track width change

Hi Ken,

Changing your net class rules so you can finish the routing isn't really the right way to do it in my opinion. Imagine, you come to make another change some weeks/months/years from now and you forget your changed the net class rule for the power. You press go on the auto router and it routes in a power trace much narrower than intended which for whatever reason goes unnoticed. You could end up with a problem on your board. Now, this may not be an issue for this situation because we have no knowledge of your circuit or requirements, but in general I would avoid doing things that could lead to errors at some point in the future.

Now, what Gerald says above, using power/ground planes is good advice, but sometimes this isn't practical, especially if you are trying to use 1 or 2 layer boards, but it's worth noting, but this could also be an issue with other high current nets other that just power/ground.

What I would say is that you maybe should reset your expectations for what the autorouter should be used for in reality. It is very rare that the auto router should be used for completely routing a board with no manual intervention, EAGLE's autorouter, as with pretty much every other vendors equivalent just aren't good enough to be able to do a complete board and have the finished result that would be 100% satisfactory, unless the board is really very simple e.g. a backplane with pretty much straight 1-to-1 routing.

I think of the auto router more of a routing assistant, so you use it to quickly put in sets of nets which are easy and obvious to route and would otherwise just be a long winded click fest to do manually. It's actually rare that I would do this as I pretty much route everything manually, but on occasion I do if it's obvious that the router will do a good job and it'll save significant time.

So back to your issue, I would sort out the breakout of the IC's manually first to get the traces out, decoupling caps connected up correctly with short traces etc and then try the auto router for the power/ground, then any other important signals and then finally the remainder of the board. I'd then go tidy up anything that was obviously messy from the autorouter and manually finish off anything it was unable to achieve.

Best Regards,

Rachael

Hi Ken,

Changing your net class rules so you can finish the routing isn't really the right way to do it in my opinion. Imagine, you come to make another change some weeks/months/years from now and you forget your changed the net class rule for the power. You press go on the auto router and it routes in a power trace much narrower than intended which for whatever reason goes unnoticed. You could end up with a problem on your board. Now, this may not be an issue for this situation because we have no knowledge of your circuit or requirements, but in general I would avoid doing things that could lead to errors at some point in the future.

Now, what Gerald says above, using power/ground planes is good advice, but sometimes this isn't practical, especially if you are trying to use 1 or 2 layer boards, but it's worth noting, but this could also be an issue with other high current nets other that just power/ground.

What I would say is that you maybe should reset your expectations for what the autorouter should be used for in reality. It is very rare that the auto router should be used for completely routing a board with no manual intervention, EAGLE's autorouter, as with pretty much every other vendors equivalent just aren't good enough to be able to do a complete board and have the finished result that would be 100% satisfactory, unless the board is really very simple e.g. a backplane with pretty much straight 1-to-1 routing.

I think of the auto router more of a routing assistant, so you use it to quickly put in sets of nets which are easy and obvious to route and would otherwise just be a long winded click fest to do manually. It's actually rare that I would do this as I pretty much route everything manually, but on occasion I do if it's obvious that the router will do a good job and it'll save significant time.

So back to your issue, I would sort out the breakout of the IC's manually first to get the traces out, decoupling caps connected up correctly with short traces etc and then try the auto router for the power/ground, then any other important signals and then finally the remainder of the board. I'd then go tidy up anything that was obviously messy from the autorouter and manually finish off anything it was unable to achieve.

Best Regards,

Rachael