10 PCB Design Mistakes That Damage Product Reliability
Your PCB design can look flawless in CAD.
But if it can’t survive once customers start using it, then you don’t have a product, you have a prototype.
And a prototype that fails after shipping isn’t just annoying.
It’s expensive. It’s embarrassing. And it makes your company or product look bad.
Reliability is what makes or breaks a product once it ships to your customer.
And unfortunately, it’s also one of the most commonly overlooked aspects during design.
These are 10 of the most common PCB design mistakes that quietly destroy reliability, and how to avoid every one of them.
Mistake 1: Thermal Mismanagement
Heat is one of the biggest long-term killers in electronics.
Just a 20°C increase in temperature can cut a component’s lifetime in half.
The problem is, thermal issues rarely show up during short prototype tests.
They show up after hours of use. Or after months in a sealed enclosure.
Power devices that feel warm on the bench can hit failure thresholds in production, especially if there’s no airflow or internal spacing.
Even something as simple as a darker-colored plastic enclosure can cause higher internal temps.
Too much heat over time causes capacitors to dry out, solder joints to fatigue, and chips to degrade.
And once it starts, the failure spreads fast.
To avoid this, spread out hot components, use wide copper pours and thermal vias under heat-generating parts, and don’t place hot parts in corners or tight spots where heat can’t escape.
And verify everything with a thermal camera, not just your fingers.
Test the full system at full load over extended periods of time.
Mistake 2: Inadequate Power Supply Design
The power supply isn’t just another circuit block, it’s the root of your board’s reliability.
If it’s not solid, every other section becomes unreliable.
Designers often pick regulators based on current rating alone, ignoring thermal performance, startup behavior, and transient response.
One classic trap is not accounting for peak current when everything powers up at once.
You might be okay during idle, but when Wi-Fi transmits, or a screen lights up, things brown out.
The symptoms aren’t always obvious.
You might get weird resets, inconsistent behavior, or sensors randomly dropping off the bus.
All of that can come down to inadequate power design.
Always build in thermal and current headroom, choose regulators based on worst-case load and ambient temperatures.
Use a mix of low and high-value capacitors near all active ICs, and validate under fast load changes, startup conditions, and low battery voltage.
Mistake 3: Poor Component Derating
Datasheets give you maximum ratings, not always the safe operating points.
If you treat those numbers like targets, you’re asking for trouble.
Take electrolytic capacitors. A 25V cap on a 24V rail might survive in the lab.
But in the field, that same cap may dry out in less than a year.
Resistors are another one. Run them too hot, and their value drifts until your circuit stops working right.
To avoid this, use solid derating practices. Capacitors should be rated for at least 2x their applied voltage.
Resistors should be derated to 50% of their rated power or less.
And switching devices should be tested under real-world waveforms and loads, not just DC.
Proper derating is one of the easiest ways to make a product last for years instead of months.
Mistake 4: Weak Solder Joint Reliability
Solder joints aren’t just electrical connections, they’re structural.
They’re one of the most failure-prone elements of any product, especially in handheld or mobile devices.
Cold joints, cracked joints, and stressed pads are incredibly common, especially during long-term vibration or thermal cycling.
One frequent mistake is skipping thermal reliefs on power or ground planes.
That leads to joints that don’t heat evenly during reflow, creating voids or weak connections.
Another is using via-in-pad without proper filling, which causes solder wicking and starves the joint.
You can’t afford to overlook these in a real product.
Use thermal reliefs to allow balanced solder flow, avoid via-in-pad unless the via is filled, capped, and plated.
Reinforce connectors and heavy components with mechanical brackets if the product faces shock or vibration.
And always inspect solder quality during early production.
Mistake 5: Ignoring Environmental Protection
PCBs aren’t living in clean, dry labs.
They’re getting used outside, and in homes, factories, vehicles, and warehouses.
And that means they face moisture, dust, condensation, ESD, and sometimes some bugs (the crawling type – not the software type)
If you don’t protect your PCB from these things, even a great design will eventually fail.
Condensation alone can corrode traces in just a few months.
