RE: [IBIS-Users] R_pkg characterization frequency

Michael-

 

Thanks for your comments.

 

Yes, the spec does state that the R sub-parameter associated with the
[Pin Numbers] keyword is a has a DC per-unit-length value for describing
package stubs, however I don't interpret this to pertain to any of the
other R definitions (the package global R_pkg parameter or the R values
in the [Resistance Matrix section].

 

Since current (non ICM) package models in IBIS do not explicitly support
frequency dependent effects one needs to determine at which frequency it
makes sense to extract (or measure) the package parasitic values. We
have chosen to extract the RLC matrix values in our package models at
500 MHz for various reasons. It seems to me that to be self consistent,
the min/nom/max values for R_pkg, L_pkg, and C_pkg defined in the
[Package] section should coincide with the min/nom/max values for R, L
and C defined in the [Package Model] section. Having a high frequency
valued parameter in the model definition and a DC valued parameter in
the global [Package] definition seems like an invitation to confusion
and error.

 

We are currently considering the ICM models as a possibility for the
future. One question that I have is when will the use of ICM style
models become commonplace and which (if any) simulators currently
support ICM models (or have ICM support on their roadmaps).

 

 

Raymond Anderson

Senior Signal Integrity Staff Engineer

Product Technology Department

Advanced Package R&D

Xilinx Inc.

 

 

________________________________

From: Mirmak, Michael [mailto:michael.mirmak@intel.com] 
Sent: Thursday, September 29, 2005 8:12 AM
To: ray.anderson; ibis-users@eda.org
Subject: RE: [IBIS-Users] R_pkg characterization frequency

 

Ray,

 

Thanks for writing.  No statement is made in the IBIS specification
about frequency in relation to losses for RLC data in [Pin] or
[Package].  However, the specification does state that the R term for
[Package Model] is DC only.  

 

Because the original IBIS package model definitions do not explicitly
support frequency-dependent effects, ICM may be a better option for you
to model these losses in packages.  ICM-IBIS integration is being
explored through the IBIS Futures Task Group now, as ICM models and
support for them become more widespread.

 

I hope this helps!

 

- Michael Mirmak
  Intel Corp.
  Chair, EIA IBIS Open Forum
  http://www.eigroup.org/ibis/
  http://www.eda.org/ibis/

 

________________________________

From: owner-ibis-users@eda.org [mailto:owner-ibis-users@eda.org] On
Behalf Of Ray Anderson
Sent: Wednesday, September 28, 2005 8:06 AM
To: ibis-users@eda.org
Cc: Ray Anderson
Subject: [IBIS-Users] R_pkg characterization frequency

 

In checking the IBIS spec I find that the comments given for the
[Package] keyword parameter R_pkg are non-specific when it comes to
characterization frequency. Is R_pkg normally specified as a DC value or
as a high frequency value?

 

When we generate our .pkg file format package models we specify that the
R value given is calculated at 500 MHz. Is it appropriate to utilize
these 500  MHz  R values to determine the min/nom/max values given for
R_pkg ?

 

-Ray

 

 

Raymond Anderson

Senior Signal Integrity Staff Engineer

Product Technology Department

Advanced Package R&D

Xilinx Inc.

 

 



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