[SI-LIST] Re: Regarding IBIS pkg modelling
- From: Amit KUMAR STE <amit.kumar@xxxxxxxxxxxxxx>
- To: "hermann.ruckerbauer@xxxxxxxxxxxxx" <hermann.ruckerbauer@xxxxxxxxxxxxx>, "si-list@xxxxxxxxxxxxx" <si-list@xxxxxxxxxxxxx>
- Date: Fri, 8 Jul 2011 10:52:41 +0200
Hello Hermann ,
" extracting at one frequency does not mean
the harmonics are not there. They are somehow considered, but might be
wrong"
Does this mean that even if we extracting the pkg file say at 533 Mhz it is
considering second and third harmonics(i.e. 1066Mhz and 1599Mhz) of the signal?
Are you sure about this thing? I don't think my tool does that.
Regards
Amit
-----Original Message-----
From: Hermann Ruckerbauer [mailto:hermann.ruckerbauer@xxxxxxxxxxxxx]
Sent: Friday, July 08, 2011 12:29 PM
To: Amit KUMAR STE; si-list@xxxxxxxxxxxxx
Subject: Re: [SI-LIST] Regarding IBIS pkg modelling
Hello Amit,
basically you are right, but extracting at one frequency does not mean
the harmonics are not there. They are somehow considered, but might be
wrong. And the possible error will get bigger the further the freqency
of a harmonic is away from your extraction frequency ..
the smaller the package and the lower the frequency the smaller a
potential error will be. thats the reason why I propose to use such an
extraction only up to 1Gb for small packages (e.g. DDR3-1066)
Hermann
EKH - EyeKnowHow
Hermann Ruckerbauer
www.EyeKnowHow.de
Hermann.Ruckerbauer@xxxxxxxxxxxxx
Veilchenstrasse 1
94554 Moos
Tel.: +49 (0)9938 / 902 083
Mobile: +49 (0)176 / 787 787 77
Fax: +49 (0)3212 / 121 9008
schrieb Amit KUMAR STE:
> Hello Hermann ,
>
> Thanks for your reply.
> My concern is finally in any pkg model we will extract values for only one
> frequency.
> But the signal will always have multiple frequencies(multiples of fundamental
> frequency).
> So extracting values at a single frequency without taking other harmonics
> into account is wrong acc to me.
> Do you agree?
>
> Regards
> Amit
>
> -----Original Message-----
> From: Hermann Ruckerbauer [mailto:hermann.ruckerbauer@xxxxxxxxxxxxx]
> Sent: Friday, July 08, 2011 11:32 AM
> To: Amit KUMAR STE
> Subject: Re: [SI-LIST] Regarding IBIS pkg modelling
>
> Hello Amit,
>
> You mentioned IBIS pgk modelling and ask for coupling. Not sure if you
> refer to X-talk with "coupling", but X-talk is (so far) not included in
> IBIS package modelling (not lumped RLC and also not in .ebd)
>
> if you use any quasi static approach (e.g. Q3D) use the max. frequency
> of your signal (e. g. DDR3-1066 use 533MHz). At this frequency your
> solution is "most" correct. The further your frequency of interest is
> away from this point the bigger the error can be. Always consider the
> size of the package and the speed of your signal. The max. I would do
> with such a solution is entry speed grade of DDR3 (small package, around
> 1Gb/s). For any larger packages and higher speeds I would use your
> second approach (S-Parameters).
>
> S-Parameter considers the frequency up to which you are going to extract
> (or measure) them. Everything above might be "guessing" (extrapolating)
> of the Simulator which can completely wrong.
> Of course it does not help if you generate a model with a quasi static
> approach and convert this one later to S-Parameters ....
>
>
>
> Hermann
>
> EKH - EyeKnowHow
> Hermann Ruckerbauer
> www.EyeKnowHow.de
> Hermann.Ruckerbauer@xxxxxxxxxxxxx
> Veilchenstrasse 1
> 94554 Moos
> Tel.: +49 (0)9938 / 902 083
> Mobile: +49 (0)176 / 787 787 77
> Fax: +49 (0)3212 / 121 9008
>
>
> schrieb Amit KUMAR STE:
>> Hello All ,
>>
>> When we get any package model extracted , it gives us the coupling values at
>> certain frequency.
>> A digital signal always has many harmonics of a fundamental frequency and
>> hence all those frequency components are important.
>> Which frequency is appropriate for package model extraction then?
>>
>> Also if we use s-parameter model , does the simulator tool take into account
>> the s parameter values at multiple frequencies and come up with the
>> appropriate coupling values ?
>>
>>
>> Regards
>> Amit
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