[SI-LIST] : 回覆 : [SI-LIST] : stackup impedance.

Weber Chuang (WeberChuang@via.com.tw)
Fri, 19 Sep 1997 10:18:21 +0800

Yes, I do totally agree, and that's what we are doing right now in my
corp.. However, simulation should be used to help the speeding up of
design cycle, so we are trying to make a correlation between
simulations and empirical data base which we think might help us in the
future development. So is there anyone has ever tried such approach?
If Yes, is there any particular step that needs to be taken care of? =
Can
you talk about this?

regards
weber
SI Eng.=20
VIA Tech. =20

> -----=AD=EC=A9l=B6l=A5=F3-----
> =B1H=A5=F3=AA=CC: Joachim Mueller [SMTP:jmueller@ca.newbridge.com]
> =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: si-list@silab.Eng.Sun.COM
> =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
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> 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
> =
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>=20
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> >=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: Linjohn@mail.dec.com
> > TEL: 1-886-3-3900000 ext. 2565
> >=20
> >=20
> >=20
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