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Pad Seed Points

melview1

Using OrCAD PCB Designer v16.3.S009 

I would like to know how to control the copper seed point on a particular symbol, but not the whole design.

I have a shield over a part that has 4 pads that are all GND.  This part is on the top layer which has a GND copper pour dynamic shape.  When I smooth the shapes, it makes very odd angled connections between the pads and the pour even though my global dynamic shape thermal relief parameters are set to orthogonal.  It puts in a 5 mil relief around the pad except for 3 points at which it runs a cline from the origin of the pad to the pour.  I would like to allow the copper pour to flood to these pads without a thermal relief and therefore no odd angled lines.  However, I don't want this to happen to all of the parts on the designs that connect to GND.  I like those the way they are.

 Any ideas?  Thanks.

 

--Mark

  • Rik Lee

    You can add the instance property to each pin. Edit >Properties; select the pin(s) and add:

     DYN_THERMAL_CON_TYPE = FULL_CONTACT

    This will provide a full contact (no thermal ties) to each of the pins.

  • Goblin59

     Rik,

    Does this work in Allegro also?

    Cheers,

    Ron Scott CID+

  • Rik Lee

     Hi Ron,

    Yes, these pin instance properties can be applied in Allegro.

       DYN_CLEARANCE_OVERSIZE =
       DYN_CLEARANCE_TYPE = DRC_VALUE/ANTI_THERMAL/NO_VOID
       DYN_FIXED_THERM_WIDTH = <overrides contraint line value>
       DYN_MAX_THERMAL_CONNS =
       DYN_MIN_THERMAL_CONNS =
       DYN_OVERSIZE_THERM_WIDTH = <in addition to your constraint line value>
       DYN_THERMAL_BEST_FIT = TRUE/FALSE
       DYN_THERMAL_CON_TYPE = FULL_CONTACT/DIAGONAL/ORTHOGONAL/8_WAY/NONE
       
       
    The following can also be applied at the shape instance level as well overriding what you have for your global dynamic shape parameters. The can be found when selecting the shape and then using the right mouse button to select shape parameters. Pin properties will override both shape instance and global paramaters.
       
       DYN_THERMAL_CON_TYPE - Can be applied differently depeing on pin type (via/smd pins/thru pins
       MIN/MAX CONNEXTIONS - Also applied per pin type
       FIXED THERMAL WIDTH
       THERMAL WIDTH OVERSIZE
       CLEARANCE TYPE - DRC/THERMAL or ANTI applied per pin type
       OVERSIZE VALUE - Applied per pin type
       
    Hope this helps,

    RIk

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