Re: FW: reactance of 0805 and smaller SMT resistors

nirmal@ansoft.com
Mon, 16 Jun 1997 10:27:22 -0400

Edlund, Greg wrote:
>
> > On Friday, June 13, 1997 7:45 PM, Eric Wheatley wrote:
> >>
> >> I would also like to point out that inductance is a property of a chip
> >> capacitor or resistor given a specific choice of terminals and a complete
> >> description of the conductive materials in the device. This is called
> >> partial inductance and it seems to cause a lot of confusion. No 'current
> >> loop' is needed; just the acceptance of the fact that the current magically
> > appears at one terminal and disappears into the other.
>
> I have to confess I am one of those who has experienced a great deal of
> confusion over the concept of "partial inductance." Would anyone care
> to
> take a stab at a physical definition of this quantity? I've seen
> equations
> that involve some pretty complicated line integrals, but perhaps there
> is a
> more down-to-earth definition that gets at the heart of the matter
> without
> getting bogged down in three-dimensional calculus. (Then again, perhaps
> there isn't...)
>

Hi Greg,

There is a good paper by Albert Ruehli, Brennan and Raver
of IBM published in I think early 80's which discusses the
concept of partial inductances and PEEC (Partial Element
Equivalent Circuits) method to compute inductances of planes,
and compares with analytical solutions.

The details of the paper are:-

"Three-dimensional Inductance Computation with PEEC"
Pierce Brennan, Normal Raver, Albert Ruehli
IBM Journal of Res and Dev, Nov 1979.

Hope it helps, Sincerely,

Nirmal


Nirmal Jain Ansoft Corporation
(412)261-3200 X29 (W) Four Station Sq., Suite 660
(412)261-471-9427(FAX) Pittsburgh, PA 15219
_______________________________________________________________________