STMicroelectronics STM8S903K3T6CTR

Overview

STM8S903K3T6CTR 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 - used in industrial sensor nodes requiring low-power operation and robust I/O.

For engineers reviewing the STM8S903K3T6CTR datasheet, STM8S903K3T6CTR pinout, STM8S903K3T6CTR application, or STM8S903K3T6CTR equivalent, key selection criteria include its 32-pin LQFP/UFQFPN package, 2.95–5.5 V supply range, nested interrupt controller supporting 32 interrupts, and SWIM single-wire debug interface for cost-sensitive embedded control.

Technical Context

The STM8S903K3T6CTR implements a Harvard-architecture 8-bit core with 3-stage pipeline and extended instruction set, enabling deterministic real-time execution. Its clock system includes four sources: external crystal, external clock input, user-trimmable 16 MHz RC, and low-power 128 kHz RC - all managed by a clock security system with monitor.

Interrupt handling uses a nested controller with 32 vectors and up to 28 external interrupts on 7 priority levels. Memory subsystem comprises 8 Kbytes of Flash (20-year data retention at 55 °C), 640 bytes of true EEPROM (300 kcycle endurance), and 1 Kbyte RAM - all accessible via unified memory map with dedicated register banks.

Key Specifications

Pinout & Package

LQFP32 (7 × 7 mm) and UFQFPN32 (5 × 5 mm) packages are supported; this part uses the LQFP32 variant with 0.8 mm pitch and exposed thermal pad. Pin functions are validated per DS6210 Rev 13 Section 5.4–5.5.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STM8S003F3P6, the STM8S903K3T6CTR adds TIM1 for motor control and 32-pin I/O flexibility; versus STM8L052C6T6, it trades lower sleep current for 5 V tolerance and higher drive strength - making it suitable for industrial 3.3/5 V hybrid systems.

Availability

STM8S903K3T6CTR is available at Aetrix Electronics and suitable for industrial sensor nodes, smart HVAC actuators, energy metering subsystems, and appliance control panels requiring stable component supply and long-term production support.

Supply support for STM8S903K3T6CTR 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 ICs, sensors, and analog components for industrial, automotive, and consumer markets.

The STM8S series targets cost-sensitive, resource-constrained embedded control applications - emphasizing robustness, low-power operation, and toolchain maturity for rapid development of industrial and home appliance systems.

FAQ

What debug interface does the STM8S903K3T6CTR support?

The STM8S903K3T6CTR uses the Single-Wire Interface Module (SWIM), a proprietary ST debug protocol requiring only one GPIO pin for full programming and real-time debugging. It supports breakpoints, register inspection, and flash memory read/write without halting CPU execution - eliminating the need for multi-pin JTAG headers and reducing PCB layout complexity.

Does the STM8S903K3T6CTR support 5 V I/O operation?

Yes, the STM8S903K3T6CTR operates from 2.95 V to 5.5 V and features 5 V-tolerant I/O pins across all ports (PA–PD). This allows direct interfacing with legacy 5 V peripherals such as optocouplers, RS-232 transceivers, and discrete logic without level shifters - verified per DS6210 Section 10.3.6 and Table 40.

How many ADC channels are available and what is their accuracy?

The device provides 7 external analog input channels plus 1 internal reference voltage channel, all accessible through the 10-bit ADC. Accuracy is specified as ±1 LSB integral and differential nonlinearity at VDD = 3.3 V and 5 V, with typical SNR >60 dB - confirmed in DS6210 Tables 47–49 and validated for sensor signal conditioning in industrial temperature ranges.

Is there hardware support for motor control applications?

Yes, the integrated TIM1 advanced control timer provides three complementary PWM outputs with programmable dead-time insertion, synchronization inputs, and fault protection inputs - enabling direct drive of 3-phase inverters or brushed DC motor H-bridges without external gate driver ICs, as detailed in DS6210 Section 4.10 and Figure 1.