Stats

  • Locked Locked
  • Replies 1
  • Subscribers 125
  • Views 8464
  • Members are here 0
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Vco design s parameters

Psyliver

Hello to everyone. I am having a big problem with a vco on cadence. The problem has to do with the way i am importing the s parameters of an inductor which i have simulated in Ads momentum. Whenever i choose the option linear as interpolation in the nport  i see warnings such as "vgd haw exceeded brakdownvoltage" Which is strange. I am running hb and hb noise as it takes less time than pss as the the tstab runs until steady state is reached and not the whole time as pss. The integration method is trap for tstab. When i choose 1 ps as maxstep everything is fine and also when i choose rational as interpolation in the nport everything works without even setting the max step. The inductor was simulated from 0 to 120 GHZ with 0.1 ghz step. I want to understand what is happening 

Parents
  • ShawnLogan

    Dear Psyliver,

    Psyliver said:
    The inductor was simulated from 0 to 120 GHZ with 0.1 ghz step. I want to understand what is happening 

    Simulating with an S parameter model for a component is something Cadence has provided a number of Troubleshooting and Application Notes - mostly as a result of its expert Ms. Tawna Wilsey. THe most recent version of her excellent presentation material regarding troubleshooting S-parameter model simulation is at the Cadence on-line support site at URL:

    7 Habits of Highly Successful S-Parameters, Spectre 21.1

    A video to walk you through the note is available at URL:

    https://support.cadence.com/apex/ArticleAttachmentPortal?id=a1O3w000009y0apEAA&pageName=ArticleContent

    As the document suggests, one of the most common issues leading to simulation failure or unexpected results is the S-parameter model itself. The document notes some common issues found in an S-parameter model that lead to problems (i.e. missing a DC term, insufficient number of frequency points, causality). ViVA now allows you to plot the S-parameter file for your inductor directly and I would recommend you start by doing that to study the model and verify none of the issues detailed in Ms. Wilsey's document are present. I am thinking this is where your problem lies as with some simulation conditions you are getting "reasonable" results.

    Have you studied the S-parameter file that ADS Momentum has generated? Also, Momentum from my recollection assumes the component substrate is infinite (i.e., ignores loss of actual substrate). If that is still the case, is it sufficient to provide an accurate model for a component that is definitely a 3-D structure and impacted by a finite lossy substrate?

    Shawn

Reply
  • ShawnLogan

    Dear Psyliver,

    Psyliver said:
    The inductor was simulated from 0 to 120 GHZ with 0.1 ghz step. I want to understand what is happening 

    Simulating with an S parameter model for a component is something Cadence has provided a number of Troubleshooting and Application Notes - mostly as a result of its expert Ms. Tawna Wilsey. THe most recent version of her excellent presentation material regarding troubleshooting S-parameter model simulation is at the Cadence on-line support site at URL:

    7 Habits of Highly Successful S-Parameters, Spectre 21.1

    A video to walk you through the note is available at URL:

    https://support.cadence.com/apex/ArticleAttachmentPortal?id=a1O3w000009y0apEAA&pageName=ArticleContent

    As the document suggests, one of the most common issues leading to simulation failure or unexpected results is the S-parameter model itself. The document notes some common issues found in an S-parameter model that lead to problems (i.e. missing a DC term, insufficient number of frequency points, causality). ViVA now allows you to plot the S-parameter file for your inductor directly and I would recommend you start by doing that to study the model and verify none of the issues detailed in Ms. Wilsey's document are present. I am thinking this is where your problem lies as with some simulation conditions you are getting "reasonable" results.

    Have you studied the S-parameter file that ADS Momentum has generated? Also, Momentum from my recollection assumes the component substrate is infinite (i.e., ignores loss of actual substrate). If that is still the case, is it sufficient to provide an accurate model for a component that is definitely a 3-D structure and impacted by a finite lossy substrate?

    Shawn

Children
No Data

Community Guidelines

The Cadence Design Communities support Cadence users and technologists interacting to exchange ideas, news, technical information, and best practices to solve problems and get the most from Cadence technology. The community is open to everyone, and to provide the most value, we require participants to follow our Community Guidelines that facilitate a quality exchange of ideas and information. By accessing, contributing, using or downloading any materials from the site, you agree to be bound by the full Community Guidelines.