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STMicroelectronics STM8S903F3U3TR — Microcontrollers & Processors (MCU / MPU / DSP)

STM8S903F3U3TR 8-bit MCU, 16 MHz, 8 KB Flash, UFQFPN-20

MPNSTM8S903F3U3TR
Active

STMicroelectronics STM8S903F3U3TR, 8-bit STM8 core MCU, 16 MHz, 8 KB Flash, 1K x 8 RAM, 640 x 8 EEPROM, 2.95V–5.5V supply, -40°C to 125°C, 20-UFQFPN (3x3 mm), Tape & Reel.

$1.1063Ref. price · indicative, final on quote
STMicroelectronics STM8S903F3U3TR datasheet (PDF)
Independent supplier — new & surplus stockAuthenticity-screened · ESD-safe packingListing updated Jul 2026

Specifications

STM8S903F3U3TR specifications
ParameterValue
SeriesSTM8S
MountingSurface Mount
Oscillator typeInternal
Program memory typeFLASH
Voltage - supply (Vcc (Vdd))2.95V ~ 5.5V
Operating temperature-40°C ~ 125°C (TA)
Speed16MHz
PackageTape & Reel (TR)
RAM size1K x 8
Core size8-Bit
EEPROM size640 x 8
PeripheralsBrown-out Detect/Reset, POR, PWM, WDT
ConnectivityI²C, IrDA, LINbus, SPI, UART/USART
Number of i (O)16
Core processorSTM8
Case20-UFQFN
Data convertersA/D 5x10b
Program memory size8KB (8K x 8)

Product details

16 MHz 8-bit MCU in a 3x3 mm package

The 20-pin UFQFPN package (3x3 mm) saves board area for space-constrained designs like sensor modules or small motor drives.

On-chip peripherals include a 10-bit ADC with five channels, a PWM timer, and a watchdog timer.

The 8 KB Flash and 1 KB RAM limit firmware complexity — a full CANopen or Modbus stack will exceed this budget. It fits best as a dedicated I/O controller, LIN slave, or a simple PWM generator where the code stays under a few kilobytes.

Listed as Active — no last-time-buy or NRND flags. For dual-sourcing resilience, ST's STM8S family includes several pin-compatible density variants (e.g., 16 KB and 32 KB Flash options in the same UFQFPN-20 footprint), though the exact order code should be validated against the BOM.

Frequently asked questions

What is the closest pin-compatible alternative to the STM8S903F3U3TR?

Within the STM8S family, the STM8S903F3 shares the same UFQFPN-20 footprint and pinout as other STM8S903x3 variants. For higher memory, the STM8S903K3 (32 KB Flash) is pin-compatible, though the exact order code should be cross-checked for peripheral differences.

How to program the STM8S903F3U3TR?

Programming is done via the SWIM (Single Wire Interface Module) protocol, supported by ST's ST-Link/V2 programmer and the STVD or STVP toolchain.