PLL simulation model in AWRDE

Question

Hi,
Below is a question I got from one of our AWR customers. 
"Can we generate the simulation model of a PLL Synthesizer IC from its datasheet and/or the PLL available in Elements/Systems/PLL of MWO ?
Are there simulation models available in MWO for Analog Devices PLL ICs ?"
My understanding is that if the manufacturer provides the SPICE model of a PLL IC it can definitely be used ina  MWO simulation but I doubt if any manufacturer will. In such a case how feasible is it to build a SPICE model of the PLL from the specifications in the datasheet ? Secondly, since a PLL is a control loop wouldn't it be difficult to close the loop in SPICE programming and have the model converge on a solution in a simulation ? Also, will SPICE models of PLL's simulate fast when there are a lot of extra poles and zeroes for the transfer function ? 
Anyhow, can someone kindly tell me what I can inform my customer about the PLL question ? 
Thank you very much

Answer 1

HI Jake,
    The question becomes what are they trying to do with a PLL model in their simulation?  Do they want to include the phase noise out of a PLL into a mixer simulation or amplifier simulation?  
You can do system level simulation of a PLL but that would be specifying each block's system behavior.    You can search for PLL examples in our help to find these VSS examples.    If you could find a spice model, you could simulate that, but PLLs are definitely a transiety type of simulation and they can take a long time to settle out.  So unless you are trying to simualte the settling time of a PLL, I go back to the original questin of what problem the customer is trying to solve?   This would also depend on the vendor providing the model, which it sounds like they do not.   
The most basic level answer is that the Vendor would need to provide the models available for Analog Devices PLL ICs.  
Thanks,
AWR Support