STM8S105C4T6 - 16MHz 8-Bit MCU with 16KB Flash | STMicroelectronics
MPN: STM8S105C4T6 ✓ ActiveSTM8S105C4T6 Overview
An 8-bit microcontroller is a compact embedded-processing category optimized for control tasks, sensor reading, actuator control, and communication bridging. The STM8S105 belongs to the STM8 access-line hierarchy, combining an 8-bit core with integrated memory and mixed-signal peripherals. Compared with a 32-bit microcontroller, its architecture generally emphasizes lower complexity and efficient deterministic control rather than high-bandwidth computation, making it suitable for cost-sensitive and space-constrained products.
Key features include 16 KB of Flash, 2 KB of RAM, a 16 MHz maximum clock, and a 10-bit ADC. Integrated true data EEPROM allows frequently changed parameters to be stored without consuming all program Flash. The peripheral set includes UART, SPI, and I2C interfaces, supporting serial sensors, external memories, displays, and industrial peripherals. The 48-pin LQFP package provides 38 I/O ports and is suitable for automated PCB assembly and prototype-to-production migration.
The STM8S105 access-line architecture is designed for embedded control applications requiring mixed analog and digital functions. Its 10-bit ADC supports measurements from switches, resistive sensors, and analog control loops, while the serial interfaces reduce external communication-controller requirements. The 2.95 V to 5.5 V supply range accommodates both 3.3 V and 5 V system rails, although the selected external components and operating limits must follow the manufacturer datasheet.
Typical uses include industrial control modules, compact sensor nodes, appliance controllers, building equipment, communication transceivers, and embedded data-acquisition units. The combination of 38 I/O ports, three named serial interface types, timers, and an ADC allows one device to supervise multiple discrete and digital functions while keeping the bill of materials compact.
Designers should preserve the exposed-pad and thermal-layout requirements applicable to the LQFP package, place decoupling capacitors close to the supply pins, and verify unused-pin termination against the datasheet. Firmware replacement is not automatically safe across MCU models because bootloader addresses, peripheral behavior, and interrupt-vector layouts must be checked even when the package dimensions match.
This page consolidates verified manufacturer and distributor information, package and interface details, sourcing links, and replacement guidance for engineers evaluating the STM8S105C4T6. It also distinguishes confirmed electrical differences from compatibility assumptions, helping PCB, firmware, and procurement teams make a controlled decision.
Drop-in alternatives for STM8S105C4T6 — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with STM8S105C4T6 (same form factor and footprint) — differing in Package, ADC Resolution, Architecture, Microcontroller Type, RAM Size.
STM8S103C4T6
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
STM8S105C4T3
✅ Drop-In ⚠️ Specs UnverifiedContact for price
View Datasheet →STM8S105C4T6 Maximum Ratings & Electrical Characteristics
| Microcontroller Type | 8-bit microcontroller |
| Architecture | CISC |
| Maximum Clock Frequency | 16 MHz |
| Flash Program Memory | 16 KB (16K x 8) |
| RAM | 2 KB |
| ADC Resolution | 10 bit |
| Supply Voltage Range | 2.95 V to 5.5 V |
| I/O Port Count | 38 ports |
| Serial Interfaces | UART, SPI, and I2C |
| Package | 48-pin LQFP (LFQP) |
| Mounting Type | Surface mount |
| Delivery Format | Tray |
| Product Line | STM8S access line |
| Lifecycle Status | Active |
STM8S105C4T6 48-pin lqfp (lfqp) Pin Configuration Guide
Pin configuration for STM8S105C4T6 (48-pin lqfp (lfqp) package). This digital IC includes GPIO, communication interfaces (UART, SPI, I2C), and power pins. Refer to the manufacturer datasheet for alternate pin functions and configuration options. Essential for embedded system design and PCB layout.
No detailed pinout data available for STM8S105C4T6.
Refer to the datasheet for full pin configuration.
Typical Applications
STM8S105C4T6 is suitable for 6 applications: Industrial Control Module, Connected Sensor Node, Appliance Controller, Data-Acquisition Front End, Building Equipment Interface, Communication Interface Module.
Industrial Control Module
The STM8S105C4T6 fits compact industrial control modules because it combines a 16 MHz 8-bit core, 38 I/O ports, and integrated timers within a 48-pin LQFP package. Its 10-bit ADC can read resistive inputs, switches, and basic analog sensors, while UART, SPI, and I2C provide paths to operator interfaces, remote transceivers, and expansion devices. A 2.95 V to 5.5 V supply range supports 3.3 V and 5 V control boards. The design advantage is consolidation: one MCU can handle discrete I/O, timing, analog measurement, and serial communication without adding a separate ADC or communications controller. Engineers should preserve the package pin definitions and verify the full operating-temperature and industrial qualification requirements for the deployed environment.
Connected Sensor Node
The STM8S105C4T6 is suitable for a connected sensor node that must sample an analog quantity and communicate with nearby sensors or a host controller. Its 10-bit ADC supports basic process and environmental measurements, while I2C or SPI can connect digital sensors and SPI flash; UART provides a simple diagnostic or telemetry path. The 16 KB Flash is sufficient for a compact access-line control program, and integrated true EEPROM supports nonvolatile configuration or calibration data. At a 16 MHz clock, the device provides responsive peripheral handling without the resource requirements of a larger processor. The key design consideration is balancing the limited 2 KB RAM against acquisition buffering and protocol stack depth.
