System on Chip: An Engineer’s Guide to Design and Selection

Choosing to build your product around a System on Chip (SoC) is a high-stakes architectural decision with massive downstream consequences. An SoC integrates the CPU, GPU, memory controllers, and peripherals onto a single piece of silicon, promising lower BOM costs, a smaller footprint, and better power efficiency. However, get this decision wrong, and you risk catastrophic schedule slips, bloated NRE costs, and a product that's impossible to manufacture at scale.

This guide is for the CTOs, VPs of Engineering, and lead engineers responsible for delivering complex hardware on time and on budget. It’s for teams navigating the trade-offs between a custom SoC design, a microcontroller, and a System-on-Module (SoM). This is not a guide for hobbyists or projects where a few discrete components will suffice. We frame the SoC decision as a critical risk management exercise, balancing integration benefits against significant hardware, firmware, and manufacturing challenges.

By the end of this guide, you will be able to:

• Evaluate an SoC vs. a SoM based on production volume, time-to-market, and team expertise.
• Identify critical board-level risks like power integrity and signal integrity early in the design phase.
• Structure a bring-up plan to systematically debug a "dead" SoC board and avoid common failure modes.

Why a System on Chip Strategy Matters Now

Adopting an SoC architecture is a business decision disguised as a technical one. While lower BOM cost and a smaller product footprint are the most visible benefits, the real impact cascades through power consumption, performance, supply chain complexity, and manufacturing yield. The wrong choice can lock you into a cost structure or development timeline that makes your product uncompetitive before it even launches.

Market trends confirm the stakes. The global System on Chip market was valued at around USD 184.53 billion in 2025 and is projected to reach USD 385.17 billion by 2034, growing at a CAGR of 8.62%. This growth is driven by the relentless demand for compact, power-efficient smart devices. As data from Precedence Research shows, mastering SoC-based design is no longer an advantage; it's a competitive necessity.

A classic failure mode is underestimating firmware and hardware integration complexity. Teams accustomed to simpler MCUs are often blindsided by SoC bring-up. The process demands a much higher level of engineering discipline, particularly around power management, clocking, and high-speed memory interfaces. A single misconfigured pinmux or an unstable power rail can render a board completely unresponsive.

This complexity is why high-performing teams insist on a unified ownership model, where hardware and firmware are co-developed, not handed off over a wall. For a deeper look at this integrated approach, our guide on the fundamentals of embedded systems engineering is a valuable resource. Ultimately, committing to an SoC defines your entire product development lifecycle, from initial architecture to the production line.

Choosing Your Integration Strategy: SoC vs. SoM

The first and most critical architectural decision is selecting the right level of integration. This isn’t about finding the "best" technology; it’s about aligning the technical approach with your program’s specific constraints: timeline, budget, team expertise, and projected production volume. Getting this wrong introduces massive downstream risk, from blowing your NRE budget to launching a product that’s not cost-competitive at scale.

A full custom board design using a System on Chip (SoC) offers the highest integration, enabling maximum performance in the smallest footprint. However, this path requires significant non-recurring engineering (NRE) investment, deep expertise in high-speed digital design, and a longer development timeline. It’s a strategy that delivers huge BOM cost savings at high manufacturing volumes but can be financially ruinous for a new product’s initial ramp.

A Microcontroller (MCU) sits at the other end of the spectrum. MCUs are simpler, cheaper, and much faster to design with, making them ideal for less computationally intensive tasks. Their limited processing power and peripheral sets make them a non-starter for applications requiring a full OS, real-time video processing, or complex AI/ML workloads.

The Pragmatic Middle Ground: System on Module (SoM)

This is where the System on Module (SoM) provides a compelling and often strategic compromise. A SoM is a small, pre-validated circuit board containing the most complex parts of the system: the SoC, DRAM, and power management ICs (PMICs).

By using a pre-certified SoM, your team sidesteps the most difficult and error-prone aspects of hardware design, such as routing high-speed DDR memory traces. Instead, you focus on designing a simpler, custom "carrier" board that hosts your application-specific connectors and peripherals. This approach dramatically de-risks the hardware development schedule. The trade-off is a higher per-unit cost compared to a custom SoC design and less control over the final form factor.

This is a classic engineering trade-off. A SoM accelerates time-to-market with lower technical risk, making it ideal for the EVT/DVT phases and initial production runs. A custom SoC design minimizes per-unit cost at scale but pulls in significant schedule and NRE risk upfront. High-performing teams often prototype with a SoM to de-risk firmware development before committing capital to a full custom design for mass production.

