[SI-LIST] Re: Calculating Zin for a DSP Clock
- From: Ray Anderson <ray.anderson@xxxxxxxxxx>
- To: "dmarc-noreply@xxxxxxxxxxxxx" <dmarc-noreply@xxxxxxxxxxxxx>, "jesuscastanemnez@xxxxxxxxx" <jesuscastanemnez@xxxxxxxxx>
- Date: Fri, 21 Nov 2014 17:06:35 +0000
Jesus-
Note that the R_pkg, L_pkg and C_pkg parameters contain the min,max and
nominal values for all the nets in the package. The Zin you calculate for a
particular pin (CLK in your query) using the global data will probably yield an
input impedance far from the actual value for that particular pin.
You really need the [Pin] data (which is not provided in the model you
reference) to get anywhere near an accurate value from your calculation.
-Ray Anderson
Xilinx Inc.
-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On
Behalf Of dmarc-noreply@xxxxxxxxxxxxx
Sent: Friday, November 21, 2014 8:43 AM
To: jesuscastanemnez@xxxxxxxxx
Cc: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Re: Calculating Zin for a DSP Clock
Hi Jesus,
As far as IBIS is concerned, you can use the R_pkg, L_pkg, and C_pkg parameters
(at beginning of ibis file) in your calculations if the individual pin
parameters are not available. These are the default values.
Regards,
Mustafa Yousuf
Sent from my iPhone
On Nov 21, 2014, at 2:49 AM, Jesús Castañé <jesuscastanemnez@xxxxxxxxx> wrote:
> Hi Experts,
> I'm trying to calculate the Zin for the CLK in the ADSP21469.
>
> As far as I know I can use the next equation (Sorry for the plain text
> format)
>
> Zin= srqt [L_pin / (C_pin + C_comp ) ]
>
> I have tried to find this parameters in the IBIS model but L_pin and
> C_pin are defined as N/A
>
> L1 CLKIN PDXO01DG NA NA NA
>
> You can find the IBIS model in this link.
> http://www.analog.com/static/imported-files/ibis_models/ad2146x_cspBGA
> _ibs_ver.1.3.txt
>
> Why are these parameters defined as N/A? What am I missing?
>
> Thank you so much for your help. I find this list really interesting.
>
> Regards,
>
> Jesús Castañé
> uk.linkedin.com/in/jesusalbertocastanemartinez/
>
>
> -
>
>
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