Why are 90° angled traces bad?
colhany , 03-26-2022, 08:08 AM
Is there a scientific or practical reason why we avoid 90° traces? I have heard Robert and a lot of other experienced PCB designers say that they should be avoided. But according to Lee Ritchey, the fact that they cause reflections is a myth. So what is the real reason?
Thank you
robertferanec , 04-04-2022, 03:16 AM
My opinion - Electrically it may not be a problem for standard boards, However:
- it may not be practical to use 90Deg, it may need more space for layout (a diagonal is shorter than a horizontal + vertical line)
- if you use 90deg, other engineers may comment on it (many comments may be negative and say it is a bad layout)
- when you have a look around, designs normally do not use 90deg corners
so I simply don't use them
qdrives , 03-26-2022, 05:10 PM
According to Rick Hartley it starts to be a (little) problem at multiple GHz frequency. So that is the scientific part.
Practically you might consider acid trap, but that too should be at angle > 90
"But we learned it that way"
suleymancskn , 03-28-2022, 03:59 AM
robertferanec , 04-04-2022, 03:16 AM
My opinion - Electrically it may not be a problem for standard boards, However:
- it may not be practical to use 90Deg, it may need more space for layout (a diagonal is shorter than a horizontal + vertical line)
- if you use 90deg, other engineers may comment on it (many comments may be negative and say it is a bad layout)
- when you have a look around, designs normally do not use 90deg corners
so I simply don't use them
colhany , 04-04-2022, 03:26 AM
Thank you everyone
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