Re: [SI-LIST] : Trace Capacitance

Hans Mellberg (emcconsultant@yahoo.com)
Mon, 21 Jun 1999 17:38:10 -0700 (PDT)

two or more possible scenarios.
1) your trace widths are not exactly 5 or 20 mils. Over or under etch
could contribute to the error. Example, the 5 mil could have been 7
mils and the 20 mil could have been 17 mils.
2) Fringe field effects will make the 5 mil trace look a bit wider in
comparison to the 20 mil trace making the 4 to 1 ratio more like a 3 to
1 ratio. Fringe fields are more noticeable with thicker (1 or 2 oz)
traces than the thin (1/2 oz)traces.

===
Best Regards
Hans Mellberg
EMC Consultant
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