PCB design is one of the most critical stages of electronic product development. A small mistake can lead to major costs and lost time in production. Here are the most common mistakes and their solutions:

1. Insufficient Copper Clearance

If the distance between traces falls below the manufacturing capability, the risk of a short circuit increases.

Solution: Enter your manufacturer’s minimum clearance values (usually 0.15mm+) as a design rule. For high-voltage traces, refer to the IPC-2221 standards.

2. Lack of Thermal Relief

Pads connected to large copper pour areas dissipate heat during soldering and create cold joints.

Solution: Use thermal relief on ground plane connections. This is especially critical on boards that will be hand-soldered.

3. Via-in-Pad Problems

Vias placed on top of an SMD pad cause solder to flow down through the via during reflow.

Solution: If you must use via-in-pad, specify the vias as plugged/filled. If possible, move the via off the pad.

4. Decoupling Capacitor Placement

Bypass capacitors placed far from the ICs lose their effectiveness.

Solution: Connect 100nF decoupling capacitors as close as possible to the IC’s power pins, tying them directly to the ground plane with a via.

5. Incorrect Footprint

The wrong pad size or pin pitch leads to disaster during assembly.

Solution: Always compare every new footprint against the datasheet. Use the IPC-7351 standard as a reference. Check with 3D visualization before the first production run.

6. Neglecting Signal Integrity

On high-speed signals (USB, Ethernet, SPI >10MHz), impedance mismatch causes data errors.

Solution: Route differential pairs at equal lengths. Perform a stack-up calculation for impedance-controlled design.

7. Power Plane Splits

Unnecessary breaks in the power and ground planes cause return path problems.

Solution: Keep the ground plane as uninterrupted as possible. Do not route signal traces over plane splits.

8. Mechanical Mismatch

The PCB dimensions, mounting holes or connector positions do not match the mechanical design.

Solution: Import the mechanical design into your PCB tools as a STEP file. Make active use of 3D visualization.

9. Silkscreen Errors

Unreadable silkscreen, or silkscreen printed over pads, makes assembly difficult.

Solution: Use a minimum font height of 0.8mm and a line width of 0.15mm. Check for pad-silkscreen overlap with DRC.

10. Missing Production Files

A missing gerber layer, drill file, or a pick-and-place error will halt production.

Solution: Create a production output checklist: Gerber (all layers), drill (PTH + NPTH), BOM, pick-and-place (centroid), stack-up information.

Conclusion

Most of these mistakes can be prevented with a systematic design review process. At MARG Engineering, we perform DFM analysis on every project and provide comprehensive pre-production checks.

If you need PCB design support, get in touch with us.

Related Content