STMicroelectronics STM8S903K3T3C

Overview

STM8S903K3T3C from STMicroelectronics is an 8-bit microcontroller featuring a 16 MHz STM8 core, 8 Kbytes Flash, 1 Kbyte RAM, and 640 bytes EEPROM, with integrated 10-bit ADC, UART, SPI, I²C, and two 16-bit timers. It operates from 2.95–5.5 V and targets cost-sensitive industrial control, sensor interface, and appliance motor management applications.

For engineers reviewing the STM8S903K3T3C datasheet, STM8S903K3T3C pinout, STM8S903K3T3C application, or STM8S903K3T3C equivalent, this page delivers verified technical context, package-specific pin functions, real-world use cases, and validated alternative options for embedded firmware development and BOM optimization.

Technical Context

The STM8S903K3T3C implements a Harvard-architecture 8-bit core with 3-stage pipeline and extended instruction set, supporting up to 16 MHz operation across its full voltage range (2.95–5.5 V). Its clock system integrates four sources: low-power crystal oscillator, external clock input, user-trimmable 16 MHz RC, and 128 kHz low-power RC - all monitored by a clock security system.

Interrupt handling uses a nested controller with 32 vectors and up to 28 external interrupt inputs on 7 priority levels. Memory subsystem includes 8 Kbyte Flash with 20-year data retention at 55 °C after 10 kcycles, 640-byte true EEPROM (300 kcycle endurance), and 1 Kbyte RAM - all accessible via SWIM single-wire debug interface.

Key Specifications

Pinout & Package

LQFP32 (7 × 7 mm, 0.8 mm pitch) and UFQFPN32 (5 × 5 mm, 0.5 mm pitch) packages are supported. The STM8S903K3T3C variant uses the LQFP32 package per ordering code T3C suffix and manufacturer documentation (DS6210 Rev 13, Section 11.1).

Key Features

Applications

Equivalent & Alternatives

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

Compared with STM8S003F3P6, the STM8S903K3T3C provides double Flash, integrated EEPROM, and TIM1 for motor control - making it superior for firmware-upgradable industrial nodes. Versus STM8L052C6T6, it trades ultra-low-power modes for lower cost and simpler debug integration, better fitting mains-powered appliances.

Availability

STM8S903K3T3C is available at Aetrix Electronics and suitable for industrial sensor nodes, smart appliance control, energy meter front-ends, and IoT edge gateway subsystems requiring stable component supply, long-term lifecycle support, and consistent parametric performance.

Supply support for STM8S903K3T3C 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 management ICs, sensors, and analog components for industrial, automotive, and consumer markets.

The STM8S series was engineered for cost-sensitive, high-reliability 8-bit embedded control - emphasizing robust I/O, integrated peripherals, and field-programmable Flash in compact packages for white goods, building automation, and industrial equipment.

FAQ

What is the maximum operating frequency of the STM8S903K3T3C and under what conditions?

The STM8S903K3T3C achieves 16 MHz maximum CPU frequency across its full operating voltage range of 2.95–5.5 V, as confirmed in DS6210 Rev 13 Section 10.3.1. This requires proper VCAP decoupling (1 µF ceramic capacitor) and stable clock source - either the internal 16 MHz RC (user-trimmable) or external crystal/oscillator. No derating is needed at 5.5 V or 25 °C.

Does the STM8S903K3T3C support in-circuit debugging, and what interface is used?

Yes, the STM8S903K3T3C supports full in-circuit debugging via the Single-Wire Interface Module (SWIM), which uses only the PB4 pin. This interface enables programming, breakpoint setting, register inspection, and real-time variable monitoring without requiring additional pins or headers - documented in Section 4.2 of DS6210 Rev 13.

How many I/O pins are available on the LQFP32 package, and what is their drive capability?

The STM8S903K3T3C in LQFP32 provides up to 28 I/Os across ports A–D, with 21 designated as high-sink outputs capable of sinking up to 20 mA per pin (Section 10.3.6, Table 43). All pins tolerate 5 V input regardless of VDD level, and include robust immunity against current injection per manufacturer testing.

Is there hardware support for motor control applications, and what peripherals are involved?

Yes, the STM8S903K3T3C includes dedicated motor control hardware in its TIM1 advanced control timer: 16-bit counter, 4 capture/compare channels, 3 complementary outputs with programmable dead-time insertion, and flexible synchronization with other timers. This enables direct generation of 3-phase gate drive signals without external logic or FPGA assistance.