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 Allegro Padstacks; Defined Geometry vs. Flash 

Last post Wed, Jan 24 2007 11:05 AM by archive. 3 replies.
Started by archive 24 Jan 2007 11:05 AM. Topic has 3 replies and 987 views
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  • Wed, Jan 24 2007 11:05 AM

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    Allegro Padstacks; Defined Geometry vs. Flash Reply

    Ok Allegro, here's a question from my boss.

    Why is it that you can get WYSIWYG on a Thermal flash, but if you put a flash symbol in the Regular column of a padstack, you see the defined geometry?
    Here's my example. I have a special flash I use for a bottom solder paste, but if I want to see that shape in Allegro, I cannot (at least not WYSIWYG). But by entering a flash name in the same Flash cell under the Thermal Relief column, I can see my thermal shape.
    What up?
    Any improvements for this coming in V16.*? Enlightenment from the list?

    Thanks

    Andrew


    Originally posted in cdnusers.org by annoonan
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  • Thu, Jan 25 2007 10:21 AM

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    RE: Allegro Padstacks; Defined Geometry vs. Flash Reply

    Andrew,

    For most cases you would enter your special geometry for a Regular Pad in the Shape Field. 

    If your special geometry for the Regular Pad consists of multiple shapes then you would enter the name in the Flash Field inside of the padstack and provide detailed information of the geometry along with your gerber files (which will not give you WYSIWYG inside of Allegro. 
    To avoid the extra documentation for this special geometry I would recommend using the Shape Field vs Flash Field for Regular Pad definitions and find a way to join the multiple shapes together if they exist in your special geometry. 
     
    Attached is an example of a TO-263 which has a special solder paste which required four square solder paste pad islands instead of one large solder pad but to get WYSIWYG and to avoid the extra documentation at Gerber time they have been joined together to make one shape which could be entered in the Shape Field.


    Originally posted in cdnusers.org by mcatramb91
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  • Thu, Jan 25 2007 1:57 PM

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    RE: Allegro Padstacks; Defined Geometry vs. Flash Reply

    Hey Michael, thanks for the response and picture. Workarounds are ok, and I suppose I could do something like this but I was thinking more about a consistent approach to methodology within the software.

    Just complaining, to see what's out there. :o)

    Andrew


    Originally posted in cdnusers.org by annoonan
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  • Thu, Jan 25 2007 2:37 PM

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    RE: Allegro Padstacks; Defined Geometry vs. Flash Reply

    Agreed. Just to give you a little more background..

    The Flash Field always worked the same way across the three Pad types (Regular/Thermal/Anti-Pad) until Cadence rolled out support for RS274X which required embedded Flash features which need to reference the library for its geometry during data generation. As part of the migration to RS274X they added controls to view these flash geometries WYSIWYG on Negative Planes but I guess they never thought users would be using Flash Geometries on anything other then Negative Planes thermal reliefs. Back then WYSIWYG Negative Planes was a hot-button issue but not so much now with the Dynamic Shape functionality.

    I don't think there is anything on V16.0 that changes the way it is handled. I would submit an Enhancement request with Cadence and who knows it may be an easy fix.

    Any other opinions out there ?


    Originally posted in cdnusers.org by mcatramb91
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Started by archive at 24 Jan 2007 11:05 AM. Topic has 3 replies.