[SI-LIST] Re: Inductance of Via
- From: "Tsuk, Michael" <Michael.Tsuk@xxxxxxxxxx>
- To: si-list@xxxxxxxxxxxxx, cnepsc@xxxxxxxxxxxxxxx
- Date: Wed, 13 Jun 2001 10:24:24 -0500
Neeraj Pendse wrote:
<<
I disagree with Michael's statement that it does not make sense to talk
about
the inductance of the via in isolation. While I agree to the fact that
the
entire current "loop" must be considered when you are minimizing the
inductance
- the concept of inductance is not limited to "loops", bet can also be
applied
to discreet pieces of a loop. When all significant mutual inductances
are
accounted for, the total inductance of the loop can be easily realized
from
the pieces. This is the concept of "partial inductance", and in my
opinion it
is a very powerful method of evaluating interconnects when you want to
do a
lumped element analysis.
>>
I think we're actually in agreement here. You say that "when all
significant mutual inductances are accounted for", you can use partial
inductances to get the right answer. All I'm saying is that, in the via
problem, there are significant mutual inductances, the ones between the
signal via and the return path. Without considering them, the partial
inductance of the via by itself is meaningless. It's not even a good
approximation to the total loop inductance, except by accident, because
the mutual partial inductances to neighboring vias are of the same order
of magnitude.
Partial inductances can be a useful tool, but one sees them misused
almost as often as one sees them used correctly, and this is a perfect
example.
--
Michael Tsuk
Compaq AlphaServer Product Development
(508) 467-4621
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List archives are viewable at: //www.freelists.org/archives/si-list
Old list archives are viewable at: http://www.qsl.net/wb6tpu
Other related posts:
