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Diving into the World of System-on-Modules: Form Factors and Feature Feast

System-on-Modules (SoMs) are the tiny workhorses of the embedded systems world. These compact, pre-built packages integrate core processing components like processors, memory, and communication interfaces onto a single board. But within this seemingly simple concept lies a world of variety, particularly in terms of form factors and the features they can pack. Let’s delve into the different ways SoMs are shaped up and explore the extra functionalities they might bring to the table.

The Feature Feast: Beyond the Core

While the core processing components are essential, SoMs can offer a plethora of additional features that enhance their capabilities:

  • Power Management Integrated Circuits (PMICs): These on-board chips regulate power delivery to the SoM, ensuring efficient and stable operation. The more advanced PMICs feature a large number of power sources that can be controlled independently. The best of them implement dynamic power scaling: they finely adjust the voltage delivered to the CPU based on its power demand in real-time.

  • Wireless Connectivity: Wi-Fi and Bluetooth chips embedded within the SoM eliminate the need for separate components, simplifying design, reducing board space and facilitating certification.

  • Sensors: Some SoMs integrate environmental sensors that help adjust the operation of the core. Typical sensors include temperature monitors and power consumption probes.

  • Additional Memory: Beyond the core RAM and storage, SoMs might include options for different types of memory like configuration EEPROMs or a limited amount of NOR Flash.

Form Factor Frenzy: Choosing the Right Fit

The form factor of an SoM refers to its physical size, shape, and connection method. Here are the main contenders:

  • Stamp Hole: Also called castellated edge, this low-profile option uses standard soldering techniques to integrate the SoM directly onto the main Printed Circuit Board (PCBA). Think of it as a tiny, pre-built chip that gets permanently attached during the PCBA manufacturing process.

  • Edge Connectors: These SoMs, often utilizing industry standards like MXM3 or SMARC, feature a connector on one edge. This allows for easier integration and potential replacement or upgrade down the line. Think of it like a modular cartridge system for your embedded device.

  • High-density Interconnects (HDI): Packing the most punch in terms of pin count and functionality, HDI connectors offer superior signal integrity and support for high-speed interfaces. However, they come in various densities and levels of quality, with higher quality options featuring better pairing and impedance control for critical applications. Imagine these as high-performance docking ports for your SoM, offering maximum data throughput and control.

Choosing the Right SoM: A Balancing Act

The ideal SoM form factor and feature set depend heavily on your specific application. Here are some key considerations that go beyond the selection of the CPU horsepower and memory capacity:

  • Size Constraints: If space is at a premium, a stamp hole or a SoM fitted with a low-profile HDI on the bottom side might be ideal.

  • Upgradeability: Opt for edge connectors if future upgrades or replacements are a possibility. This type of connectivity is often sensitive to vibration and dust. Make sure to select a socket of appropriate quality, and consider securing the assembly with screws.

  • Performance Needs: HDI connectors become attractive for high-speed data applications where signal integrity is a must.

  • Power Consumption: The presence of a PMIC can be crucial for battery-powered devices.

  • Connectivity Demands: If your project requires wireless capabilities, look for SoMs with integrated modules. They’ll save a lot of efforts, especially in the context of wireless integration.

  • Pre-Certification: Any electronic product requires some sort of certification, be it CE, FCC, UL, etc. Always favor a SoM that comes with a solid pre-certification documentation, especially if wireless connectivity is expected. It will streamline the certification process and save endless headaches.

By understanding the different form factors and available features, you can select the perfect SoM for your project, ensuring a powerful, compact, and feature-rich embedded system solution.

At Embedded Expertise we have a comprehensive view of the global commercial SoM offering. We also distribute a number of SoMs with distinctive features from a short list of vendors. Should you need assistance in selecting your ideal module, please contact us with your project requirements and we’ll be happy to provide guidance.

Dusun IoT DSOM-010R SoM
Credit: Dusun IoT