[SI-LIST] Re: 10-Layer Stack up

Serious question - is a superconductor non-inductive?  Just curious...

Regards,
 Stephen Peters
 Intel Corp.


-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]
On Behalf Of Muranyi, Arpad
Sent: Monday, May 23, 2005 12:04 PM
To: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Re: 10-Layer Stack up

Couldn't someone finally invent a non-inductive
conductor?!?!?  - Just a joke...   :-)

Arpad
=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D=
3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D
=3D3D=3D
=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D=
3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D

-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]
=3D On Behalf Of steve weir
Sent: Monday, May 23, 2005 11:55 AM
To: tmcgonigle@xxxxxxxx; sunil_bharadwaz@xxxxxxxxx; =3D
si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Re: 10-Layer Stack up

Thomas, contrary to popular folklore, the main benefit of a thin =3D
sandwich=3D20 is not more capacitance but lower inductance.

If you have any doubts, consider that with a high Er dielectric you =3D
could=3D20 achieve equivalent plane cavity capacitance with a much =
thicker
=3D dielectric=3D20 but also much higher inductance.  I believe that if =
you
model that, it =3D will=3D20 become clear to you that Larry Smith's =
battle
cry:  "It's the inductance =3D

stupid!" is on the mark.

It is low inductance that presents a low impedance to high=3D20
frequencies.  The planes present a lower inductance than the bypass=3D20
capacitors, but for it to be useful as a shunt on its own through =
the=3D20
cavity capacitance, you have to cross the AR created by the cavity with
=3D the=3D20 discrete bypass capacitors.  Because of the problems that
presents we =3D have=3D20 seen many proposals to try and find better
damping, whether it be any of =3D

the resistive techniques or high ESR capacitors that Istvan has =3D
proposed,=3D20 or raising the net ESR of the discrete network using
Larry's F^N=3D20 technique.  Since by and large most people do not use =
any
of the =3D techniques=3D20 either Istvan or Larry have proposed to solve
that problem, they live =3D with=3D20 it for better or for worse.  Under
those conditions, more capacitance =3D can=3D20 be as much of a problem =
as
it can be a benefit.  But lower inductance =3D helps=3D20 no matter =
what.

Steve.
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