Dust buildup across high-voltage nets creates arcing or leakage paths.
Static shocks at a USB port may not cause immediate damage, but they degrade sensitive silicon over time.
Use conformal coating if your product will see any kind of moisture or humidity.
Respect creepage and clearance standards, especially on AC mains or high-voltage switching.
And always protect external interfaces with ESD protection.
Mistake 6: Poor Connector and Mechanical Design
You can have a perfect circuit and still fail because of a single weak connector.
Edge-mounted connectors with no support flex over time, cracking solder joints.
And placing connectors far from mounting holes means any tug or twist puts stress directly on the PCB.
We went through multiple Amazon Fire tablets in our house, and every single one failed the same way.
The USB port wore out from repeated plugging and unplugging.
That kind of failure frustrates users and kills brand trust.
In this case, thankfully newer USB-C connectors are so much more robust.
Always reinforce connectors with mechanical mounting points, especially those that will see repeated plugging and unplugging.
And give every cable strain relief, even if it feels like overkill.
Mistake 7: Choosing a Battery Without Proper Protection
Batteries are one of the most dangerous components in your product.
Designs that skip proper battery protection quickly run into swelling, fires, short circuits, or outright shutdowns in the field.
Even when using reputable lithium cells, protection is essential.
That includes protection against overcharging, deep discharge, over-current, and thermal runaway.
A good battery pack includes this circuitry built-in, which is always my preference.
If you’re integrating raw cells yourself, you need to add your own protection circuitry, which adds considerable complexity and liability.
Any custom designed protection circuitry must be thoroughly tested under all worst-case conditions.
Reliability here isn’t just about avoiding warranty claims and unhappy customers.
It’s about safety and liability.
Mistake 8: Ignoring Vibration and Mechanical Stress
Electronics don’t just sit on a desk. They get dropped, tossed, shaken, and packed into tight housings with little support.
Even gentle vibration over time causes solder joints to crack, pads to lift, and components to fail.
Tall components like relays or transformers act like levers, rocking back and forth until they tear themselves off the board.
Boards flex during assembly or installation, and that flex can fracture BGA joints or weaken traces.
Designers often don’t think about these forces until it’s too late.
Use standoffs and mounting holes to keep the board fixed in place. Add adhesive or mechanical supports under tall components.
For long or narrow PCBs, increase board thickness or add stiffeners.
And test with drop, vibration, and even twist scenarios.
Mistake 9: Using the Wrong Capacitor Types
Capacitors are everywhere in a design, but they’re not all the same.
If you treat all caps interchangeable, your product won’t last.
Electrolytics are great for bulk energy storage, but terrible for high-frequency decoupling.
Ceramics are good for high-speed transients, but their effective capacitance drops significantly under voltage, especially Class II types like X7R.
And small ceramics simply don’t have enough energy storage on their own.
That means you might get a power rail that looks fine during development but becomes noisy, unstable, or sagging in production.
It’s usually best to use a mix of capacitor types.
Use ceramics for high-frequency filtering near IC pins.
Use electrolytics or tantalums for bulk storage near power entry points or regulators.
And always check derated capacitance under voltage, not just the value printed on the part.
Mistake 10: Using Marginal PCB Materials
Not all FR-4 is created equal.
Cheap board material might pass your prototype build, but it’s often the root cause of long-term failures.
Low-grade laminates absorb moisture, which leads to leakage paths between nets.
Under heat, they warp or delaminate, especially near hot power devices.
And at higher frequencies, poor materials cause impedance variation, signal degradation, or even dielectric breakdown.
If you’re designing a product that needs to last, use higher-Tg laminates.
Ask your manufacturer what specific material they’re using, and don’t just accept “FR-4” as an answer.
For RF, high-voltage, or high-temperature designs, consider specialty materials.
And make sure production runs don’t substitute cheaper materials without notice.
Your board is only as reliable as the stuff it’s made from.
If you’d like help avoiding these types of mistakes on your designs check out the Hardware Academy.
And if you found this video helpful then you’ll probably like these other videos in this same series aimed at helping you avoid costly mistakes.