A Decision Framework for Your Architecture

To make an informed choice, you must weigh technical requirements against business realities. An industrial robotics firm building 500 autonomous navigators has vastly different constraints than a consumer electronics company shipping 500,000 smart home hubs.

Here are the primary decision criteria:

• Production Volume & BOM Cost: At volumes below 10,000-20,000 units/year, the NRE of a custom SoC design is rarely justifiable. The higher per-unit cost of a SoM is easily offset by the savings in development time and engineering resources.
• Time-to-Market: If speed is the primary driver, a SoM is almost always the faster path. It can eliminate months of complex PCB design, layout, and validation for the core processing subsystem.
• Team Expertise: A custom SoC design requires specialized skills in high-speed digital design, power integrity, and signal integrity analysis. If your team lacks this deep expertise, a SoM is a much safer, more predictable path.
• Form Factor & Customization: For products with extreme size or shape constraints—such as a compact wearable or drone—a custom SoC layout provides maximum design flexibility. SoMs, while small, have fixed dimensions that may not fit every unique enclosure.

This flowchart maps the decision to its most common driver: production volume.

The flowchart highlights a core principle: for high-volume products where every cent on the BOM matters, the upfront NRE of a custom SoC design is a calculated investment. For most other scenarios, the risk reduction and accelerated timeline offered by a SoM are strategically superior.

Navigating Critical SoC Design and Verification Tradeoffs

Choosing an SoC simplifies your BOM but dramatically increases board-level design complexity. The sheer density of functionality creates challenges in power distribution, signal integrity, and thermal management that are far less severe in simpler MCU-based designs. Getting this phase wrong is the most common cause of costly board re-spins, schedule slips, and catastrophic field failures.

This is where a single-threaded technical ownership model is essential. When hardware and firmware teams operate in silos, the handoff becomes a major point of failure. High-performing teams ensure these disciplines collaborate from day one, jointly owning the bring-up plan and de-risking the entire system before a single PCB is fabricated.

Core Hardware Design Challenges

Migrating to an SoC forces a higher level of engineering discipline, especially in three key areas. Underestimating any one of them risks derailing your program.

• Power Integrity: An SoC is not a single 3.3V component. It is a complex system with a dozen or more power domains for different cores, memory interfaces, and peripherals. Delivering clean, stable power to each requires a meticulously designed Power Delivery Network (PDN). Noise on a core voltage rail can lead to intermittent crashes that are nearly impossible to debug.
• Signal Integrity: High-speed interfaces like DDR memory, MIPI, PCIe, and Ethernet are unforgiving. Signal integrity issues, such as impedance mismatches or excessive crosstalk, lead to corrupted data and intermittent failures that are maddeningly difficult to reproduce and diagnose post-fabrication.
• Thermal Management: Concentrating so much processing power in a small area generates significant heat. If thermal design is an afterthought, you risk performance throttling at best and permanent component damage at worst.

These challenges are intensifying as market demand for powerful, integrated solutions grows. Digital SoCs are expected to command a 52.45% revenue share in 2025, a trend driven by the use of reusable IP to accelerate product development. The overall SoC market is projected to grow from USD 161.88 billion in 2025 to USD 249.19 billion by 2031, with automotive SoCs showing a massive 13.85% CAGR. You can explore these SoC market trends to understand the evolving landscape.

Designing for Testability Is Non-Negotiable

On a complex SoC with BGA packaging, you cannot simply probe a pin to diagnose a problem. If you have not designed for testability (DFT) from the outset, you are flying blind during bring-up and manufacturing. A robust verification and test strategy is your only defense against late-stage disasters.

A classic failure mode is treating DFT as a "nice-to-have." We've seen teams finalize a layout to meet form-factor goals, only to discover they have no way to program the SoC on the production line or diagnose why a board won't boot. Testability must be a primary design requirement, on par with performance and power.

Your DFT strategy must include several core elements:

1. Strategic Test Points: Critical signals—power rails, clocks, and reset lines—must be accessible for probing during debug.
2. JTAG/Boundary Scan: This is the backbone of board-level manufacturing test. It allows you to verify pin-level connectivity and detect manufacturing defects like solder shorts or open circuits without needing the full system to boot.
3. Manufacturing Firmware: A dedicated firmware image, developed in parallel with the main application, is essential. Its sole purpose is to exercise all I/O and peripherals for automated testing on the production line, providing high-confidence validation that each unit is assembled correctly.

Cutting corners on DFT doesn't save time; it merely defers risk to a stage where it becomes exponentially more expensive to fix. A well-planned test strategy is one of the highest-leverage investments you can make to ensure a smooth transition from prototype to production.

Mastering SoC Firmware Bring-Up and Validation

A perfectly designed board is an expensive paperweight until firmware brings it to life. For most complex product programs, the initial firmware bring-up of an SoC is the single greatest point of schedule risk. This is where meticulous hardware design meets the unforgiving reality of software execution.

The process is a delicate, multi-stage sequence. A typical boot chain starts with the Boot ROM (code fused into the silicon), which loads a Second Program Loader (SPL) from flash. The SPL initializes critical hardware like DRAM before handing off to a more capable bootloader like U-Boot. Finally, U-Boot loads the full operating system kernel. A failure at any point in this chain results in the same symptom: a "dead" board. The art of bring-up is turning this crisis into a systematic debugging process.

Troubleshooting a 'Dead' SoC Board

When a new board fails to boot, a structured, methodical approach is essential. The immediate goal is to find the first sign of life, typically output from the SoC’s serial debug port (UART). If the UART is silent, it's time to work backward from software into the hardware domain.

Here are the most common failure modes and the first diagnostic steps:

• Power Rails: Are all voltage rails stable and at their correct levels? An SoC can have a dozen or more. Use an oscilloscope to check for noise and verify they are sequencing correctly.
• Clock Signals: Is the primary crystal oscillator running? Without a stable clock, the SoC is truly inert. Probe the oscillator output.
• Reset Line: Is the reset line stuck in its active state (e.g., stuck low)? A stuck reset will prevent the CPU from ever starting its boot sequence.
• Memory Timing: Incorrect DRAM timing parameters are an extremely common cause of boot hangs after the SPL. This often requires a JTAG debugger to halt the CPU and inspect memory controller registers directly.

A "dead" board rarely indicates a faulty SoC. Over 90% of the time, the root cause is a subtle issue with power, clocks, memory configuration, or an incorrect peripheral pinmux setting. The key is to have the right tools—JTAG debugger, logic analyzer, oscilloscope—and a plan to isolate variables systematically.

This diagnostic checklist provides a clear starting point when the pressure is on.

Common SoC Bring-Up Failure Modes and Diagnostic Steps

A systematic approach like this transforms a frustrating black-box problem into a solvable engineering challenge.

Building a High-Reliability Firmware Infrastructure

Booting the board is just the first milestone. For a product to succeed in the field, its firmware must be robust, secure, and serviceable. High-performing teams build this reliability on three pillars.

1. Fault Recovery Mechanisms: No software is perfect. Implement hardware watchdogs to automatically reset the system if the main application freezes. Brown-out detection is also critical to ensure predictable SoC behavior during power fluctuations.
2. Secure Over-the-Air (OTA) Updates: The ability to update firmware in the field is non-negotiable for deploying features and patching security vulnerabilities. A robust OTA mechanism requires secure boot to verify image authenticity, A/B partitioning for fail-safe updates, and a proven rollback capability.
3. Actionable Telemetry and Logging: When a device fails in the field, data is essential. Instrumenting firmware to log critical events, system states, and fault conditions to non-volatile memory is critical for remote diagnosis and rapid root-cause analysis.

This infrastructure directly impacts business outcomes by reducing costly service calls, protecting customers from security threats, and enabling continuous improvement post-launch. For teams implementing these capabilities, our overview of embedded firmware development services provides a deeper look into these high-reliability patterns.

Making It Real: How to Design for Manufacturing and Scale with SoCs

Achieving a working prototype is a critical milestone, but it is not the finish line. The transition from a single Engineering Validation Test (EVT) board to a reliably manufacturable product is where many programs falter. Early-stage decisions on Design for Manufacturing (DFM) and Design for Testability (DFT) will define your final cost, production yield, and long-term product quality.

Ignoring DFM/DFT is a common and expensive mistake. Teams often defer manufacturing concerns, treating them as a "later" problem. That "later" inevitably arrives as costly board re-spins, schedule-crushing delays, and abysmal initial production yields that can sink a product launch. High-performing teams embed manufacturing readiness into their design process from day one.

The BGA Problem and PCB Complexity

Most SoCs use Ball Grid Array (BGA) packages to accommodate a high number of I/O connections in a small footprint. This density creates significant challenges for your Printed Circuit Board (PCB) layout, directly impacting board cost and reliability.

