17 Jun
2017
17 Jun
'17
9:17 a.m.
On Fri, Jun 16, 2017 at 8:40 PM, mike.valk@gmail.com mike.valk@gmail.com wrote:
Bleh. It looked so pretty in my mind. ;-(
i knoow... btw can you possibly investigate why, when you hit "reply", the ">"s are not added?
So different layers have different copper thickness.
in a stack you tell the factory what thicknesses you want, as well as what material in between, and what thickness of that, too. so you get different capacitance on different layers. thus, the problem is: you cannot guarantee the impedance will be identical on different layers. so having differential pairs on different layers is the worst possible thing you could do.... *unless* you have access to PCB simulators. which are ultra-expensive.
l.