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Avoid the Common PCB Circuit Design Mistakes

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Published by Pinsheng Electronics Co., Ltd July 13,2019

 

PCB Circuit Design Mistakes Waste Your Time and Money


You know PCB circuit design cost your much time and energy, and if some design mistakes flow to the PCB manufacturing stage (I know you will never go wrong, but maybe you were just too tired at that time and no coffee...), they will cause difficulties to the manufacturing, lead to an unexpected delay even waste double or triple your cost.

We have seen too many failures caused by little PCB circuit design mistakes and listed out the common 12 errors for your reference to avoid.


The 12 Common PCB Circuit Design Mistakes

1. Pads Overlap

  • Causes holes overlapping, which will lead to drilling failure and hole damage,
  • In the multi-layer PCB, that one pad possesses multiple properties may cause connection errors.

2. Uncanonical Copper Layers

  • Unreasonable design, such as putting components in the Bottom layer, or setting TOP layer as the soldering surface,
  • There is a lot of design garbage on each layer, such as unconnected lines, useless borders, labels, etc.

3. Unreasonable Overlays

  • The characters cover the SMD pads, this will brings inconvenience to the PCB circuit testing and component soldering,
  • Too small characters will make printing difficult, too large ones will cause overlapping, difficult to recognize. The size should be generally > 40mil.

silk covers the SMD pad

4. Set Apertures for Single-sided Pads

  • The single-sided pad generally doesn't require drilling, and its aperture should be designed to be zero. Otherwise, when the drilling data get generated, unnecessary coordinate will get produced at this position. But if indeed require drilling, note in the file,
  • If a single-sided pad requires drilling, but the aperture is not designed, the software will treat the pad as an SMT pad.

5. Draw Pads with Padding

  • Although this can get through DRC, the soldermask data cannot be directly generated during processing, and the pad will be covered by the solder resist.

6. The GND layer is designed with both heat sink and signal lines, and the positive patterns get mixed with the negative,  which occurs error.

7. Grid Spacing is too Small

  • Grid line-spacing <0.3mm, the traces may get cut off in the development of PCB manufacturing processing, which raises processing difficulty.

8. The Traces Are too Close to The Outer Frame

  • At least 0.2mm or more (For V-cut, 0.35mm or more) should be ensured, otherwise, the copper foil may get warped and the soldermask may fall off, which will affect the appearance quality.

9. The Design of The Outline is Not Clear

  • Many layers are designed with the outlines which do not overlap, it makes it difficult for PCB manufacturers to judge which one is to be formed. The standard outline should be put in the mechanical layer or board layer, and the slotting parts should be clear.

PCB outlines

10. Uneven Pattern Design

  • In the pattern electroplating, the current distribution will be uneven, which affects the uniformity of the copper layer and even causes warpage.

11. Short Irregular Holes

  • The length/width of the irregular holes should be >2:1, and the width should be >1.0mm, otherwise, the CNC machines cannot make them.

12. Not Design Aligned Holes

  • If possible, add at least 2 aligned holes with a diameter of >1.5mm on the PCB.

PS Electronics understands the pains caused by these mistakes, so we provide free technical support to remove them from your PCBs before manufacturing. 

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