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Keepout Vary and Via Stitching and Via Shielding

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  • Keepout Vary and Via Stitching and Via Shielding

    Hello Everyone,

    I would like to ask two questions about PCB as usual.

    Firstly, What is the difference between keepout layer, keepout fill, and keepout region? Are there any advantages or disadvantages to those types? How can I decide best to select for those types?

    Last of all, Similar to the previous question What is the difference between Via Stitching and Via Shielding? And Where I must use these VIA types. How can I decide best to select for those types?
    I think those are important in PCB design but I am a freshman and I want to learn PCB design because this is my enthusiasm and my life. One by one, step by step. And Sure this forum is a big treasure for me and all beginner.

    Thank you for your Feedbacks in advance.


  • #2
    Hi Furkan,

    Via stitching is used to tie together larger copper areas on different layers, creating a low impedance and short return loops.

    Eg: 1) Stitching ground pour between layers using vias.

    2) To carry excessive currents, multiple copper area/polygon can be overlapped on different layers and tied together with via stitching.

    Constrains and via parameters can be defined before stitching nets together.

    Via shielding on the other hand is mostly related to RF designs. Track carrying RF signals can transmit EMI and is mitigated by isolating it with ground vias along the track. This might help:

    Keepout layer is just a layer where you can define areas/regions using 'fill keep out' and the software won't let you route signals or place vias/ parts in that specified area. This void/barrier will be common to all the other signals and plane layers.
    Fill Keepout can be used to define a void or a barrier region. It could also be placed on any signal/plane region to take effect only on that specific layer.

    I suggest you work on a dummy board and start experimenting with different tools, good luck.



    • #3
      Excellent answer grrmachine

      I would like to just add about keepouts ... there is nothing really special about them - these are just areas where you do not want to have specific objects ... and I do not really use them much. When you try to draw them you will see the differences ... e.g. fill is just a rectangle, region is like a polygon etc.


      • #4
        I have used the keep out area on high speed traces because those are usually very short.. and setting up rules for everything takes time.. sometime it's easier to create the clearance from polygons like that also when placing a keep out area you can do it on a specific area.