regards
weber
SI Eng.=20
VIA Tech. =20
> -----=AD=EC=A9l=B6l=A5=F3-----
> =B1H=A5=F3=AA=CC: Joachim Mueller [SMTP:[email protected]]
> =B6=C7=B0e=AE=C9=B6=A1: 1997=A6~9=A4=EB19=A4=E9 =A4W=A4=C8 12:35
> =A6=AC=A5=F3=AA=CC: John Lin - TAO
> =B0=C6=A5=BB: [email protected]
> =A5D=A6=AE: Re: [SI-LIST] : stackup impedance.
>=20
> Hi,
> I am a fan of numerical field solver too. I have no doubt that the
> results are accurate. But the problem is that the PCB manufacturing
> process is not as accurate as the field solver is. There are =
parasitic
> parameters involved which are usually not considered in simulation
> models.=20
>=20
> If the stackup has two or more adjacent signal layers, the coupling
> between=20
> the traces on different layers is hard to model but will influence =
the
>=20
> characteristic impedance. It is certainly not the case that you want =
a
> strong=20
> coupling between all four signal layers (second stack up) by routing
> them on=20
> top of each user.
>=20
> >From all that, we found that the most accurate is to get an =
empirical
> data base (measurements) from the board shop.
>=20
> Joachim
>=20
> --=20
> =
+---------------------------------------------------------------------
> +
> | voice: +1 613 591 3600 | Joachim Mueller, EMC-Approvals
> |
> | fax : +1 613 599 3654 | 600 March Rd. P.O. Box 13600
> |
> | e-mail: [email protected] | Kanata, Ontario, (CA) K2K 2E6
> |
> =
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> +
> | Newbridge Networks Corporation
> |
> |
> |
> | __o
> |
> | _`\<,_
> |
> | (_)/ (_)
> |
> | ~~~~~~~~~~
> |
> =
+---------------------------------------------------------------------
> +
>=20
>=20
> >=20
> > Hi,
> > Does anybody have idea about how to calculate the impedance of
> > stackup with following structures.
> >=20
> > S-S-G-P-S-S ( 6 layers).
> >=20
> > and
> >=20
> > G-S-S-S-S-P (6 layers).
> >=20
> > I checked books and tried to find equations to calculate impedance. =
> > However, I cannot find any.
> >=20
> >=20
> > Best Regards,
> >=20
> > JOHNLIN
> > CAE Engineer of EDA Department
> > Digital Equipment Corp. Taiwan Branch
> > Email: [email protected]
> > TEL: 1-886-3-3900000 ext. 2565
> >=20
> >=20
> >=20
>=20
>=20
>=20
>=20