STMicroelectronics STM8S105K4U3ATR

Overview

STM8S105K4U3ATR from STMicroelectronics is an 8-bit access-line microcontroller featuring a 16 MHz STM8 core, 16 KB Flash, 1 KB data EEPROM, 10-bit ADC with 10 channels, UART/SPI/I²C interfaces, and advanced timers including TIM1 with dead-time insertion - deployed in industrial motor control feedback loops, smart sensor nodes, and appliance power management subsystems.

For engineers reviewing the STM8S105K4U3ATR datasheet, STM8S105K4U3ATR pinout, STM8S105K4U3ATR application, or STM8S105K4U3ATR equivalent, key selection criteria include Flash retention (20 years @ 55 °C), EEPROM endurance (300 kcycle), low-power modes (halt/active-halt/wait), 16 MHz RC oscillator trimmability, and LQFP48 package compatibility with legacy STM8S footprint designs.

Technical Context

The STM8S105K4U3ATR implements a Harvard-architecture 8-bit core with 3-stage pipeline and extended instruction set, supporting nested interrupts across 32 vectors and up to 37 external interrupt sources mapped to 6 priority levels. Its clock system integrates four independent sources: user-trimmable 16 MHz RC, 128 kHz low-power RC, crystal resonator, and external clock input - all monitored by a clock security system.

Analog and timing subsystems include a 10-bit ±1 LSB ADC with scan mode and analog watchdog, TIM1 (16-bit advanced timer with 3 complementary outputs and dead-time control), two 16-bit general-purpose timers (TIM2/TIM3), and an 8-bit basic timer (TIM4) - enabling precise PWM generation, motor phase control, and synchronous serial communication timing.

Key Specifications

Pinout & Package

LQFP48 (7 × 7 mm, 0.5 mm pitch) package with 48 leads; thermally enhanced exposed pad for improved heat dissipation in continuous operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STM8S105K4U3ATR, the K4T3CTR retains full peripheral compatibility in smaller footprint but loses I/O count and TIM1 capabilities, while the S003F3P6TR cuts Flash, EEPROM, and timer depth significantly - making it unsuitable for applications requiring robust analog acquisition or multi-phase timing.

Availability

STM8S105K4U3ATR is available at Aetrix Electronics and suitable for industrial motor control, smart appliance subsystems, wireless sensor edge processing, and PLC I/O expansion modules requiring stable component supply across multi-year production cycles.

Supply support for STM8S105K4U3ATR 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-sensitive, high-reliability 8-bit embedded applications - emphasizing Flash retention, EEPROM endurance, low-power operation, and robust I/O for industrial automation and white goods control.

FAQ

What is the maximum operating frequency and corresponding voltage range for STM8S105K4U3ATR?

The STM8S105K4U3ATR operates up to 16 MHz across its full supply range of 2.95 V to 5.5 V. At 3.3 V, it sustains 16 MHz reliably per datasheet Figure 11; at 2.95 V, maximum frequency is derated to ~14 MHz. This voltage-frequency relationship is guaranteed by ST's characterization and validated in production testing per DS5855 Rev 16 Section 10.3.1.

Does STM8S105K4U3ATR support in-system programming via SWIM, and what hardware is required?

Yes, STM8S105K4U3ATR supports full in-system programming and debugging via the Single-Wire Interface Module (SWIM) on PB4. Required hardware includes an ST-LINK/V2 or compatible debugger, 5-pin SWIM connector (VDD, VSS, SWIM, NRST, SWIM_CLK), and proper decoupling. No bootloader is needed - the SWIM interface is hardwired into the silicon and active immediately after power-on.

How many I/O pins support high-sink capability, and what is the rated current per pin?

16 I/O pins (PA0–PA7, PB0–PB7, PC0–PC7, PD0–PD7, PE0–PE7 - specific subset defined in datasheet Table 5) support high-sink output with 20 mA DC current rating per pin at VDD = 5 V and TA = 25 °C. Total sink current across all high-sink pins must not exceed 80 mA (DS5855 Rev 16 Section 10.3.6), and thermal derating applies above 70 °C ambient.

Is the internal 16 MHz RC oscillator factory-calibrated, and can it be re-trimmed in the field?

The internal 16 MHz RC oscillator is factory-trimmed to ±1% accuracy at 25 °C and stored in option bytes. Users can re-trim it in-field via the CLK_HSITRIMR register (address 0x50C0) using a known reference clock (e.g., from UART or external crystal) - enabling compensation for temperature drift or aging, with resolution of ±1.5% over full range per Section 4.5 and Table 33 of DS5855 Rev 16.