I just got my E-Series evaluation kit and finally started trying to do a surface mount layout - so I took a look at the Eagle layout and wow…
It’s not clear to me why you have such an intense ground plane arrangement since the Electron doesn’t seem to have any high frequency issues. The layout I’m currently using for the Electron is very simple and seems to work flawlessly with a 2-layer board where the bottom layer is mainly ground plane but without much in the way of inter-vias. Are there concerns with the E-Series and radiation under the chip or are you just using a ‘stick vias everywhere’ arrangement? Are you just worried about stuff coming back up into the chip? Is there any hope of using this with a 2 layer board?
I also don’t get the pins on the bottom of the chip. I’d like to hand-solder my first few prototypes but that’s fundamentally impossible when you have three ground connections inside the chip boundary on the bottom. It looks like the prototype layout doesn’t connect to them but I could be missing something.
What’s the deal with the various ground pins? Is the assumption that we connect to them if we want or must we connect to them? Even on the Electron you have two ground pins and I’ve never understood if one or both should be connected to the ground plane. Both seems wrong fundamentally but ?