[sdiy] Eagle analogue & digital groundplanes

[rsdio at audiobanshee.com]

I typically place an 0805 inductor link between analog and digital ground, near the analog supply regulator. In some cases, I've had to change the BoM from inductor to resistor or jumper. I think that placing the SMD pads there, in 0805 sizing, is a good step no matter how you connect the grounds.

Professional layout engineers seem to do a lot of manual work, in which case I'd imagine that they just live with the DRC violations.

I've read articles which claim that separate ground planes are not necessary - when placement and ground paths are properly controlled. However, I like to have the separate ground planes anyway, because it at least gives me a reminder of the ground paths that I've planned during placement. These articles talk about lots of stitching via links between layers for multiple ground planes, but that's only an option when you have the luxury of more than four layers, I'd say.

Brian Willoughby
Sound Consulting


On Nov 25, 2015, at 8:18 AM, Richie Burnett <rburnett at richieburnett.co.uk> wrote:
> Out of interest what are Eagle PCB CAD users doing to connect together their analogue and digital ground-planes?
> 
> A wire-link, 0805 zero-ohm link, or over-lapping the polygons for the analog and digital ground-planes and accepting a DRC violation at the point where they're connected?
> 
> Those are the best ideas I had, but wondered if there's a clever way to do it.