Think when designing a PCB
April 07, 2017
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To many people designing a printed circuit board (PCB) is more or less an (annoying) detail or a mere afterthought. The circuit has been tested thoroughly, and then, without thinking about it too much, they plunk it on a circuit board to make it easier to move around, hopefully without any wires coming loose or components dropping off.
Even if such a naive approach may work for simple, low-power, and low-frequency circuits, it is wrong. Simple circuits need good PCBs too. Good PCBs not only make a circuit work reliably and as intended, they also limit radiated noise as much as possible, they provide test points for system assembly and repair, and they are easy to fit in the final application.
Because that is what a circuit board really is, a component within a larger system, and as such it has to be as good as any other component used in that system. A PCB design isn’t intended to please the designer, it should please the end user, whoever that may be.
So, the next time you design a PCB, please think it through a bit further. It doesn’t have to be as small as possible; you are allowed to use text objects, and please, please, don’t forget the mounting holes.
Here's one more afterthought: what about the board’s power supply? Did you think about that?
Even if such a naive approach may work for simple, low-power, and low-frequency circuits, it is wrong. Simple circuits need good PCBs too. Good PCBs not only make a circuit work reliably and as intended, they also limit radiated noise as much as possible, they provide test points for system assembly and repair, and they are easy to fit in the final application.
Because that is what a circuit board really is, a component within a larger system, and as such it has to be as good as any other component used in that system. A PCB design isn’t intended to please the designer, it should please the end user, whoever that may be.
So, the next time you design a PCB, please think it through a bit further. It doesn’t have to be as small as possible; you are allowed to use text objects, and please, please, don’t forget the mounting holes.
Here's one more afterthought: what about the board’s power supply? Did you think about that?
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About Clemens Valens
Started working for Elektor in 2008 as editor in chief of Elektor France; was involved for a while with the Elektor websites and has since been active as technical manager of the lab. Is also editor for Elektor UK/US and Elektor Online.
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Discussion (6 comments)
James Smith 7 years ago
Dego 7 years ago
Both a good schematic and a good layout are thus as essential for an well working design!
C:
Dave Whitaker 7 years ago
Not only the power supply- I find that heat dessipation needs to be seriously considered before you lay out the PCB. Overheating is probably the hardest thing to rectify once the board is made. See my blog "Power Dissipation: My Arch-Nemesis"
ShanevanJ 7 years ago
Andrew Rukangu 7 years ago
magicChristian 7 years ago
A layout for hobby purpose will be sufficient if not perfect, if used within a commercial produced product the layout as well as th schematic should be as perfect as possible. This includes outline position and orientation of connectors, placement of components, mounting holes and number of vias. A simulation may help to have useful boards with the first lot.
Another very important issue is high frequency and electromagnetic radiation. Digital signals with fast edges and long wires will result in EM Noise. Modern µC often allow to choose between fast and moderate edges on output pins.
For really fast signals much care is necessary also for signal delay on PC traces which needs the layout to be done by specialist.