AD9645 : usage of S-Parameter file

1. Please refer to High-Speed ADC Input Impedance: A Measured Versus A Mathematical Approach | Electronic Design

2. Use the parallel impedance model

Hello UmeshJ,

Thank you for your prompt reply.
I read the article which you mentioned and I understood, I think.
I think the "AD9645_S-Parameter.xls" file is a solution for mathematical approach.

Our customer wants to us to explain how to use the "AD9645_S-Parameter.xls"
So I'd like to know the input parameter of "AD9645_S-Parameter.xls".
I marked two parameter in the attached figure file.



I think these two parameters are should be set by user.
I think the "40" means resistance and "3.50E-12" means capacitance.
But I could not confirm where should I refer about these parameter.

1. What parameter should input to "40"'s cell ? Does this resistance mean the external input resister to dump return spike ?

2. This "3.5E-12", Is this a value referenced  input differential capacitance(3.5pF) in the datasheet ?

Best regards,

y_suzuki

Series means each VIN+ or VIN- pin will have R and jX components in series to GND. 

Parallel means the R and C will appear across VIN+/VIN- pins. this is more straightforward and is listed in the datasheet.

Hello UmeshJ,

It seems that I misunderstood about this two parameters.
The two parameters would been fixed rather than variable.

Thank you,

y_suzuki

yes. they are fixed.

yes. they are fixed.