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  1. #1
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    Good PCB Layout Designers

    One could spend hours trying to make the board look pretty, doing the correct routing, grounding, decoupling. In the end the only thing that matters is that it passes EMC testing.

    Can one ever be considered good at PCB layout until they have at least a couple of designs under their belt which have passed EMC testing?

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    Re: Good PCB Layout Designers

    Quote Originally Posted by coates View Post
    One could spend hours trying to make the board look pretty, doing the correct routing, grounding, decoupling. In the end the only thing that matters is that it passes EMC testing.

    Can one ever be considered good at PCB layout until they have at least a couple of designs under their belt which have passed EMC testing?
    Wrong, wrong, wrong. EMC testing is hardly “the only thing that matters”. What about trace impedance? What about timing constraints? What about testing? What about manufacturability? What about thermal considerations? What about trace current capacity?

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    Re: Good PCB Layout Designers

    spend hours trying to make the board look pretty, doing the correct routing, grounding, decoupling...
    The thing has a beauty of its own. If you do proper routing, grounding and decoupling, the board is already looking quite pretty.

    Once the basics are taken care of, most things (mostly) fall automagically into their proper place. Why it will fail the test?

    A well designed board is a thing of beauty!

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    Re: Good PCB Layout Designers

    Quote Originally Posted by barry View Post
    Wrong, wrong, wrong. EMC testing is hardly “the only thing that matters”. What about trace impedance? What about timing constraints? What about testing? What about manufacturability? What about thermal considerations? What about trace current capacity?
    Assuming a board "works" then all of these things would be satisfied. They can be tested and verified at home.

    The thing that I don't like is that it's misleading for hobbyists in electronics that have come from Adafruit, Arduino, etc. and want make the leap from "working" electronics to saleable electronics.

    They should be made aware from the get-go they will need A LOT of money and access to a testing lab before they can really pursue a career in electronics design. Particularly if you're starting your own business and don't have the purchasing power of a big company financing your mistakes.

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    Re: Good PCB Layout Designers

    the get-go they will need A LOT of money and access to a testing lab before they can really pursue a career in electronics design...
    Perhaps only partially true; once you get a theoretical understanding, you can perhaps guess weak points in the design. Access to testing labs can also be critical and professional testing labs give you results like "pass" or "failed" which is just not enough for debugging a complex circuit.

    Perhaps you will agree that component prices are low (and getting lower) and designs are getting more modular (that helps debugging less than a nightmare) and overall circuits are getting more complex.

    I personally think that "working electronics" to "saleable electronics" is not a single jump but a series of small steps. It is not a direct transformation of design from hobby to commerce!

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    Re: Good PCB Layout Designers

    I would say just do a PCB with all the positive and negative side effects. Usually the first PCBs are based on a reference design anyway there's little someone can do wrong.

    Learning by failing. I just did an FPGA project and failed like 2 weeks with it until the failing paths were sorted out.

    But interestingly I also got the information there are many more skills required for what I want to do.

    When doing my first PCB I jumped into the cold water (without any knowledge, since I'm a software guy) and it surprisingly worked.
    A company has quoted me 25.000 USD for designing it, I decided to buy a good EDA software and electronic equipment instead to do it myself. I have sourced which equipment I need in the internet (the only bad part was a tektronix oscilloscope with too less memory). That was like 5 years ago and I turned it into a business.

    My motivation: I once worked for a small IC design house, their hardware engineers were so bad (design and layout) so I thought I can be that terrible too at least.

    However all that is very time consuming, I did not take it easy going since I wanted to fund my life out of this, additionally I did that in [swearing] [a crappy country with no future for me in central europe], nowadays I have left the country because the taxes are unreasonable high (and they really put all the risk on the small business' [after taxes], also they won't help at all and kick you into your butt if you're lying on the ground already.. ).

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    Re: Good PCB Layout Designers

    Quote Originally Posted by player80 View Post
    I would say just do a PCB with all the positive and negative side effects. Usually the first PCBs are based on a reference design anyway there's little someone can do wrong.

    Learning by failing. I just did an FPGA project and failed like 2 weeks with it until the failing paths were sorted out.

