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 SP-Simulation : GPC Option 

Last post Fri, Apr 30 2010 3:00 AM by Tawna. 3 replies.
Started by bVenu 28 Apr 2010 11:59 PM. Topic has 3 replies and 2232 views
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  • Wed, Apr 28 2010 11:59 PM

    • bVenu
    • Not Ranked
    • Joined on Thu, Apr 29 2010
    • Posts 6
    • Points 95
    SP-Simulation : GPC Option Reply

    I have a question about how to interpret the power gain circles plotted using Spectre's SP analysis

    For plotting the power gain circles on the Z-smith chart , there are 2 options: Frequency and Gain Level

     Suppose I select sweep  "Gain level"  Start = 5dB , Stop = 20dB , step = 5

    In my circuit, input port = 50-ohms , output port = 500-ohms.

      Will this sweep the value of the output port impedance and create circle with all the points where the power gain is the same?Are the values that we read off the smith chart are output reflection coefficients? Are they normalised to the input port or output port resistance?

     Is there any technote/tutorial that explains how to use the different 'Main-Form" options in the SP analysis?

    Thanks
    Venu

    • Post Points: 20
  • Thu, Apr 29 2010 3:32 AM

    • Tawna
    • Top 25 Contributor
    • Joined on Thu, Jul 10 2008
    • Snohomish, WA
    • Posts 193
    • Points 5,180
    Re: SP-Simulation : GPC Option Reply

     Hi Venu,

     

    Please check out the appendix D of the SpectreRF User guide.  The appendix is called: Plotting Spectre S-parameter Simulation Data

     http://support.cadence.com/wps/mypoc/cos?uri=deeplinkmin:DocumentViewer;src=pubs;q=/spectreRFvol2/spectreRFvol27.1.1/appD.html

     

    You may also want to check out the example:  LNA Design Using SpectreRF AppNote

    http://support.cadence.com/wps/mypoc/cos?uri=deeplinkmin:DocumentViewer;src=wp;q=ApplicationNotes/Custom_IC_Design/LNA_62_appnote.pdf

     

    Best regards,

    Tawna

     

     

     

     

    Best regards, Tawna Wilsey Staff Support AE, Global Customer Support Cadence Design Systems, Inc.
    • Post Points: 20
  • Thu, Apr 29 2010 6:04 AM

    • bVenu
    • Not Ranked
    • Joined on Thu, Apr 29 2010
    • Posts 6
    • Points 95
    Re: SP-Simulation : GPC Option Reply

    Hi Tawna,

    Thanks a ton! Great pointers.

    At the University we have a complete Cadence Installation, could you tell me where I can find the schematic for the differential amplifier described that LNA design spectre RF note (LNA_62_appnote). In case it comes with the installation, there must be some standard path I can search

    It is not present in the rfExample directory @   $CDS/tools/dfII/samples/artist/rfExamples

    rfExamples only has a single ended BJT based LNA circuit.

    best
    Venu

     

    • Post Points: 20
  • Fri, Apr 30 2010 3:00 AM

    • Tawna
    • Top 25 Contributor
    • Joined on Thu, Jul 10 2008
    • Snohomish, WA
    • Posts 193
    • Points 5,180
    Re: SP-Simulation : GPC Option Reply

     Hi Venu,

     

    I recommend looking in the hierarchy at:

    <mmsim>/tools/spectre/examples/SpectreRF_Workshop

    In the directory, there are appNotes there, as well as workshops - one in particular on LNAs.

     

    For more information, please see my blog post from February 2009:
    "Shhhh....SpectreRF Tutorials and Appnotes - One of our best kept secrets!"

     http://www.cadence.com/Community/blogs/rf/archive/2009/02/09/shhhhh-spectrerf-tutorials-and-appnotes-one-of-our-best-kept-secrets.aspx

     

    Good luck and have fun!

     best regards,

    Tawna

    Best regards, Tawna Wilsey Staff Support AE, Global Customer Support Cadence Design Systems, Inc.
    • Post Points: 5
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Started by bVenu at 28 Apr 2010 11:59 PM. Topic has 3 replies.