I had a question about connecting the AGND and DGND on a 2 layer board. I see the sparkfun library has a component for this, however the pads are not connected (as i would assume this would correspond EAGLE to believe they are the same net). Not sure if they are connected on a layer I don’t have active or if need to manually route them together.
Thanks,
Alex
Connect them both to ground. Even if you need separate analogue and digital grounds for noise reduction, they need to be connected together at some point.
Leon
I will use two grounds on a board and keep them as different net names. This way you control where current returns paths are and where they are connected together. Leave them un-connected until all DRCs pass and the layout is completed. Then as the last step tie them together with a copper trace.
split ground planes are generally frowned on these days (for EMC reasons as much as anything). Some datasheets still have recommendations that are not best-practice.
When you do use split planes, you have to take a lot of care about return paths (and not creating large current loops due to the split). It is normally better to properly segregate analog / digital sections rather than put split planes.
Have a look at this; you have to register (free) but Keith’s advice is well worth it: