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Problem connecting Power Pads to GND polygon

autodeskguest

I am designing a board that includes several kinds of ICs

with "Power Pads" under the IC package that need

to be grounded.  For some of the ICs, the GND polygon

connects to the Power Pad as it should.  For other

ICs, the GND polygon is not connecting to the Power Pad.

Examining the devices in the library, they appear to be

constructed and labeled the same way.  I can't see

a difference in labeling, pin declaration, or grounding

between the ones that connect to ground and the ones

that don't.

 

Can you suggest what might be different between the

ICs or the libraries to cause this?

 

Thank you,

--- Graham

 

==

 

Parents

  • On 10/11/2009 10:49 PM, Graham wrote:

    I am designing a board that includes several kinds of ICs

    with "Power Pads" under the IC package that need

    to be grounded. For some of the ICs, the GND polygon

    connects to the Power Pad as it should. For other

    ICs, the GND polygon is not connecting to the Power Pad.

    Examining the devices in the library, they appear to be

    constructed and labeled the same way. I can't see

    a difference in labeling, pin declaration, or grounding

    between the ones that connect to ground and the ones

    that don't.

     

    Can you suggest what might be different between the

    ICs or the libraries to cause this?

     

    Thank you,

    --- Graham

     

    ==

    My first thought is, do the gnd pads of the package have air-wires in

    the PCB editor? If so, check the Isolate property for the polygon to get

    them to connect.

     

    If there are no air-wires, I'd suggest checking the Direction and Name

    properties of the symbol's pin. Make sure Direction = Pwr, and that Name

    = GND. That usually does it for me...

     

    Travis

     

Reply

  • On 10/11/2009 10:49 PM, Graham wrote:

    I am designing a board that includes several kinds of ICs

    with "Power Pads" under the IC package that need

    to be grounded. For some of the ICs, the GND polygon

    connects to the Power Pad as it should. For other

    ICs, the GND polygon is not connecting to the Power Pad.

    Examining the devices in the library, they appear to be

    constructed and labeled the same way. I can't see

    a difference in labeling, pin declaration, or grounding

    between the ones that connect to ground and the ones

    that don't.

     

    Can you suggest what might be different between the

    ICs or the libraries to cause this?

     

    Thank you,

    --- Graham

     

    ==

    My first thought is, do the gnd pads of the package have air-wires in

    the PCB editor? If so, check the Isolate property for the polygon to get

    them to connect.

     

    If there are no air-wires, I'd suggest checking the Direction and Name

    properties of the symbol's pin. Make sure Direction = Pwr, and that Name

    = GND. That usually does it for me...

     

    Travis

     

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