[SI-LIST] Re: IBIS package R,L,C values

  • From: V S <for_si2003@xxxxxxxxx>
  • To: si-list@xxxxxxxxxxxxx
  • Date: Tue, 21 Sep 2004 13:26:48 -0700 (PDT)

Muranyi & Harjeet,

Thanks for correcting me and sorry for causing
confusion. I had misinterpreted the PIN R,L,C with die
parasitics. Thanks for pointing that out.

VS

--- "Muranyi, Arpad" <arpad.muranyi@xxxxxxxxx> wrote:

> Sorry for the unreadable post, I sent it UTF-8
> encoded
> in an attempt to avoid those funny characters, but
> it
> didn't seem to succeed.  Hopefully this one
> (US-ASCII)
> will.
> 
> Arpad
>
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
>
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
> =3D=3D=3D=3D
> -----Original Message-----
> From: Muranyi, Arpad=20
> Sent: Monday, September 20, 2004 11:29 AM
> To: si-list@xxxxxxxxxxxxx
> Subject: RE: [SI-LIST] Re: IBIS package R,L,C values
> 
> I would like to correct a comment below which said
> that the RLC
> values on the [Pin] list will not have priority over
> the RLC
> values listed in [Package].  The best way to do this
> correction
> is to quote the IBIS specification, which says:
> 
>
|=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
>
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
>
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> =3D=3D=3D=3D=3D=3D
> |     Keyword:  [Package]
> |    Required:  Yes
> | Description:  Defines a range of values for the
> default packaging
> |               resistance, inductance, and
> capacitance of the component
> pins.
> |  Sub-Params:  R_pkg, L_pkg, C_pkg
> | Usage Rules:  The typical (typ) column must be
> specified.  If data for
> the
> |               other columns are not available,
> they must be noted with
> "NA".
> | Other Notes:  If RLC parameters are available for
> individual pins,
> they can
> |               be listed in columns 4-6 under
> keyword [Pin].  The
> values
> |               listed in the [Pin] description
> section override the
> default
> |               values defined here.  Use the
> [Package Model] keyword
> for more
> |               complex package descriptions.  If
> defined, the [Package
> Model]
> |               data overrides the values in the
> [Package] keyword.
> |               Regardless, the data listed under
> the [Package] keyword
> must
> |               still contain valid data.
>
|-----------------------------------------------------------------------
> ------=20
> 
> From this it should be clear that the more detailed
> data will
> override the less detailed data if available.  This
> includes the
> RLC in the [Pin] list sections as well as the
> [Package Model].
> 
> The purpose of the [Package] keyword was to provide
> an overall
> description of the entire package. This is why it
> has typ., min.,
> and max. entries.  These values can represent the
> shortest, longest
> and average length lead in the package.  Note that
> the [Pin] list
> section doesn't have typ., min., max. values, it
> only allows one
> values per pin.  This is because the thinking at the
> time this
> was written in the IBIS spec was that the
> manufacturing variations
> of the lead frame are so small that they are
> negligible, and the
> meaning of each individual pin's RLC was to refine
> the overall
> RLC provided in the [Package] keyword.
> 
> The [Package Model] keyword was designed to make a
> more detailed
> lumped and/or distributed description of the package
> available.
> Obviously, this is even better than the lumped RLC
> on the [Pin]
> list, so if available it should be used instead.
> 
> However, even this syntax has serious limitations
> for today's
> high speed simulations, so we developed a new and
> much better,
> general purpose interconnect specification, the ICM
> 1.0.  This
> can be used for connectors, PCB traces, packages,
> i.e. any
> passive interconnect.  I hope some day we will even
> use it for
> modeling the on die passive interconnects with this
> ICM.
> 
> Thanks,
> 
> Arpad Muranyi
> Intel Corporation
>
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
>
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> 
> -----Original Message-----
> From: si-list-bounce@xxxxxxxxxxxxx
> [mailto:si-list-bounce@xxxxxxxxxxxxx]
> On Behalf Of V S
> Sent: Friday, September 17, 2004 8:17 AM
> To: si-list@xxxxxxxxxxxxx
> Subject: [SI-LIST] Re: IBIS package R,L,C values
> 
> Mani,
> 
> Every chip has two parts the package and silicon.
> The
> silicon occupies a small area, let us say, 200 mils
> x
> 200 mils. While the complete package may be 1 inch x
> 1
> inch. There is an interconnect between the silicon
> and
> the package. This package is modeled using package
> R,L,C values. The package interconnect can also be
> modeled as a distributed element using ebd files.
> The
> silicon itself have parasitics, mostly capacitive
> load. Both the Pin R,L,C and the package R,L,C
> values
> are should be taken into account (Most simulators do
> it) when simulating.=20
> 
> 
> In your case the package will not be taken into
> account in case 2. You should see a box outlining
> the
> driver receive when modeling as "ibis device".
> 
> The difference in the two case is usually small -
> especially if the mismatch between the package
> impedance and the board impedance is not
> significant.
> But it will also depend upon the rise time. The
> package impedance must be taken into account if you
> are working on simulation correlation. Usually the
> measurement are done on the motherboard that is
> subtantially far from the actual die ( may be as
> much
> as 1"). In such scenario, the signal at the die is
> substantially different from the signal at the die
> receiver. In such cases, it may be necessary to take
> into account teh package R, L, C values.
> 
> =20
> Some Comments on Harjeet's replies
> 
> The PIN R, L, C values have priority over the
> package R,L,C values.
> 
> - I do not think there is anything like Pin PIN R,
> L,
> C values having priority over the package R,L,C
> values. Both are taken into account.=20
> 
> PS: These R, L, C value are lumped values. For fast
> edge rate these may  not provide accurate results.
> 
> - It it true that these values are lumped valued.
> But
> they are accurate in most cases. The vendors may
> provide the ebd files that have distributed R,L,C
> values rather than the lumped values. I beleive
> that,
> if a vendor thinks that lumped R,L,C values are
> "sufficiently accurate" for the frequency of concern
> ,
> it is ok.
> 
> 
> VS
> 
> 
=== message truncated ===



        
                
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