Re: [SI-LIST] : stackup impedance.

Doug Brooks (doug@eskimo.com)
Mon, 29 Sep 1997 16:37:14 -0400

Case 1. The outer layers are simple microstrip layers; use
the formulas for microstrip. The inner layers are embedded
microstrip. If you download an impedance calculator from
UltraCAD, it has a screen for this and the formulas are in
the help file. Download ultraclc.zip from
www.ultracad.com (freeware)

Case 2. These are all assymetric stripline formulas. Use the
same calculator as above. When calculating the impedance for
any trace, ignore the others.

Doug Brooks

At 01:59 PM 9/17/97 +0800, you wrote:
>Hi,
>Does anybody have idea about how to calculate the impedance of
>stackup with following structures.
>
>S-S-G-P-S-S ( 6 layers).
>
>and
>
>G-S-S-S-S-P (6 layers).
>
>I checked books and tried to find equations to calculate impedance.
>However, I cannot find any.
>
>
>Best Regards,
>
>JOHNLIN
>CAE Engineer of EDA Department
>Digital Equipment Corp. Taiwan Branch
>Email: Linjohn@mail.dec.com
>TEL: 1-886-3-3900000 ext. 2565
>
>
>
>