5 Replies Latest reply on Jan 8, 2013 9:54 AM by tipo1000

    Question about thermal relief (spoke) widths

    tipo1000

      I noticed that thermal relief (spoke) widths are same for 0805 and 0603, about 20 mils.

      For SOD-323 they are about 11 mils.

      The width of GND polygon where they connect is 10 mils.

       

      Is that how it is supposed to be? How Eagle decides that?

       

      Thanks.

        • Re: Question about thermal relief (spoke) widths
          000Plasma000

          I'm not too sure about this, but I think you can change these in the DRC window. Does it really matter for your application though? For things like 0603 resistors and caps, it doesn't make much of a difference, but with DC power jacks, I've noticed that the default width generated is too thick, and I have trouble soldering the ground pins on.

            • Re: Question about thermal relief (spoke) widths

              On 1/7/2013 4:40 AM, Rahul Swaminathan wrote:

              I'm not too sure about this, but I think you can change these in the DRC window. Does it really matter for your application though? For things like 0603 resistors and caps, it doesn't make much of a difference, but with DC power jacks, I've noticed that the default width generated is too thick, and I have trouble soldering the ground pins on.

               

               

              Hi Guys,

               

              The thickness of the thermal relief spokes is determined by the width of

              the polygon. So if your polygon width is set to 10 mils your spoke

              traces will have a width of 10 mils.

               

              hth,

              Jorge Garcia

              Cadsoft Computer

               

              • Re: Question about thermal relief (spoke) w idths
                tipo1000

                Yes, that makes sense.

                 

                Thanks!

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              • Re: Question about thermal relief (spoke) widths

                Mark Perry wrote:

                I noticed that thermal relief (spoke) widths are same for 0805 and

                0603, about 20 mils. For SOD-323 they are about 11 mils.

                The width of GND polygon where they connect is 10 mils.

                 

                Is that how it is supposed to be? How Eagle decides that?

                 

                Thanks.

                 

                Search for "Thermals" in the manual.

                 

                In essence the spoke width is 25% of the drill diameter of the pad. but

                between 1 and 2 wire widths of the polygon.

                For a SMD I believe I read somewhere that it is based on the smallest side

                of the SMD.

                 

                Warren

                 

                 

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                  • Re: Question about thermal relief (spoke) widths

                    Warren Brayshaw wrote:

                    Mark Perry wrote:

                    >> I noticed that thermal relief (spoke) widths are same for 0805 and

                    >> 0603, about 20 mils. For SOD-323 they are about 11 mils.

                    >> The width of GND polygon where they connect is 10 mils.

                    >>

                    >> Is that how it is supposed to be? How Eagle decides that?

                    >>

                    >> Thanks.

                     

                    Search for "Thermals" in the manual.

                     

                    In essence the spoke width is 25% of the drill diameter of the pad.

                    but between 1 and 2 wire widths of the polygon.

                    For a SMD I believe I read somewhere that it is based on the smallest

                    side of the SMD.

                     

                    Apologies, an error previously

                    Spoke width is 50% of the pad drill diameter or the smallest side of SMD

                    with a minimum width of 1 polygon wire width and a maximum of 2 wire widths.

                     

                    Warren

                     

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