Re: [IBIS-Users] differential receiver ibis model

Hi Muranyi Arpad,

Thank you very much for your reply.
Is the sweep voltage ranges for differential buffer same as normal 
3-state buffer?(i.e., -VDD to 2*VDD or 0 to VDD). If my suplly voltage 
is 1.8V, then sweep range is -1.8 to 3.6 or its different.
(sweep voltage range is voltage range of the positive and negative 
terminals of the fully differential buffer)

Thanks & Regards
Raghavendra M

Muranyi, Arpad wrote:
> Raghavendra,
>
> The common mode current goes into the normal [Model]'s
> I-V tables, and the differential current goes into the
> series model that is placed between the two [Model]-s.
> You can further separate the clamp currents from the
> PU and PD I-V curves in the [Model] by redoing the
> same measurements in a 3-stated mode.  (But don't
> forget to put the difference of the clamp and driven
> I-V curves into the PU and PD tables, instead of the
> total current to avoid double counting).
>
> I am not aware of a tool that can do all this in
> an automated way.
>
> Arpad
> =======================================================
>
> -----Original Message-----
> From: owner-ibis-users@server.eda.org
> [mailto:owner-ibis-users@server.eda.org] On Behalf Of Raghavendra M
> Sent: Thursday, September 10, 2009 12:17 AM
> To: ibis-users@server.eda.org
> Subject: [IBIS-Users] differential receiver ibis model
>
> Hi,
>
> I have a fully differential receiver in a chip, am trying to make an 
> ibis model for this receiver
> Can you describe the method how to generate an ibis v3 model for the 
> differential receiver
> I read the ibis cookbook and it says that for a differential buffer with
>
> positive and negative inputs,
> one input should be swept keeping the other input constant(negative) and
>
> record the currents into both inputs.
> Now change the constant input to new value and sweep the positive input 
> and record the currents.
> This process should be continued as the negative input is swept in steps
>
> through the  same range  as positive input.
>  From the current recorded we have to separate common mode and 
> differential mode currents.
> But my question is where should we keep this common mode and 
> differential mode currents in the ibis file?
> Actually for receiver, only clamp data should be kept in ibis file, so 
> in [Power clamp] data where should we keep
> common mode current and differential mode current
>
> Should i use series model for my differential receiver?
> Should we place these characteristics in the model series?
> Is there any tool to generate an ibis model for differential receiver 
> directly?
>
> Thanks & Regards
> Raghavendra M
>
>
>   


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