is designed for automotive body electronics applications such as window lift control, mirror adjustment, and lighting control. Its wide supply voltage range (2.95V to 5.5V) accommodates the fluctuating battery voltage in automotive environments. The 10-bit ADC can read analog sensors like position sensors for mirror adjustment. The two 16-bit timers can generate PWM signals for motor speed control or LED dimming. The UART interface enables communication with other ECUs in the vehicle network. The device's robust design includes protection against electrical transients, making it suitable for the harsh automotive environment. The -40C to +85C operating temperature range covers the typical automotive temperature requirements. The 8KB Flash memory is sufficient for implementing control algorithms and diagnostic routines. The integrated EEPROM can store calibration data and fault codes. The LQFP-32 package is suitable for PCB designs in door modules and body control modules.
Recommended
Sensor Interfacing and Data Logging
The STM8S903K3T6 excels in sensor interfacing and data logging applications due to its integrated 10-bit ADC, EEPROM, and low-power modes. The ADC can sample multiple analog sensors, while the EEPROM provides non-volatile storage for logged data. The UART or SPI interface can be used to transfer logged data to a host computer or external memory. The device's low-power modes allow battery-powered data loggers to operate for extended periods. The 16 MHz clock speed enables fast sampling rates for dynamic signals. The wide supply voltage range allows operation from various battery chemistries. The 8KB Flash memory can store the logging firmware and configuration parameters. The integrated EEPROM with 100,000 write/erase cycles is suitable for frequent data logging. The compact package and minimal external components make it ideal for portable data loggers. The -40C to +85C temperature range allows operation in outdoor environments.
Recommended
Motor Control
The STM8S903K3T6 is suitable for simple motor control applications such as DC motor speed control and stepper motor positioning. The two 16-bit timers can generate PWM signals with adjustable duty cycle and frequency, enabling precise motor speed control. The 10-bit ADC can read current sense resistors for closed-loop control. The UART interface allows communication with a host controller for command input and status reporting. The device's 16 MHz clock speed provides sufficient processing power for implementing PID control algorithms. The wide supply voltage range allows direct interfacing with motor driver ICs. The 8KB Flash memory can store the control firmware and calibration data. The integrated EEPROM can store motor parameters and tuning coefficients. The LQFP-32 package provides enough I/O pins for connecting to motor drivers, encoders, and limit switches. The device's robust design ensures reliable operation in industrial environments.
Recommended
Recommended Products Summary
Engineering reference data for STM8S903K3T6 β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | STM8S903K3T6C | STM8S003K3T6C | STM8S103K3T6C | MC9S08PA8VLC |
|---|---|---|---|---|---|
| Package | LQFP-32 | LQFP-32 - same | TSSOP-20 - different | TSSOP-20 - different | LQFP-32 - different pinout |
| Brand | STMicroelectronics | STMicroelectronics | STMicroelectronics | STMicroelectronics | NXP Semiconductors |
| Clock Speed | 16 MHz | 16 MHz | 16 MHz | 16 MHz | 20 MHz |
| Flash Memory | 8 KB | 8 KB | 8 KB | 8 KB | 8 KB |
| RAM Size | 1 KB | 1 KB | 1 KB | 1 KB | 1 KB |
| EEPROM Size | 640 bytes | 640 bytes | 128 bytes | 640 bytes | [DATA_NEEDED] |
| ADC Resolution | 10-bit | 10-bit | 10-bit | 10-bit | 12-bit |
| Supply Voltage | 2.95V to 5.5V | 2.95V to 5.5V | 2.95V to 5.5V | 2.95V to 5.5V | 2.7V to 5.5V |
Key Differentiators
- True data EEPROM with read-while-write (vs STM8S003K3T6C)
- 32-pin LQFP package with more I/O (vs STM8S103K3T6C)
- Wide supply voltage range (vs MC9S08PA8VLC)
Design Notes
The STM8S903K3T6 requires a stable power supply. Place a 100nF ceramic capacitor as close as possible to each VDD and VDDA pin, and a 1uF to 10uF bulk capacitor on the main power rail. The VDDA pin should be connected to the same supply as VDD through a ferrite bead or low-value resistor to filter high-frequency noise, ensuring accurate ADC readings. The VSSA pin should be connected to the ground plane with minimal impedance.
For the LQFP-32 package, ensure proper solder pad design per IPC-7351 standards. The exposed pad (if present) should be connected to ground with multiple vias for thermal relief. Keep high-speed signals (SPI, UART) away from the crystal oscillator pins (PD0, PD1) to avoid interference. Route the ADC input traces away from digital traces to minimize noise coupling.
When using the internal RC oscillator, note that its accuracy is Β±1% over temperature, which may not be sufficient for time-critical applications like UART communication at high baud rates. For such applications, use an external crystal (e.g., 16 MHz) connected to OSC_IN and OSC_OUT with appropriate load capacitors. Also, ensure the reset pin (NRST) is properly pulled up with a 100nF capacitor to ground to prevent spurious resets.
Compliance Information
RoHS compliant per STMicroelectronics product page. Not AEC-Q100 qualified for automotive applications.