    But interestingly I also got the information there are many more skills required for what I want to do.

    When doing my first PCB I jumped into the cold water (without any knowledge, since I'm a software guy) and it surprisingly worked.
    A company has quoted me 25.000 USD for designing it, I decided to buy a good EDA software and electronic equipment instead to do it myself. I have sourced which equipment I need in the internet (the only bad part was a tektronix oscilloscope with too less memory). That was like 5 years ago and I turned it into a business.

    My motivation: I once worked for a small IC design house, their hardware engineers were so bad (design and layout) so I thought I can be that terrible too at least.

    However all that is very time consuming, I did not take it easy going since I wanted to fund my life out of this, additionally I did that in [swearing] [a crappy country with no future for me in central europe], nowadays I have left the country because the taxes are unreasonable high (and they really put all the risk on the small business' [after taxes], also they won't help at all and kick you into your butt if you're lying on the ground already.. ).
    Thanks for your story, player80. You didn't mention anything about EMC testing. Have you had any experience?

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    Re: Good PCB Layout Designers

    Quote Originally Posted by coates View Post
    Thanks for your story, player80. You didn't mention anything about EMC testing. Have you had any experience?
    I'm in Taiwan nowadays, I never had any issue with EMC (maybe luck, or I have just studied too many competitive products well enough before I did my pcbs)?
    Although I went to a lab several times (due to several products) before pushing out my products. Just go to a lab nearby and ask if they can help or advice some help.

    Different products will have different requirements!

    Especially the smaller labs which I have visited looked like they're able to help.

    You would have to disclose your product if you want to get help in that direction, either in real life or in this forum.
    For diving a bit into EMV you can check some youtube videos (which you might have seen already), but as mentioned if you ask for help people for sure need to know your product.

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  9. #9
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    Re: Good PCB Layout Designers

    Quote Originally Posted by player80 View Post
    I'm in Taiwan nowadays, I never had any issue with EMC (maybe luck, or I have just studied too many competitive products well enough before I did my pcbs)?
    Although I went to a lab several times (due to several products) before pushing out my products. Just go to a lab nearby and ask if they can help or advice some help.

    Different products will have different requirements!

    Especially the smaller labs which I have visited looked like they're able to help.

    You would have to disclose your product if you want to get help in that direction, either in real life or in this forum.
    For diving a bit into EMV you can check some youtube videos (which you might have seen already), but as mentioned if you ask for help people for sure need to know your product.
    Do you mainly use 2 layer or 4+ layer PCBs for your products? Getting mixed advice from the internet about whether it's possible to pass EMC with 2-layer PCBs sometimes. On the other hand, have only ever seen 2-layer PCBs in tear-downs.

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    Re: Good PCB Layout Designers

    Hi,

    For sure it's possible to pass EMC test with 2 layers.
    I've done it many times. But it needs to know about the crutical current loops, enclosed area of the loop, frequencies.
    Proper placement is one key to good success.

    Klaus
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  11. #11
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    Re: Good PCB Layout Designers

    Quote Originally Posted by coates View Post
    Do you mainly use 2 layer or 4+ layer PCBs for your products? Getting mixed advice from the internet about whether it's possible to pass EMC with 2-layer PCBs sometimes. On the other hand, have only ever seen 2-layer PCBs in tear-downs.
    it really depends on a few items, what are you trying to do?
    It depends on the chipsets, frequency (not particular on the frequency itself but also on the rise time). An edgy looking signal has a high frequency content (as seen in the frequency domain, and that might be a cause for EMV problems).

    You cannot give a generic statement about if a 2 layer board vs 4 layerboard can be used for a project. You didn't even write which components you are using.
    You better roughly describe what you want to do and/or which components you plan to use.

    My 4 layer board should have been done as a 6 layer board back then though it has passed the EMV test with 4 layers. I was using DQFNs (a nightmare to start with as beginner, especially the soldering part since you cannot look below the chipset and even professional assembly houses shorted them for me, an experienced assembly house in Taiwan was able to solder it with a good yield back then.. that's also why I moved there finally .. much less pain) and a few QFNs.

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