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    INL/DNL Measurement from Cadence Spectre/Virtuoso Output

    Hello,

    I want to measure the INL/DNL of an ADC designed in Cadence Spectre/Virtuoso.

    I understand the methodology: apply an ideal DAC at the output, apply a ramp signal, or a sine wave and get the output and generate a histogram of the output codes.

    My question is: how to I generate a histogram of the output codes - that is - a plot of the code vs. the code density (how many times the code appears) in Cadence Spectre/Virtuoso ? Won't it just generate the output What should I make the output look like in Cadence Spectre/Virtuoso - what format - in order to post-process in MATLAB and get the histogram of the output codes ?

    Can I use a Verilog-A block in ahdlLib ? Or is their another method ?

    Does anyone have a tutorial, reference, paper or thesis that describes this methodology in Cadence Spectre/Virtuoso ?

    Thank you.

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    Re: INL/DNL Measurement from Cadence Spectre/Virtuoso Output

    Quote Originally Posted by Puppet123 View Post
    I understand the methodology: apply an ideal DAC at the output,
    Ideal DAC is not required.

    Quote Originally Posted by Puppet123 View Post
    My question is: how to I generate a histogram of the output codes
    - that is - a plot of the code vs. the code density (how many times the code appears)
    in Cadence Spectre/Virtuoso ?
    Both Verilog-A and MATLAB are not required.

    Simply do postprocessing of PSF data from Cadence Spectre by Cadence Skill language with Cadence ViVA.

    See https://www.edaboard.com/showthread.php?216697



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    Re: INL/DNL Measurement from Cadence Spectre/Virtuoso Output

    Hello,

    Thank you - can you re-post the hard copy of your setting of "ADE>Tools>Monte Carlo"? They have been removed from the original post.

    So, basically, the procedure is:

    1. Run a Monte Carlo analysis of the output of the ADC. This way you get a histogram of the code outputs and how often they appear.
    2. Post Process the data directly using your Skill Code.

    In the newer versions of Cadence Spectre/Virtuoso, there is a histogram function - is that useful ?

    Once I get this histogram, how do I measure the DNL/INL ?

    Thank you.



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    Re: INL/DNL Measurement from Cadence Spectre/Virtuoso Output

    INL and static DNL are evaluated by ramp signal drive.
    Dynamic DNL is evaluated by histogram for sinusoidal drive.

    Before EDA Tool Play, learn how to evaluate ADC by using actual instruments.

    See https://www.edaboard.com/showthread.php?324289#2
    Last edited by pancho_hideboo; 7th September 2019 at 17:17.



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    Re: INL/DNL Measurement from Cadence Spectre/Virtuoso Output

    Thank you.

    So, I use ramp or sine wave drive to determine my output and then use your script to turn it into a histogram in Cadence/Virtuoso?

    Then I post-process that histogram plot ?

    I think Cadence can generate a histogram plot now, but my question is how to create a plot of codes versus the number of occurrences of that code - in Cadence Spectre/Virtuoso ?

    I would use test equipment to do Data Converter measurements but I dont have access to them now, I just have access to EDA tools.

    Thank you.



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    Re: INL/DNL Measurement from Cadence Spectre/Virtuoso Output

    Histogram is not required for INL and static DNL.

    Surely learn INL and DNL before EDA Tool Play.

    https://designers-guide.org/Forum/At...s/hoge_001.jpg

    https://designers-guide.org/forum/Ya...num=1563670717
    https://www.edaboard.com/showthread.php?385613
    If you truely have MATLAB code for evaluation of INL and DNL, do same thing by Skill language.

    However I don’t think you have such code.
    I think you can not understand INL and DNL at all.
    That’s all.
    Last edited by pancho_hideboo; 8th September 2019 at 02:08.



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    Re: INL/DNL Measurement from Cadence Spectre/Virtuoso Output

    Hello,

    Your answer is nonsense.

    In the future, please answer the question being asked.

    That's all.

    Thank you.



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    Re: INL/DNL Measurement from Cadence Spectre/Virtuoso Output

    Quote Originally Posted by Puppet123 View Post
    In the future, please answer the question being asked.
    First of all, you have to learn INL and DNL before EDA Tool Play.
    That's all.



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