Re: About AGND and DGND
If in a circuit you have both analog and digital signals it is always good practice to separate AGND from DGND. PCB layout should also separate A from D.
In some data sheets you can read: "For best results connect the grounds together at a single point with a 0.050 inch trace..."
This trace acts infact as an inductor, so if you prefer to use copper trucks, breads or RF-chokes it is your choice, but I think that separation is good engineering practice..