Key considerations include:

• Escape Routing: Planning how traces will "escape" the dense grid of solder balls under the BGA is a complex puzzle that often determines the required number of PCB layers—a primary driver of cost.
• Via-in-Pad (VIP): For the tightest BGA packages, placing vias directly on the BGA solder pads may be necessary. While this saves space, it adds cost and complexity to the fabrication process and requires close collaboration with your PCB vendor to ensure reliability.

You Can't Ship What You Can't Test

A comprehensive manufacturing test plan is your last line of defense against shipping defective units. It is a detailed strategy to verify that every board coming off the assembly line is free of defects and functions as intended.

For a complex system on chip design, a multi-stage test plan is non-negotiable:

1. Fixture Design: Custom test fixtures (often called a "bed of nails") are required to make precise, automated contact with test points on the board.
2. In-Circuit Testing (ICT): This stage uses the fixture to check for basic assembly defects like short circuits, open connections, or incorrect component placement.
3. Boundary Scan (JTAG): This powerful technique verifies the integrity of solder connections on complex components like the SoC, confirming that every BGA ball is properly connected without needing to boot the system.
4. Secure Provisioning: The plan must detail how each unit is securely programmed with firmware, unique serial numbers, and cryptographic keys on the factory floor to prevent counterfeiting and protect intellectual property.

To learn more about these concepts, our guide on what Design for Manufacturing entails is an excellent resource.

Case Study: Rescuing a Disastrous Industrial Controller Yield

An industrial automation client was preparing to ramp production of a new SoC-based motor controller. Their engineering builds performed flawlessly, but the first pilot production run hit a wall: an 85% factory yield. Fifteen out of every hundred boards were failing, a catastrophic rate for a mass-produced product.

The low yield was inflating their per-unit cost and jeopardizing a major product launch. The failures were inconsistent—some boards were dead, others had intermittent communication issues.

By implementing a rigorous Failure Reporting, Analysis, and Corrective Action System (FRACAS), the team systematically root-caused the failures. They discovered that 60% of the fallout was due to a subtle power-on sequencing issue that only manifested on a small percentage of boards. Another 30% was traced to a marginal batch of flash memory components.

With the root causes identified, the fixes were targeted. A firmware update adjusted the power-on timing, eliminating the sequencing bug. Simultaneously, they tightened incoming quality inspection for flash memory and qualified a second source. Within two production runs, the yield climbed from 85% to a stable 98%. The FRACAS process provided a data-driven framework to find and eliminate systemic issues, ensuring quality at scale.

Successfully scaling an SoC-based product requires appreciating the immense complexity of the manufacturing environment. Details like gas analysis in semiconductor manufacturing are critical for chip quality, and that same level of rigor is required on the assembly line to build a reliable end product.

SoCs in the Real World: High-Stakes Applications

The true test of a System on Chip is its performance in environments where failure is not an option. Examining how SoCs are deployed in demanding, high-stakes industries makes the technical trade-offs we've discussed more tangible, connecting architectural choices directly to mission-critical outcomes.

While consumer electronics like smartphones currently dominate the SoC market—projected at 42.28% in 2025—the principles of high integration and power efficiency are just as vital in regulated industries. The global SoC market is forecast to reach USD 206.26 billion in 2025, with significant growth coming from sectors where reliability is paramount. You can explore the SoC market landscape on Coherent Market Insights for more detail.

Medical Devices: The Wearable Glucose Monitor

Consider an SoC at the core of a wearable continuous glucose monitor. Here, patient safety is the primary stake, and the technical constraints are extreme.

• The Core Challenge: The device must operate on ultra-low power to maximize battery life, often for weeks. It needs to perform sensitive analog signal processing, run complex algorithms, and maintain a BLE connection, all while consuming mere microamps in its idle state.
• The SoC Solution: An SoC that integrates a low-power MCU, a high-precision analog-to-digital converter (ADC), and an efficient BLE radio on a single die is the ideal choice. This integration eliminates the power-hungry communication that would occur between discrete components.
• The Business Impact: Firmware for this device must be developed under the strict regulations of IEC 62304, where software reliability is directly tied to patient safety. A well-chosen SoC simplifies hardware validation, allowing the engineering team to focus on building robust, compliant firmware, which ultimately creates a faster, safer path to regulatory approval and market entry.

Aerospace and Defense: The UAV Flight Control Computer

Now, consider a flight control computer for an unmanned aerial vehicle (UAV). Mission success depends entirely on the system's ability to process a massive stream of sensor data and react with deterministic, real-time performance.