Appliance Controller
An appliance control board benefits from the STM8S105C4T6's combination of 38 I/O ports, integrated timers, true EEPROM, and multiple serial interfaces. It can supervise relays, keys, displays, heaters, valves, or motors while retaining configuration values in EEPROM and using UART, SPI, or I2C for peripheral expansion. The 48-pin LQFP package provides enough I/O density for a multi-function appliance without occupying a very large board area. Its 2.95 V to 5.5 V operating range also accommodates common appliance rails. Because a switching power environment can introduce conducted and radiated noise, engineers should isolate sensitive ADC inputs, maintain solid grounding, and verify timing margins at the highest line voltage and temperature.
Data-Acquisition Front End
The STM8S105C4T6 can serve as the local controller for a small data-acquisition front end when measurements are primarily analog and data rates are modest. The 10-bit ADC handles sensor conditioning outputs, while timers provide periodic sampling or trigger control and UART or SPI transfers results to a host. Integrated true EEPROM is useful for storing calibration constants and device metadata, reducing the need for external nonvolatile memory. With 16 KB Flash and 2 KB RAM, the MCU is best suited to compact acquisition loops rather than large local data buffers. Designers should budget memory for drivers, apply input filtering according to the source impedance, and isolate analog and digital return paths to improve measurement repeatability.
Building Equipment Interface
The STM8S105C4T6 is applicable to building equipment interfaces that need distributed digital inputs, analog sensing, and serial connectivity. It can monitor switches or sensors, operate outputs through external drivers, and expose status through UART or I2C to a building controller. The 38 available I/O ports reduce the need for separate I/O expanders, while the 10-bit ADC supports simple sensor inputs. Its 2.95 V to 5.5 V supply range allows integration with both 3.3 V and 5 V subsystems found in equipment electronics. For production deployment, the designer must confirm the device's temperature rating, EMC requirements, and any industry-specific certification because those details were not available in the supplied verified records.
Communication Interface Module
The STM8S105C4T6 can support a protocol-conversion or communication-interface module by combining UART, SPI, and I2C with enough general-purpose I/O for indicators, control signals, and configuration. At 16 MHz, the access-line MCU is appropriate for handling byte-oriented or low-complexity serial protocols rather than high-throughput frame processing. The 16 KB Flash supports protocol handlers and application logic, while integrated EEPROM can retain addresses or operating parameters. Designers should select external transceiver levels and timing based on the physical interface, because the MCU logic operating range of 2.95 V to 5.5 V does not itself define RS-485, CAN, or other physical-layer requirements.
Engineering reference data for STM8S105C4T6 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | STM8S103C4T6 | STM8S105C4T3 |
|---|---|---|---|
| Brand | STMicroelectronics | STMicroelectronics | STMicroelectronics |
| Package | 48-pin LQFP (LFQP) | 48-pin LQFP (LFQP) | 48-pin LQFP (LFQP) |
| Core Architecture | 8-bit CISC | 8-bit CISC | 8-bit CISC |
| Maximum Clock Frequency | 16 MHz | 16 MHz | 16 MHz |
| Flash Program Memory | 16 KB | 16 KB | 16 KB |
| ADC Resolution | 10 bit | 10 bit | 10 bit |
| Serial Interfaces | UART, SPI, and I2C | UART, SPI, and I2C | UART, SPI, and I2C |
| I/O Port Count | 38 ports | 38 ports | 38 ports |
Key Differentiators
- Access-line integration with three named serial interfaces (vs STM8S103C4T6)
- Direct ordering-format retention of the exact device configuration (vs STM8S103C4T6)
- High I/O density for a compact access-line controller (vs STM8S105C4T3)
Design Notes
Place the required input and output decoupling capacitors directly beside the corresponding STM8S105C4T6 supply pins, with short and low-inductance return paths to the ground plane. The device operates from 2.95 V to 5.5 V, but capacitor voltage and tolerance must accommodate the actual rail, transient margin, and regulator behavior. Preserve the manufacturer-recommended 48-pin LQFP copper geometry and thermal-relief pattern to avoid assembly defects and unnecessary temperature rise.
Keep analog inputs connected to the 10-bit ADC away from UART, SPI, and I2C switching nodes, particularly when clocks or high-current outputs are nearby. Use a continuous ground reference beneath analog routing, keep sensor returns separate from power-return currents, and place input filtering close to the ADC source. If a sensor output has high source impedance, include sufficient settling time and capacitance for the ADC acquisition network without overloading the input.
Do not substitute an MCU solely because it uses a 48-pin LQFP. Before replacing STM8S105C4T6, compare the complete pin map, alternate functions, clock limits, memory map, bootloader address, interrupt vectors, peripheral registers, and errata. The STM8S103C4T6 candidate retains the verified 16 MHz and 16 KB Flash figures but still requires peripheral-level review. An ordering-suffix change such as STM8S105C4T3 is lower risk electrically, but firmware and delivery requirements must still be confirmed.
Design the supply path for the full 2.95 V to 5.5 V operating range and account for startup, reset, and peripheral-load transients rather than only nominal current. The retrieved records do not provide detailed current consumption, so quiescent and active-current budgets must be taken from the manufacturer datasheet. Use local bulk capacitance where supply impedance permits, and validate the rail with an oscilloscope during startup and worst-case peripheral activity.
Compliance Information
The verified snippets identify the part as active but do not provide explicit RoHS, REACH, AEC-Q100, lead-free, halogen-free, or conflict-minerals statements. These values remain unknown rather than being inferred. The official STMicroelectronics product page and datasheet should be checked for the latest declarations.
