STM8S003F3M6TR vs STM8S003F3K6T6: Choosing the Right STM8 MCU

ElecSuppliers Part Number ComparisonAug 22, 2026

STM8S003F3M6TR and STM8S003F3K6T6 belong to the same STM8S003F3 microcontroller family. Their core architecture and main memory resources are closely related, so the distinction between the two is more useful to engineers when viewed from the perspective of package, ordering code and PCB design.

When selecting one of these devices for a new project, it is therefore important to look beyond the shared STM8S003F3 designation and examine the complete part number.

STM8S003F3M6TR and STM8S003F3K6T6 Core Resources

Both part numbers are based on the STM8 8-bit MCU architecture and operate at up to 16 MHz.

The STM8S003F3 platform provides 8KB Flash memory, 1KB RAM and 128 bytes of data EEPROM.

The integrated peripherals include a 10-bit ADC, timers and serial communication interfaces such as UART, SPI and I²C.

This makes the family suitable for small embedded control systems that need a combination of digital I/O, analog measurement and hardware timing.

Because the underlying MCU resources are similar, the key selection question is often not processing capability but whether the particular ordering code matches the intended hardware.

Why the Complete Part Number Matters

The final characters in an MCU ordering code can identify important production information, including package and delivery configuration.

This becomes particularly important when purchasing components for an existing PCB.

A device with similar memory and peripheral resources may not be a direct replacement if the package or pin arrangement is different.

For this reason, STM8S003F3M6TR and STM8S003F3K6T6 should not be treated as interchangeable simply because they belong to the same MCU family.

The exact manufacturer part-number information should always be checked before a component is approved for production.

STM8S003F3M6TR for Embedded Control

STM8S003F3M6TR can be used in compact control systems where an 8-bit MCU provides enough processing capability.

Typical tasks include reading switches, monitoring sensors, controlling LEDs, generating PWM signals and communicating with peripheral ICs.

The ADC can handle analog measurements, while timers can provide periodic interrupts and PWM outputs.

This combination is useful in products where the MCU needs to perform several straightforward control tasks simultaneously.

STM8S003F3K6T6 in Control Applications

STM8S003F3K6T6 is also positioned for general-purpose embedded control.

The same basic STM8S003F3 resources make it suitable for appliance controllers, sensor modules, small automation systems and consumer electronics.

A typical design might use GPIO for buttons and indicators, ADC for sensor measurements, timers for PWM and UART or I²C for communication.

For these applications, the MCU's integrated peripherals can reduce the number of external components required on the PCB.

Memory Requirements

The 8KB Flash capacity of the STM8S003F3 family is intended for relatively compact firmware.

It can be used for control algorithms, peripheral drivers, communication routines and basic data processing.

The 1KB RAM provides working space for application variables, stack operations and communication buffers.

The integrated EEPROM can retain configuration information after power loss.

When comparing STM8S003F3M6TR and STM8S003F3K6T6, engineers should therefore evaluate whether the existing firmware actually fits within these resources rather than choosing a device solely on the basis of CPU speed.

ADC and Sensor Applications

The integrated 10-bit ADC makes the STM8S003F3 family useful for simple sensor systems.

An MCU can periodically sample an analog signal, process the measurement and activate an output when a predefined condition is reached.

Potential inputs include temperature-related sensors, voltage-monitoring circuits, potentiometers and other analog sources.

For a sensor controller, the ADC configuration and available channels may be more important than the difference between two similar ordering codes.

Timer and PWM Requirements

Timer resources should be reviewed when replacing or comparing MCU variants.

Timers can be used for periodic interrupts, pulse measurement and PWM.

PWM can control LEDs, fans and external motor-driver circuits.

If the existing firmware depends on specific timer channels, the exact pin assignment should be checked before changing to another device.

A replacement MCU may provide similar timer functionality but place the corresponding output on a different pin.

Package and PCB Compatibility

Package compatibility is one of the most important considerations when choosing between different STM8S003F3 ordering codes.

For a new PCB, designers can select the package that best fits their assembly process and board-space requirements.

For an existing PCB, the package footprint must match the board.

This is particularly important when sourcing alternative STM8S003F3 devices. Similar electrical specifications do not guarantee mechanical compatibility.

Before approving a replacement, engineers should compare the package drawing, pin numbering and PCB land pattern.

How to Choose Between the Two

For a new design, the choice should start with the required MCU functions.

If the application needs 8KB Flash, 1KB RAM, ADC, timers and standard serial interfaces, the STM8S003F3 family provides a suitable starting point.

The next step is to select the exact ordering code according to package and production requirements.

For an existing design, the process is different. The original PCB footprint, firmware and peripheral assignments should be checked first. Only after these are confirmed should another ordering code be considered.

STM8S003F3M6TR and STM8S003F3K6T6 Replacement Strategy

When component availability becomes an issue, staying within the same MCU family can sometimes simplify migration.

The shared STM8 architecture can reduce the software changes compared with moving to an unrelated MCU family.

However, engineers should still verify the exact hardware configuration.

The replacement process should include firmware review, pin mapping, package verification, peripheral testing and production validation.

A device should not be classified as a direct replacement simply because its part number starts with the same STM8S003F3 prefix.

Practical Selection for Production

For mass production, component selection should consider more than the initial electrical specification.

Package availability, assembly capability, supplier consistency and long-term sourcing can all affect the final decision.

A package that is ideal for a compact PCB may not be the best option for a manufacturing line designed around a different footprint.

Similarly, a replacement that works electrically may still require PCB changes that increase development time.

Choosing an STM8S003F3 Variant

STM8S003F3M6TR and STM8S003F3K6T6 are best evaluated as specific ordering codes rather than simply as two names within the same MCU family.

Their shared STM8S003F3 architecture provides a similar foundation for embedded control, but the exact package and ordering information must be verified for the intended application.

For a new project, select the variant according to the PCB, assembly and firmware requirements. For an existing product, prioritize pin compatibility, package compatibility and software migration requirements before considering the device suitable for replacement.