• The Core Challenge: The system must fuse data from an IMU, GPS, and lidar, executing control loop algorithms with hard real-time guarantees. A single missed deadline is not a minor glitch; it is a potential catastrophic failure.
• The SoC Solution: A heterogeneous SoC, which combines multiple CPU cores with an FPGA fabric, is a powerful choice. The CPUs handle high-level mission logic, while the FPGA provides unparalleled performance for parallel sensor data processing and implementing custom, low-latency control interfaces.
• The Business Impact: The verification and validation (V&V) effort for such a system is immense, often governed by stringent standards like DO-178C for software. The choice of an SoC directly impacts the complexity of the V&V process. A single-chip solution simplifies thermal management and dramatically reduces the number of potential hardware failure points compared to a multi-chip design, creating a foundation for a more robust and certifiable system.

In high-reliability applications, SoC selection is about more than performance-per-watt. It’s about architecting a verifiable system with fewer failure modes. Integrating critical functions onto a single die reduces interconnects, simplifies the supply chain, and shrinks the attack surface for security vulnerabilities.

Industrial Robotics: The Autonomous Warehouse Robot

Finally, consider an autonomous warehouse robot, a prime example of how SoCs are enabling powerful edge computing to drive operational efficiency.

• The Core Challenge: The robot must navigate a dynamic environment, identifying obstacles and optimizing its path in real-time. Sending sensor data to the cloud for processing is not feasible due to latency; decisions must be made instantly, at the edge.
• The SoC Solution: An SoC with integrated AI/ML acceleration cores is ideal for this task. These specialized cores can run complex neural networks for object detection and navigation directly on the device, providing the near-instantaneous response required for safe and effective operation.
• The Business Impact: On-device processing reduces reliance on network connectivity and eliminates ongoing cloud computing costs. This creates a more responsive, reliable, and scalable robotic fleet that directly increases warehouse throughput and operational efficiency.

A Few Hard Questions About System on Chip Strategy

Let’s get practical. Engineering leaders and program managers always run into the same tough questions when an SoC design is on the table. Here are some straight answers based on our experience, focused on tradeoffs, risk, and getting it right the first time.

How Early Do We Really Need to Decide Between a Custom SoC and a SoM?

This isn't a decision you can kick down the road. The choice between a custom SoC and a System on Module (SoM) has to be made right at the beginning, during the initial architecture phase, long before anyone starts laying out a board. Why? Because this single choice dictates your project's cost, timeline, and the very structure of your team.

We've seen this go wrong too many times. A team prototypes with a SoM, telling themselves they'll "switch to a custom chip later" to save on costs. They almost always underestimate the monumental effort of a full custom layout, and it leads to massive, painful schedule resets down the line.

Here’s a clear rule of thumb: take a hard look at your projected production volume. If you're looking at less than 10,000 units a year, the staggering NRE cost of a custom SoC is almost impossible to justify.

What's the Biggest Hidden Risk in SoC Projects?

It's almost always the integration of firmware and hardware. On paper, teams schedule PCB layout and software development as two parallel, separate tasks. The real chaos begins where those two streams meet.

Simple-sounding issues like incorrect memory timing, misconfigured pinmux settings, or flawed power sequencing can bring a board bring-up to a dead stop. These problems are a nightmare to debug because they aren't just a hardware bug or a software bug—they're a system-level failure.

The only effective way to kill this risk is to have a single technical owner who is responsible for both hardware validation and firmware bring-up. This structure prevents the finger-pointing that paralyzes siloed teams when they're staring at a "dead" board.

Can We Just Fix DFM or DFT Issues After the First Prototype?

Trying to fix fundamental Design for Manufacturing (DFM) or Design for Testability (DFT) problems after you have your first EVT (Engineering Validation Test) prototype in hand is brutally expensive and slow. Things like realizing you don't have adequate test point access or discovering a flawed BGA escape routing strategy often mean one thing: a full board re-layout.

This mistake triggers a cascade of delays. You're not just looking at new fab and assembly cycles; you're looking at a complete re-validation of the new hardware from scratch. DFT and DFM have to be treated as primary design requirements from day one, not as clean-up items for later.

Navigating the complexities of SoC design requires integrated expertise across hardware, firmware, and manufacturing. If your team is grappling with architectural trade-offs or facing a complex board bring-up, Sheridan Technologies provides the unified engineering support to de-risk your program and accelerate your path to production.

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