transformer matching circuit equivalent in virtuoso

[nsarimin]

Dear all,

I need some help. I am designing a transformer matching circuit on virtuoso. As per my understanding, we can estimate the value of self inductances, L1 and L2 (first photo) using the transformer electrical model equivalent circuit (second photo).





How can I create the equivalent circuit in virtuoso so I can simulate with my PA? How about the one in the photo as below?




Thanks

 

[BigBoss]

There is no necessity to draw an equivalent circuit for the transformer.Just draw it as is and simulate your PA.

 

[nsarimin]

How about if I want to model the parasitics capacitance for high frequency PA ? Adding capacitors such as third photo is enough?

Thanks

 

[BigBoss]

How about if I want to model the parasitics capacitance for high frequency PA ? Adding capacitors such as third photo is enough?

Thanks

In fact, the true equivalent circuit of a RF transformer is pretty complex and it does not like to that AC Small Signal and Low Frequency equivalent.in order to get a consistent result, the transformer should be simulated within a EM simulator ( if it's planar type) and s-parameters should be obtained and inserted into circuit.That is the best way to get real design results.

 

[nsarimin]

Thanks

Yes I understand the method you have stated.

For now, I am trying to find the closest possible solution to model in virtuoso to speed up the work.

 

[volker@muehlhaus]

I would simulate the transformer as two inductors with coupling factor, where each of the inductors has a "full" RFIC inductor model. This "full" model has series resistance, parasitic capacitance (for self resonance) and shunt path to the substrate. The shunt path is capacitance from oxide layer, then parallel R||C for the substrate itself.



For ADS, I created a tool to extract equivalent circuit models from measured or simulated S-parameters of inductors.
https://muehlhaus.com/products/equivalent-circuit-model-fit-for-rfic-inductors
For transformers, additional manual work would be required to extract primary and secondary coil, and then add the k factor for coupling.

 

[nsarimin]

Ah yes. I see your point. I will try this solution to speed up the circuit simulation.

Thanks