PCB Routing Questions

Thread Starter

mcardoso

Joined May 19, 2020
226
I really appreciate everyone's help here - learning tons!

I've only ever done very simple boards before with obvious routing requirements. This one threw me for a loop!

I feel like I was playing a bad game of snake for a few hours trying to route this board. I got a little off course and finally realized that my tactic of routing as much as possible on the top layer and then bumping to the bottom only when necessary. This quickly turned the bottom into a tangled mess and I couldn't make any of my long connections.

So I ripped all of it off and tried the auto router with a 10/10 spacing for all traces (I routed differential pairs and my power circuitry before running the auto router). It finished quickly and 20 or the 24 attempts finished with 100%. I see now why people say vertical on the top layer and horizontal on the bottom. It doesn't block you from running longer traces!

I picked one of the designs with the cleanest look and fewest vias. I added a bunch of additional vias to stitch the ground planes on the top and bottom together and rerouted some of the traces to make it look cleaner.

The few times I did this in college, I always heard people telling me not to use autorouting, but I think it did a better job than I was going to without having to drop down to a lower trace size.
 

jpanhalt

Joined Jan 18, 2008
11,087
I also use Eagle and have since v.3.x. In any discussion of "how to/should," it is helpful to know the software being used.

Edit: I didn't see your post #21 before responding. I do something similar to what you describe. I will manually route critical units, such as connections to a digital thermocouple amplifier. Then try an autorouter to get (maybe) a better idea for some other areas. In the final design, I generally manually route everything. That's helpful when I want to increase track size or minimize length, as for VCC.
 
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Thread Starter

mcardoso

Joined May 19, 2020
226
Here is the auto-routed board. I still need to clean up some thing and add more stitching vias, but it is 100% routed.

1592320665831.png
 
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