Copper Pour won't connect to Ground Pads

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I put a copper pour on my top layer. That copper pour is a ground net. Some of my pads gets connect to this copper pour. However, others don’t and I have to create a bridge with vias (see blue arrow in the pic) for connections to be made. Does anyone know why ?

I managed to have all nets connected, but I just want to know why I have to create these ‘via bridges’ when I have a copper pour connected to ground net.

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You have created two isolated islands of copper by virtue of the clearances around the AD0, AD1 and AD2 pins.

Accordingly, those islands are not connected to ground, and the capacitor will not automatically connect to such an island to achieve grounding.

Simple alternatives (there are many ways to do it) include

  1. rotating C5 180 degrees, so it connects to the larger ground connected copper pour, and either
    2a) bridge C4 across the AD0 track going to C5 to connect to the ground pour, or
    2b) decouple AD1 with a trace travelling past AD0 or on the underside of the board to a via and connect C4 there and thence to the larger copper pour, enabling you to eliminate the isolated islands completely.

If you will be making a two layer board, then options for routing increase.

In addition,

The track for 2.5V bus could be achieved with a via and a track on the other side of the board to the 2.5V shield pin, avoiding the need to have a high impedance bridge across the copper pour between U2 and C2.

Similarly, the 5V bridge could be made longer to keep more of the copper pour intact between U1 and C5, making it a better ground plane.

Cheers,

Erich.

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Thanks for the answer. I am a noob in PCB laying out. That is now apparent that there was an island.

I am making a two layer board, so I will try to route ADO, AD1 and AD2 on the bottom layer to avoid this island.

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Bunch the tracks together, to not get those islands in the first place.
C4 can have a track going underneath it on the same side (front), so you don’t need to ‘jump’ with the GND to it.

Also, if you move U2, C1 to the left bottom of the board you can get rid of that 5V jumping over the other tracks as well.

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