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    Recomended grounding methods of Analog ground and ground plane

    Hello everyone,
    I am preparing a two layer PCB where I need to put a circuit producing negative voltage for Op-amp. The recommended design of the IC (ADP5070) which I am using strictly says to separate power ground and analog ground separate. My question is how should I connect Analog ground and ground plane, should I put a 0ohm resistance to it? And If not required to put the 0ohm resistor in the circuit then how to draw it in schematic. I am using EAGLE tool for schematic and PCB. Here is my design for negative power supply.Click image for larger version. 

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    An PDF of the IC I am using for the negative power source.negative_source_adp5070.pdf.

    Please comment if I have not provided enough details.

    Thank you.

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    Re: Recomended grounding methods of Analog ground and ground plane

    Have you seen the page 26 of the datasheet?
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    Re: Recomended grounding methods of Analog ground and ground plane

    Your schematic has wrongly connected the exposed pad to PGND, should be AGND.

    The connection between AGND and PGND is usually made by PCB copper or vias. To design it straightforward in PCB tool, you need specific features like start points or net connectors that can be placed in layout. As far as I remember, Eagle doesn't have it. SMD jumpers are a possible solution, I personally prefer copper "bridging" on a separate design layer that is merged with regular copper layer in post process, if the PCB tool has no native support for net connectors.



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    Re: Recomended grounding methods of Analog ground and ground plane

    Quote Originally Posted by ZASto View Post
    Have you seen the page 26 of the datasheet?
    Yes, I have read the document. I am not a professional PCB designer. Its my first PCB. The third bullet point of page 26 says all of this. In eagle I am doing autoroute and then creating a copper layer of GND. If somehow I manage to remove the auto-routed connections of this IC and do it manually. What should I do? Will I go with the same trace what the datasheet had provide?

    Please guide me whether I am understandable to you.

    - - - Updated - - -

    Quote Originally Posted by FvM View Post
    Your schematic has wrongly connected the exposed pad to PGND, should be AGND.

    The connection between AGND and PGND is usually made by PCB copper or vias. To design it straightforward in PCB tool, you need specific features like start points or net connectors that can be placed in layout. As far as I remember, Eagle doesn't have it. SMD jumpers are a possible solution, I personally prefer copper "bridging" on a separate design layer that is merged with regular copper layer in post process, if the PCB tool has no native support for net connectors.
    Sir, I did not get your explanation. I but I think you are right. In eagle the AGND and GND are never connected and are treated as separate net. Can I go with a 0ohm resistor to connect both the AGND and ground plane?



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    Re: Recomended grounding methods of Analog ground and ground plane

    Can I go with a 0ohm resistor to connect both the AGND and ground plane?
    That's possible.

    In eagle I am doing autoroute and then creating a copper layer of GND.
    I doubt that you can achieve reasonable routing of the power circuit with Eagle auto router.



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