Transient simulation of nport (s-parameter) in spectre cadence

I have s-parameter data exported into Cadence, and used in nport
component. Depending on whether I choose windowing=yes or
windowing=no, or set the maximum frequency limit for the n-port, or
using equivalent y-parameter or z-parameter instead of s-parameter, I
either get error in transient simulation (Signal V(...) = 1.3 GV
exceeds the blowup limit for the quantity `V' which is (1 GV). It is
likely that the circuit is unstable. If you really want signals this
large, set the `blowup' parameter of this quantity to a larger value.)
or get different result which are not consistent with each other.

In some cases, it suns for a while, then complaines about this problem
after that time slot. But, when I look at the waveforms upto that time
point, no voltage is such large.

Of course, the component whose s-parameters I'm using is not passive.

By switching from S-parameters to Z or Y-parameters, the result
changes, and in some cases the result is not reasonable (e.g.
generating other frequencies, which I think should be coming from IFFT
for converting frequency-domain to time-domain).

I'm using linear interpolation. Even by providing the date for a
frequency range much larger than the input frequency, and setting the
"Max frequency of interest" in the properties of the nport compoonent,
and setting "Frequency sampling interval" (in the properties of nport)
equal to the frequency step of the provided s-parameter data, the
result is different from what it should be.

I would appreciate to know your experience on using nport properly in
transient or pss simulation.

Thanks.

 

I have also provided the s-parameters fro a very low-frequency at DC.
Even by increasing the frequency resolution at low-frequencies, this
inconsistency problem still existed.

 

Correction: the component whose s-parameters I'm using IS PASSIVE,
IT'S NOT ACTIVE.

 

Correction: the component whose s-parameters I'm using IS PASSIVE,
IT'S NOT ACTIVE.

 

Did you check the nport application note on sourcelink.cadence.com ?
Search in just the application notes for "nport", and you'll find it:

"Using the nport Component from the analogLib Library Application
Note"

The direct link is:

http://sourcelink.cadence.com/docs/files/Application_Notes/2005/nportAN.pdf

Andrew.