Common PCB Design Mistakes and How to Avoid Them

Printed Circuit Board (PCB) design is a crucial aspect of electronics development, impacting performance, reliability, and manufacturability. Engineers, product developers, and businesses must be aware of common pitfalls to ensure their designs meet industry standards.

In this blog, we will explore the most common PCB design mistakes and provide strategies to mitigate them.

What is PCB Design?

PCB design is the process of creating the layout for a printed circuit board, which serves as the foundation for electronic components to interconnect and function correctly. It involves schematic design, component placement, routing, and final production considerations.

Optimising PCB layout is essential for performance and manufacturability. Learn more about Hetech’s PCB design solutions.

Why is it Important?

A well-designed PCB is the backbone of any reliable electronic device. It ensures:

• Superior electrical performance, reducing signal loss and enhancing efficiency.
• Minimised risk of failures and defects, preventing costly rework and product recalls.
• Streamlined manufacturing processes, making production faster and more cost-effective.
• Scalability for future growth, allowing for easy modifications and upgrades as technology advances.

Most Common PCB Design Mistakes

Poor Component Placement

Incorrect component placement can lead to signal integrity issues, increased EMI (Electromagnetic Interference), and difficulty in manufacturing. To avoid this:

• Follow a logical component grouping based on function – For example, placing decoupling capacitors close to power pins reduces noise and improves stability.
• Maintain proper spacing for heat dissipation – High-power components like voltage regulators should have enough space for airflow to prevent overheating.
• Consider accessibility for testing and troubleshooting – Placing test points on critical signals makes debugging easier during development and production.

Inadequate Trace Width & Spacing

Improper trace width and spacing can cause overheating, short circuits, and signal integrity issues. To prevent these problems:

• Follow IPC-2221 guidelines for minimum trace width and spacing to ensure electrical reliability. For example, high-voltage PCBs require larger spacing to prevent arcing.
• Match trace width to current requirements—narrow traces can overheat and fail under high loads. For instance, a power trace carrying 3A should be wider than a signal trace.
• Maintain adequate clearance to prevent unintended shorts and electrical arcing. A common mistake is placing high-voltage traces too close together, increasing the risk of breakdown.
• Use ground planes and proper routing to reduce electromagnetic interference (EMI) and improve heat dissipation. For example, a continuous ground plane under high-speed traces minimises noise and signal distortion.

Lack of Design for Manufacturability (DFM) Considerations

Ignoring DFM principles can lead to increased production costs, manufacturing defects, and delays. To prevent this:

• Adhere to manufacturer’s design constraints – For example, ensuring minimum trace width and spacing requirements match fabrication capabilities prevents production issues.
• Minimise the number of vias and complex routing – Excessive vias increase manufacturing complexity and cost; instead, optimise routing for efficiency.
• Ensure proper solder mask clearances and pad sizes – Incorrect clearances can cause solder bridging or poor connections, leading to reliability issues.

Ignoring Thermal Management

Poor thermal management can lead to component failure and reduced lifespan. Mitigation strategies include:

• Using thermal vias to dissipate heat – For example, placing multiple vias under a heat-generating component can help transfer heat to other PCB layers efficiently.
• Placing high-power components strategically – Keeping power-hungry components away from heat-sensitive parts, like microcontrollers, prevents thermal interference.
• Implementing heat sinks and copper pours – Large copper areas or attached heat sinks can effectively dissipate excess heat, ensuring stable operation.

Not Accounting for Signal Integrity & EMI

Failure to manage signal integrity and EMI can cause interference, leading to malfunctioning devices. To address this:

• Use ground planes to reduce noise – A continuous ground plane beneath signal traces helps minimise electromagnetic interference.
• Maintain controlled impedance for high-speed signals – Matching trace impedance with connected components prevents signal loss and distortion, crucial for RF circuits.
• Avoid right-angle traces to prevent signal reflection – Sharp turns in high-frequency traces can cause signal degradation; instead, use 45-degree angles or curved traces.

Skipping Proper Prototyping & Testing

Overlooking thorough prototyping and testing can result in costly redesigns and product failures. Best practices include:

• Conducting Design Rule Checks (DRC) before production – Automated DRC tools help catch layout errors early, such as incorrect trace widths or spacing violations.
• Performing signal integrity simulations – Simulating high-speed signals can identify potential interference issues before manufacturing.
• Testing prototypes under real-world conditions – For example, exposing the PCB to extreme temperatures and humidity ensures it performs reliably in its intended environment.

Best Practices to Avoid PCB Design Mistakes

To ensure a high-quality, reliable PCB design, it’s essential to follow best practices that enhance performance and manufacturability. Here are some key strategies:

• Develop a clear design strategy early on to avoid costly revisions and delays.
• Utilise industry-leading PCB design software to optimise layout, routing, and component placement.
• Work closely with experienced manufacturers like Hetech to ensure design-for-manufacturability (DFM) considerations are met.
• Perform rigorous testing and prototyping to validate your design before mass production.

At Hetech, we specialise in high-quality PCB design and manufacturing, ensuring our clients receive reliable and efficient electronic solutions. Contact us today to bring your PCB projects to life!