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PCB slots connectivity query

Former Member

I'm attempting to use plated through slots on a double sided PCB for a micro HDMI connector. The connector uses slots to solder its shield to the PCB. The shield is connected to a portion of the PCB I've called the 'chassis' ground plane.  This 'chassis' ground a poured copper plane is on layer 16 under the connector.  It's separate from the ground plane on the rest of the top and bottom of the PCB as it's intended to create an EMI barrier.

I've created slots for the connector by drawing an outline on the milling layer 46. The slot is an oblong figure about 0.7mm wide by 1.3mm long with a 0.3mm annulus.  However unlike pads or vias this figure doesn't have any electrical connectivity to either the top or bottom layers.  Is there a way to add this?  Or is there a way to create a pad to look like a slot?

So that there is some schematic connectivity to the shield I've placed pads within the slots but this does't give me a connection from the top to the bottom layer like a pad forming a plated through hole.

On the top layer I want to be able to take a track to the plated through slot and have it electrically connect though the plated slot to the chassis ground.  I've not found a way to do this other than add vias but there really isn't any room for them and it seems a shame to have to add them just to get rid of airwires when I know the electrical connectivity I need will be made though the plated though slots.

  • 0

    Hi,

    I've created slots for the connector by drawing an outline on the milling layer 46. The slot is an oblong figure about 0.7mm wide by 1.3mm long with a 0.3mm annulus.  However unlike pads or vias this figure doesn't have any electrical connectivity to either the top or bottom layers.  Is there a way to add this?  Or is there a way to create a pad to look like a slot?

    So that there is some schematic connectivity to the shield I've placed pads within the slots but this does't give me a connection from the top to the bottom layer like a pad forming a plated through hole.

    If i understand your need is a oblong plated through hole. As explain in manual, you have to place a through hole pad (drill size = the lower diameter of the oblong), and connect this pad to a pin of your symbol. You can also use a SMD pad.

    the general rules is that is you put a pad (TH or SMD) inside a copper area (polygon) in lbr, then Eagle will consider that the copper area will be connected to the pad...

  • 0 in reply to kikoun

    Thanks for your help.  I tried placing a TH within a polygon in Eagle V5.11 and it didn't work so I abandoned that approach.  However after reading your suggestion I upgraded to 7 re-did the library package and indeed the polygon on layer 1 did assume the connectivity of the through hole pad within it.  For those reading this just a side note that while the polygon is now electrically associated with the through hole or  SMD pad Eagle doesn't  automatically generate a solder mask surrounding the polygon as it does for TH orSMD pads.  You will need to do this manually for the package (can be done within the library).

  • 0 in reply to Former Member

    Hi,

    For those reading this just a side note that while the polygon is now electrically associated with the through hole or  SMD pad Eagle doesn't  automatically generate a solder mask surrounding the polygon as it does for TH orSMD pads.  You will need to do this manually for the package (can be done within the library).

    That's not an issue for me since I rarely need to have the same shape and/or dimension for copper, solder mask and cream. Some time I need a copper defined pad (copper is smaller than solder-mask), sometimes it a solder-mask define pad (solder-mask is smaller than copper).

    And some time, the copper area as nothing to do with the solder-mask and cream (for dissipating pad for example, or for fixing SMD connector pad)...

    So I prefer to draw the solder-mask and the cream myself, according to my needs (or our contractor's ones).