Transformer model simulate in Spectre pss. PROBLEM

[wccheng]

Dear all,

I am using ADS momentum in Virtuoso to synthesize one transformer. I use this transformer for differential input and single output. I have tried to simulate stand-alone transformer model in spectre pss, dc, sp. It could simulate out.
After I connected this transformer in my circuit and simulated pss, it always said that could not solve the singular matrix and fail the pss simulation. Could anyone teach me how could I solve this?

Thanks,

wccheng

 

[BigBoss]

PSS is a simulator developed essentially for linear/nonlinear circuits and systems and it's not very suitable for standalone passive circuits.
To simulate a passive circuit, you should use s-parameter simulator or AC simulator.
Convergence problems are very variable and depend on circuit topology and netlist, that's why you're gonna find a way to simulate your circuit.

 

[wccheng]

However, I need to use this transformer in my mixer design. So, I need to use PSS + PAC. How could I simulate it?

thanks

 

[BigBoss]

However, I need to use this transformer in my mixer design. So, I need to use PSS + PAC. How could I simulate it?

thanks

OK, of course you should use PSS+PAC but overcome these convergence problems, you should use RLCk equivalent circuit instead of s-parameters because s-parameters can create some discontinuty
convergence problems because of limited frequency samples.I have seen many times this problem and it can only be eliminated by connecting 1fF small capacitors to each node or some trciky methods such as connecting each branch to ground by 1G Ohm resistor etc.Sometimes, these methods wouldn't work..it's not guaranteed.
So, there isn't any determined solution for that , you should try and see...

 

[wccheng]

Thanks for your helping BigBoss. I will try it on monday and tell you this is work or not.

 

[wccheng]

So poor!!! I have tried to add 1G-ohm resistor to ground in each transformer node. The pss is still failed

 

[wccheng]

finally, I found it is caused by the bug of the spectre. After I use another version, the problem is solved.

 

[volker_muehlhaus]

This is interesting - I assume that you used S-parameter files for the transformer model?
Can you post the version of Spectre that finally worked for your model?