According to http://referencedesigner.com/cal/cal_02.php, the conversion between "oz" and "mil" (thickness) for a PCB trace is 1.37. Also, according to
zcalc.exe (http://www.fedevel.com/welldoneblog/wp-content/uploads/2011/08/Zcalc.zip) 4.8mil correspond to 3.5 oz.
Now I get the following table from my foundry:
weight (cu) thickness (mil) 0.25 0.30 0.375 0.45 0.5 0.6 1 1.2 2 2.4 3 3.6 4 4.8
These numbers are off by quite a bit.
- How can this difference be explained?
Now I want to calculate the thicknes of my stripline (e.g. with the calculator referenced above).
- But which number should I use/trust from the table for my calculations? For example, for 4oz copper ... should I use 4.8mil should I use 4x1.37=5.48mil?
(I would tend to 4.8mil because the input to the stripline equations is thickness but I do not understand the discrepancy)