[IBIS-Users] "Frequency Dependant IBIS Models"

Hi IBIS Experts,

question about so called "Frequency Dependant IBIS Models".

I understand  why are these things happen (if rising +  falling waveforms on V/T are longer than your clock period), but I still don't know what are simulators doing with V/T curves and dV/dt_r and dV/dt_f? 

I have seen some models where are the trailing points, i.e. points when the rising/falling has finished and response has steady state commented out (or deleted), at it is fine. But, I have also seen some models where are the points with no current change before signal even started to rise/fall deleted, so this V/t curves are artificially made to fit in duty-cycle. That means that fly-by-time (propagation of signal from I/O buffer input to I/O buffer output) of an I/O buffer is reduced to almost zero? Is it OK to do something like that? I don't know what are simulator doing with V/t curves, but on that way fly-by information is lost! Is it needed at all?

If one can delete trailing points or points with no current change and present that as an valid model, do we need then V/t curves at all? Then should be only dV/dt_r,f data enough...Right or I am missing something?

I would be thankful for any kind of answer or link where are these things explained.

Best regards / Mit freundlichen Grüßen / S poštovanjem
Radovan Vuletić

Infineon Technologies AG
MP PD PDE
Room 03.911
Balanstraße 73
D-81541 München

Phone:		+49 (0)89 234 20108
Fax:		+49 (0)89 234 27705
Fax (PC):	+49 (0)89 234 955 5305 

E-mail: radovan.vuletic@infineon.com

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