I'm looking for some guidelines.
I have 15 mil trace that runs parallel to another 15 mil trace for about 1 inch and there is only about 10 mil separation between them.
One of these lines is power rail which has about 25mA through it, but according to my simulation it's oscillating by a fraction of a milliamp at a few kilohertz. Simulations are one thing but I bet for real the oscillation is more severe.
Unfortunately the other line is a signal line, which is a disaster! I understand the theory pretty well, the flux lines will be normal to it, it depends on distance and the flux density rate of change (and loop area I think), but anyway, my PCB is no good and has to be redesigned because the parasitic coupling is really bad.
What do the guys think here when you're doing a line level audio pcb, what clearances between these kind of tracks do you observe in your layout etc.
The thing is this kind of thing you can't spot the problem in breadboarding and sure won't show up in your SPICE, you can only spot and avoid stuff like this with experience.
When I redesign my PCB I'm not sure how far apart to move the power rail from the signal rail and I'm wondering what if the power rail runs close to just one through hole soldered joint which is of course just a small circle of 3 mm, I wonder if that will pickup the contamination too.
I can only tell by redoing the PCB and then even my next PCB may still have the problem. I'll be happy to hear any tips from you all.
I have 15 mil trace that runs parallel to another 15 mil trace for about 1 inch and there is only about 10 mil separation between them.
One of these lines is power rail which has about 25mA through it, but according to my simulation it's oscillating by a fraction of a milliamp at a few kilohertz. Simulations are one thing but I bet for real the oscillation is more severe.
Unfortunately the other line is a signal line, which is a disaster! I understand the theory pretty well, the flux lines will be normal to it, it depends on distance and the flux density rate of change (and loop area I think), but anyway, my PCB is no good and has to be redesigned because the parasitic coupling is really bad.
What do the guys think here when you're doing a line level audio pcb, what clearances between these kind of tracks do you observe in your layout etc.
The thing is this kind of thing you can't spot the problem in breadboarding and sure won't show up in your SPICE, you can only spot and avoid stuff like this with experience.
When I redesign my PCB I'm not sure how far apart to move the power rail from the signal rail and I'm wondering what if the power rail runs close to just one through hole soldered joint which is of course just a small circle of 3 mm, I wonder if that will pickup the contamination too.
I can only tell by redoing the PCB and then even my next PCB may still have the problem. I'll be happy to hear any tips from you all.