RE: [IBIS] Question in R, L, & C Matrix

Yasser,

Thanks for your question. 

R_pin, C_pin, etc. are intended to represent package parasitics where
coupling effects are not of interest.  The matrix keywords, on the other
hand, were added specifically to represent conductor-to-conductor
package coupling for a component in an IBIS file.  

Are you trying to use discrete elements, including the [Pin] package
parameters, to represent a coupled transmission line system?  You may
run into some trouble doing this directly.  For example, C_pin is the
capacitance of the pin by itself with respect to the (assumed) reference
node for the circuit.  However, the [Capacitance Matrix] is in
Maxwellian format, where Cnn is the sum of the capacitance to the
reference plus the mutual capacitance to the surrounding lines (i.e., as
if all the other lines were grounded).  Cnm is the mutual capacitance
between lines n and m (and in Maxwellian format, the off-diagonal
capacitances will be negative).  Therefore, Cnn and C_pin would not be
equivalent.

The easiest way to obtain the matrix information would be to use a field
solver on the package design and extract the matrices directly.

- Michael Mirmak
  Intel Corp.
  Chair, EIA IBIS Open Forum

-----Original Message-----
From: owner-ibis@server.eda.org [mailto:owner-ibis@server.eda.org] On
Behalf Of Yasser Sabry
Sent: Sunday, April 22, 2007 7:28 AM
To: ibis@server.eda-stds.org
Subject: [IBIS] Question in R, L, & C Matrix

Hi All,
I have a question regarding [Resistance Matrix], [Inductance Matrix] and

[Capacitance Matrix]
Rnn, Lnn and Cnn are equivalent for R_pin, L_pin and C_pin. Right ?
Rnm, Lnm and Cnm are connected in parallel between pin n and pin m.
Right?

-- 

Thank you and Best Regards,
Yasser Sabry

-------------------------------------------
Yasser Mohammed Sabry
Device Modeling Team  
Analog/Mixed Signal - DSM Division
Mentor Graphics Egypt
Tel: (+202) 416 3613
Mob: (+2010) 1834833
Fax: (+202) 418 6945
E-mail: yasser_sabry@mentor.com
-------------------------------------------




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