STM8S003F3U6TR vs STM8S003F3P6TR: Package and MCU Differences

ElecSuppliers Part Number ComparisonAug 22, 2026

STM8S003F3U6TR and STM8S003F3P6TR are two closely related members of the STM8S003F3 microcontroller family. Both are designed for general-purpose embedded control and share the same basic STM8 architecture and core feature set.

The most important difference for engineers working on a PCB is the package. STM8S003F3U6TR uses a compact UFQFPN-20 package, while STM8S003F3P6TR is available in a TSSOP-20 package.

This difference can have a major impact when selecting a component for a new PCB or looking for a replacement for an existing design.

STM8S003F3U6TR Package

STM8S003F3U6TR uses a 20-pin UFQFPN package with a compact footprint.

The small package is useful when PCB area is limited. It can be a good fit for compact control boards, consumer electronics, embedded modules and other products where reducing component size is important.

However, the smaller package also requires more precise PCB layout and assembly processes. Soldering, inspection and manual rework can be more demanding compared with a leaded package.

For high-density PCB designs, the compact package can provide a significant space advantage.

STM8S003F3P6TR Package

STM8S003F3P6TR uses a 20-pin TSSOP package.

TSSOP provides visible leads along the sides of the package, making the device relatively convenient for PCB inspection and rework.

The package occupies more board space than the compact UFQFPN version, but it can be easier to handle during prototype development and production assembly.

For industrial control boards and products where PCB space is less restrictive, TSSOP-20 can be a practical choice.

STM8S003F3U6TR and STM8S003F3P6TR Specifications

Both devices are based on the STM8S003F3 platform and provide similar core resources.

The main specifications include an STM8 8-bit CPU operating at up to 16 MHz, 8 KB Flash program memory, 1 KB RAM and 128 bytes of data EEPROM.

The MCU family also integrates a 10-bit ADC, timers and commonly used communication interfaces including UART, SPI and I²C.

This makes both devices suitable for applications that require embedded processing, analog signal measurement, timing control and communication with external components.

Can STM8S003F3U6TR Replace STM8S003F3P6TR?

Not as a simple physical drop-in replacement.

Although the two devices belong to the same MCU family and have closely related electrical characteristics, the package construction and PCB footprint are different.

A PCB designed for TSSOP-20 cannot simply accept the UFQFPN version without changing the board layout.

The same applies in the opposite direction.

Therefore, if an existing product uses STM8S003F3P6TR, changing to STM8S003F3U6TR normally requires a PCB revision.

The firmware migration can be much simpler because the devices share the same basic MCU family, but the actual pin mapping and peripheral configuration should still be checked carefully.

STM8S003F3U6TR for Compact PCB Designs

STM8S003F3U6TR is particularly attractive when board space is a major design constraint.

A smaller MCU package can leave additional PCB area for connectors, sensors, power components or other functional circuits.

This can be important in compact controllers, portable electronics and small embedded modules.

The trade-off is that a smaller package places greater demands on PCB manufacturing and assembly.

For mass-produced products with a mature SMT manufacturing process, this may not be a major issue. For prototypes or low-volume products, the TSSOP version may be easier to work with.

STM8S003F3P6TR for Easier Assembly

STM8S003F3P6TR can be advantageous when assembly accessibility is more important than minimizing the MCU footprint.

The TSSOP package provides external leads that are easier to visually inspect than a leadless package.

This can simplify prototype assembly, troubleshooting and manual rework.

For engineering teams developing a new controller board, package selection should therefore consider not only PCB area but also manufacturing capability and maintenance requirements.

STM8S003F3 Family Applications

Both package versions can be used in similar categories of embedded applications.

Typical uses include appliance controllers, LED control, sensor interfaces, industrial control boards, small automation equipment, power-management circuits and consumer electronics.

The integrated ADC can be used for analog sensor measurements, while timers and PWM can handle timing and output-control functions.

UART, SPI and I²C allow the MCU to communicate with external modules and peripheral ICs.

STM8S003F3U6TR Selection Considerations

STM8S003F3U6TR is a good candidate when the priority is a compact PCB design.

Before selecting it, designers should check the available PCB assembly process, package footprint, pin assignment and thermal characteristics.

The smaller package should also be considered during prototype development because manual soldering and inspection can be more difficult.

If the product requires a very small controller board and automated SMT assembly is already available, the UFQFPN version can be an efficient solution.

STM8S003F3P6TR Selection Considerations

STM8S003F3P6TR is worth considering when a leaded package is preferred.

Its TSSOP package can simplify inspection and rework while still providing a relatively compact surface-mount solution.

This can be useful during product development, engineering prototypes and applications where board space is not the primary constraint.

STM8S003F3U6TR vs STM8S003F3P6TR: Which One to Choose?

The decision largely depends on the PCB and manufacturing requirements.

Choose STM8S003F3U6TR when compact board dimensions and component density are important.

Choose STM8S003F3P6TR when easier inspection, prototyping and manual rework are more important.

For firmware and system functionality, the two devices are closely related, so the package should be one of the first differences considered during component selection.

STM8S003F3U6TR in New Designs

STM8S003F3U6TR remains a practical option for embedded products that need a small 8-bit MCU with integrated memory, timers, ADC and communication interfaces.

Its compact package can help reduce PCB size without moving to a more complex microcontroller architecture.

For engineers selecting between STM8S003F3U6TR and STM8S003F3P6TR, the key question is not simply which MCU has better specifications. Both belong to the same STM8S003F3 platform, so the more important decision is whether the design prioritizes compact PCB dimensions or easier assembly and rework.