Changing Line Width of a Trace in a Net without DRC Errors

Hi Excellon1,

I thought changes to the Edit Property window in the editor are local changes that overwrite the global settings in the constraints manager for the selected object only. In my case they cleared the errors with 8mils for that trace but 100mils setting is still in the constraints manager. This is why a document explaining the inter-working relationships of all these settings would be great.

I will try the necked routing as you and Redwire suggested and see how that goes.

Once again, thanks for your help. You guys are great. 

TC

Hi Redwire,

Thanks for the demo files. That works for me.

What I notice is that a trace has to contain at least a segment of 100mils. Otherwise, I have the same errors. I guess they stay true to the meaning of a necked trace.

In your file, if I delete the last trace segments to R1 and R2, this turns into a connection between these two. If I use Neck Mode to route this connection end to end, this 8mils trace has these same errors. In my design, these are long winding traces. Following the same concept, I have to find a spot for each trace to drop a 100mils segments somehow. It's going to look like pythons after having big meals.

It would be great to have a clean way of doing this, just 8mils traces. If not, I guess I just waive these errors and done with?.

TC

Neck rules will very much depend on what is touching the necked cline.  In my example I set an arbitrary neck length that might not work for all cases.  If you could alter my example and post it back with what issues you're running into I think we can figure out the right rules that don't require waiving.

Hi Redwire,

I have been fooling around with your file by deleting routes, moving the Rs around, re-routing them in Neck Mode end to end and partial, routing back on the main trace and branch off and so on. I think the solution is the value set for Neck Max Length as you suggested. It was a bit confusing at first because the errors remained even though it was changed from 500mil to 5000mils in the constraints manager. I had to touch the trace to clear them. I guess it does not clear the errors automatically after each change.

I will use this Neck Max Length setting to finish what I was working on. I still have some other errors like pad to trace at the ICs to figure out. I think they relate to this somehow. Maybe I have to touch those traces to clear those errors. If I need help for that, I will continue with this tread instead of creating a new one so info does not get repeated.

In all, I thank you and Excellon1 for the help.

TC

Hi TC. Another approach to all of this would be one of an electronic approach. Since you have a main bus line that is feeding down stream logic, I propose splitting the net.

To feed the logic off the main branch you could use a small ferrite  bead or a zero ohm jumper-Resistor. This would resolve those net issues for you.

It may help with EMI in the case of the ferrite or the zero ohm jumper-resistors can act as a fuse if one of the downstream logic should fail. We routinely do this for all power distribution to down stream regs and it works pretty good.

Maybe an idea to consider.

All the best.