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EAGLE wire/pad oddity - any suggestions — Parallax Forums

EAGLE wire/pad oddity - any suggestions

Timothy D. SwieterTimothy D. Swieter Posts: 1,613
edited 2010-04-06 13:39 in General Discussion
I've been using EAGLE for a couple of years now. Overall I like and I like it even more as I learn the in and outs and started working with different scripts/ULPs. There is one item though I haven't found an answer for yet and thought the forum could help.

I attached an image. In the image there are two 1206 size caps. At the top of the right most cap you can see a trace that goes from a through-hole pin to the pad of the 1206. The thing I hate is how the wire, because of the thickness, overshoots the pad and there is a rounded edge sticking off the pad towards the interior of the components. Is there any way to prevent this overshoot? It looks ugly. In this case it isn't an electrical or clearance issue, but it could be in some designs.

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Timothy D. Swieter, E.I.
www.brilldea.com - Prop Blade, LED Painter, RGB LEDs, 3.0" 16:9 LCD Composite video display, eProto for SunSPOT, PropNET, PolkaDOT-51
www.tdswieter.com
EagleTest.JPG
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Comments

  • Erik FriesenErik Friesen Posts: 1,071
    edited 2010-04-05 11:17
    I run into the same thing using diptrace. Is your library the stock library? Your 1206 has a narrow pad compared to what I am used to. I will typically narrow that particular trace a bit. How many amps do you need on this trace?
  • Timothy D. SwieterTimothy D. Swieter Posts: 1,613
    edited 2010-04-05 11:22
    The library has been custom built. Some items are stock, some are made by hand following the prescribe standard for various components. The C10 cap in the image is for smoothing out large current draws, up to 400mA or more.

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    Timothy D. Swieter, E.I.
    www.brilldea.com - Prop Blade, LED Painter, RGB LEDs, 3.0" 16:9 LCD Composite video display, eProto for SunSPOT, PropNET, PolkaDOT-51
    www.tdswieter.com
  • Erik FriesenErik Friesen Posts: 1,071
    edited 2010-04-05 11:27
    I am like you, I like large traces to my caps. A calculator like this one says you only need a 10 mil width. Thoughts on that?

    www.4pcb.com/index.php?load=content&page_id=95
  • mctriviamctrivia Posts: 3,772
    edited 2010-04-05 13:16
    You can use a keepout area

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    Check out my brand new site.
  • Timothy D. SwieterTimothy D. Swieter Posts: 1,613
    edited 2010-04-05 23:15
    Erik Friesen - Thanks for the link to the calculator. There was another one I was also using and based on both of them I see my trace is larger, which I don't mind because in the calculators there are lots of parameters entered for which I could be off like ambient temps. The device could be used outdoors in an enclosure with the sun beating on it, which means the ambient will be much higher than room temps. So, I overbuilt it some. I'll keep the link you have close by, the Advance Circuit calculator is much easier to use than the one I was using.

    Mctrivia - Based on your suggestion I just tried keepout and restrict and neither one worked. I am guessing it is because keepout usually applies to copper pours and it doesn't apply with modifying wires. I tried restrict as well, but as it didn't work either. Thanks for the suggestion to check these out.

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    Timothy D. Swieter, E.I.
    www.brilldea.com - Prop Blade, LED Painter, RGB LEDs, 3.0" 16:9 LCD Composite video display, eProto for SunSPOT, PropNET, PolkaDOT-51
    www.tdswieter.com
  • mctriviamctrivia Posts: 3,772
    edited 2010-04-05 23:34
    Sorry thought you were using pore.

    Just shrink the width at the end of trace. So that trace is the size you want until just after the pad starts then really small afterwards

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    Check out my brand new site.
  • T ChapT Chap Posts: 4,249
    edited 2010-04-06 02:06
    Can you post that library part? That behavior doesn't seem right.
  • mctriviamctrivia Posts: 3,772
    edited 2010-04-06 02:53
    this is a very common problem with eagle and large traces to small pads.

    the simplest way is to remove the last trace and redraw it with the line tool. The line tool will not auto lock to the pads center like the trace tool will. the line should connect itself to the trace as long as you start where you left off on the trace. if not manualy rename.

    doing this will leave a small unrouted line showing. to remove this use a really small trace(As small as your board rules will allow) to finish off to the pads center.


    the harder way is to split the trace then use the resize tool to resize the last section to be really small. sounds easy but not always easy to do.

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    Check out my brand new site.
  • Timothy D. SwieterTimothy D. Swieter Posts: 1,613
    edited 2010-04-06 13:39
    Mctrivia - I like your idea about redrawing with the line tool and I will try that tomorrow as it is too late for me to tinker with it tonight.

    Earlier today I was looking into the "cap" parameter. I believe it said round or flat. I wasn't able to change the routed wire to flat. Come to think of it I don't know that I have seen any EAGLE lines - wires or otherwise - without a rounded edge.

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    Timothy D. Swieter, E.I.
    www.brilldea.com - Prop Blade, LED Painter, RGB LEDs, 3.0" 16:9 LCD Composite video display, eProto for SunSPOT, PropNET, PolkaDOT-51
    www.tdswieter.com
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