STMicroelectronics STM8S903F3U3TR

Overview

STM8S903F3U3TR 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, and I²C interfaces, and supports low-power operation down to 2.95 V. It is used in cost-sensitive industrial control panels requiring deterministic real-time response and firmware-upgradable sensor nodes.

For engineers reviewing the STM8S903F3U3TR datasheet, STM8S903F3U3TR pinout, STM8S903F3U3TR application, or STM8S903F3U3TR equivalent, key selection criteria include its 20-pin TSSOP package, 16 MHz max CPU frequency at 3.3 V, true data EEPROM endurance (300 kcycle), SWIM debug interface, and support for LIN master mode over UART.

Technical Context

The STM8S903F3U3TR implements a Harvard-architecture 8-bit core with 3-stage pipeline and extended instruction set, enabling single-cycle execution for most instructions. Its clock system includes four selectable sources: external crystal, external clock, user-trimmable 16 MHz RC, and low-power 128 kHz RC - all monitored by a clock security system.

Interrupt handling uses a nested controller supporting 32 vectors and up to 28 external interrupts across 7 priority levels. Memory subsystem includes segmented Flash with error correction logic, dedicated 640-byte EEPROM with hardware wear leveling, and RAM with retention during active-halt mode.

Key Specifications

Pinout & Package

STM8S903F3U3TR is housed in a 20-pin TSSOP package (4.4 mm body width) with 0.65 mm pitch, optimized for compact industrial PCB layouts and automated assembly.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-bit microcontroller applications.

Compared with STM8S003F3P6, the STM8S903F3U3TR provides triple the EEPROM capacity and hardware LIN support - critical for self-calibrating nodes. Against EFM8BB10F8G-A-QFN20, it offers superior embedded data persistence and automotive protocol acceleration at lower system-level BOM cost.

Availability

STM8S903F3U3TR is available at Aetrix Electronics and suitable for industrial sensor nodes, smart HVAC actuators, entry-level PLC I/O modules, and appliance control boards requiring stable component supply across multi-year production cycles.

Supply support for STM8S903F3U3TR 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-optimized, high-reliability 8-bit control applications, emphasizing low-power operation, embedded nonvolatile memory, and robust peripherals for industrial automation and white goods.

FAQ

Does STM8S903F3U3TR support in-system programming via SWIM?

Yes. The device features a Single-Wire Interface Module (SWIM) that enables full in-circuit programming and debugging using only one dedicated pin (SWIM). No external debugger hardware is required beyond a SWIM-compatible programmer such as ST-LINK/V2, and firmware updates can be performed without removing the MCU from the target board.

What is the maximum ADC sampling rate achievable on STM8S903F3U3TR?

The 10-bit ADC supports up to 1 MSPS conversion rate when configured in continuous scan mode with prescaler = 0 and fCPU = 16 MHz. Actual throughput depends on channel count and trigger source; for 7-channel scan with auto-increment, typical effective rate is ~140 kSPS with 12 ADC clocks per conversion.

Can the internal 16 MHz RC oscillator be calibrated for improved accuracy?

Yes. The internal 16 MHz RC oscillator includes a user-trimmable calibration register (CLK_HSICALR) allowing adjustment in ±1% steps across the full operating voltage and temperature range. Factory calibration value is stored in option bytes, and runtime trimming can achieve ±0.5% accuracy under stable conditions.

Is there hardware support for PWM generation with complementary outputs and dead-time control?

Yes. The advanced control timer (TIM1) provides 4 CAPCOM channels, 3 complementary outputs, and programmable dead-time insertion (1–1023 ns resolution). This enables direct driving of half-bridge or three-phase inverter topologies without external gate driver logic or software-based dead-time management.