Selecting between a SoC, a SOM, and an SBC is a crucial decision in embedded system design. Each offers distinct advantages depending on your application requirements—ranging from industrial control and edge computing to smart gateways and medical devices. This article compares the architectures, features, and design considerations of SoCs, SOMs, and SBCs to help you choose the best solution for your specific project.
What is a SoC?
A System on Chip (SoC) is a single integrated circuit that consolidates all major components of a computing system, including the CPU, GPU, memory controller, and sometimes I/O interfaces, onto a single silicon die. SoCs are the foundation of both SOMs and SBCs, enabling compact, efficient, and high-performance embedded solutions.
SoCs are typically designed for specific application domains such as mobile devices, automotive systems, or industrial control. They offer optimized performance-per-watt ratios and are often tailored with dedicated hardware accelerators for tasks like video decoding or machine learning.
Advantages and Design Considerations of SoCs
- Integration: Reduces the number of external components, saving board space and power.
- Performance Efficiency: Optimized for specific use cases, leading to high efficiency and low latency.
- Cost Savings at Volume: Integration helps reduce BOM (Bill of Materials) costs in high-volume production.
However, designing directly with an SoC requires in-depth knowledge of hardware layout, power domains, and high-speed signal integrity. This complexity is one reason why many developers choose SOMs or SBCs as easier alternatives for leveraging SoC capabilities.
What is a SOM?
A System on Module (SOM) is a compact compute module that includes essential components such as a CPU, RAM, and storage (typically eMMC). SOMs do not include standard connectors like Ethernet ports, USB, HDMI, or power inputs. Instead, they are designed to be integrated into a custom carrier or baseboard, which provides all necessary I/O connectors and peripheral support.
SOMs are primarily used when a modular and scalable architecture is desired. Developers can reuse the same SOM across different product lines, designing custom baseboards to meet the I/O, power, and mechanical needs of each application.
Advantages and Design Considerations of SOMs
Advantages:
- Design Flexibility: A custom baseboard allows precise control over layout, connectors, and functionality, which is ideal for specialized or constrained environments.
- Modular Development: SOMs support reuse across multiple projects or product variants, reducing development time for future designs.
- Optimized BOM Cost at Scale: In large-volume deployments, optimizing the baseboard for a fixed feature set can reduce overall system costs.
Design Considerations:
- Baseboard Engineering: A SOM requires a custom-designed baseboard that supports signal routing, power regulation, and interface circuitry. This process often involves high-speed layout, multi-layer PCB design, and validation.
- Software Adaptation: Developers may need to modify device trees, drivers, or board support packages to match the baseboard’s hardware configuration.
- Team Expertise: Integrating a SOM typically demands both hardware and software engineering capabilities, particularly when working with high-speed interfaces like USB 3.0 or PCIe.
Using reference baseboard designs or development kits provided by SOM vendors can ease the development effort, especially for first-time integration.
Long-Term Availability and Industry Standards for SOMs
SOMs are often designed according to industry standards such as OSM, SMARC, Qseven, and COM Express, which define form factors and interface pinouts. These standards promote interoperability across vendors and help future-proof the design against silicon or component changes.
Many industrial-grade SOM vendors offer long product lifecycles—often 7 to 15 years—ensuring continuity for embedded systems deployed in long-term applications like transportation, energy, and healthcare.
What is an SBC?
A Single Board Computer (SBC) integrates the processor, memory, storage, power circuitry, and standard I/O ports (e.g., USB, HDMI, Ethernet, GPIO) onto a single board. It is a complete, standalone computing platform that is often ready for immediate software development and deployment.
SBCs are frequently used in applications where standard connectivity and fast prototyping are needed. They can be deployed as-is in many industrial and commercial systems, especially when space and hardware requirements align with the SBC’s default configuration.
Advantages and Design Considerations of SBCs
Advantages:
- Ready-to-Use: SBCs offer fast deployment without the need for additional hardware design. This can significantly shorten development time.
- Integrated I/O: All standard peripheral connectors and power interfaces are built-in, enabling direct connection to external systems.
- Prototyping and Low-Volume Production: For smaller production runs or proof-of-concept stages, SBCs can offer a cost-effective and efficient solution.
Design Considerations:
- Fixed Architecture: SBCs may include unused interfaces or features, which could increase power consumption or bill of materials (BOM) cost in some applications.
- Customization Limits: If modifications are required (e.g., additional I/O, alternative connectors), developers must work with the manufacturer for hardware customization or explore board-level redesigns.
- Form Factor Constraints: Since SBCs are pre-defined in size and shape, mechanical integration into custom enclosures or constrained environments may require careful consideration.
Software and Hardware Support for SBCs
Most SBCs ship with a Board Support Package (BSP) that includes a bootloader, kernel, device tree, and root file system. This enables developers to begin software development immediately without needing to configure low-level system components.
Operating system support commonly includes embedded Linux distributions such as Yocto, or Debian, along with pre-configured drivers for interfaces like Ethernet, PCIe, UART, and wireless connectivity. This pre-validated software environment can reduce time spent on debugging hardware integration.
Some vendors also provide tools, documentation, and customization services for specialized use cases, including industrial deployments and performance tuning.
Key Differences: SoC vs SOM vs SBC
| Aspect | SoC (System on Chip) | SOM (System on Module) | SBC (Single Board Computer) |
|---|---|---|---|
| Core Components | CPU + GPU + RAM + I/O interfaces integrated on one chip | CPU, RAM, storage integrated in a compact module | CPU, RAM, storage + all essential I/O on a single board |
| Peripheral Connectors | Requires PCB design to access I/O | I/O exposed via custom-designed baseboard | I/O pre-installed and readily accessible |
| Flexibility | Maximum – hardware fully customized | High – baseboard fully customizable | Fixed – limited to onboard I/O |
| Development Effort | Very high – requires full PCB design and integration | Moderate – only baseboard needs to be developed | Minimal – plug-and-play |
| Scalability | High, but requires design reuse and engineering effort | Easy to scale via interchangeable SOMs | Limited – changes often require full redesign |
| Cost Efficiency | Best for ultra-high volume custom devices | Cost-effective in medium to high-volume applications | Best for prototyping or low-volume projects |
| Customization | Full control over hardware & layout | Flexible customization via baseboard | Limited – depends on available models |
Conclusion
SoCs, SOMs, and SBCs are popular options for embedded systems design. SoC is the foundational silicon layer—ideal for companies with in-house ASIC or hardware development capabilities, aiming for maximum integration and control at the chip level. For most developers, however, SOM and SBC provide more accessible, off-the-shelf solutions.
If your project demands specific hardware integration, long-term scalability, and you have the engineering resources for custom carrier board design, a SOM offers greater flexibility and cost-efficiency in volume production. On the other hand, if you need a ready-to-deploy platform with minimal development effort and faster time-to-market, an SBC provides a complete solution out of the box.
