• Skip to main content
  • Skip to search
  • Skip to footer
Cadence Home
  • This search text may be transcribed, used, stored, or accessed by our third-party service providers per our Cookie Policy and Privacy Policy.

  1. Community Forums
  2. Custom IC Design
  3. A stochastic model in Verilog A for Monte Carlo simulat...

Stats

  • Locked Locked
  • Replies 29
  • Subscribers 125
  • Views 33222
  • 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

A stochastic model in Verilog A for Monte Carlo simulation

UUinfini
UUinfini over 11 years ago

 Hello Guys,

I have a problem for Veriglog A in Cadence, I hope you can help me. In fact I need to elaborate a stochastic model by coding in Verilog A executed under Cadence. My aim is to offer a model with which the customers can do the Monte Carlo Analysis. But I used the functions like "$random", "$temperature" etc. to generate a seed for obtaining a parameter which changes each time of simulation. But finally it changes just according to the real time of simulation, but not according to different times of simulation. Do you have any experiences like this? Thank you for you response.

Best regards,

UU

  • Cancel
Parents
  • Andrew Beckett
    Andrew Beckett over 11 years ago

    Not sure what you mean by "it doesn't work". I created a simple circuit containing an instance of source, and then ran a monte carlo analysis:

    include "source.scs"

    I1 (a b c) source
    r1 (a 0) resistor r=1k
    r2 (b 0) resistor r=1k
    r3 (c 0) resistor r=1k

    monte montecarlo numruns=10 variations=mismatch savefamilyplots=yes {
       tran tran stop=10n
    }

    This outputs a lot of stuff, but in particular it says (for each iteration of the monte carlo):

     hello,I'm glad to meet you -3.38873
    hello,I'm glad to meet you -3.38873
    hello,I'm glad to meet you -3.38873
    .hello,I'm glad to meet you -3.38873
    ..hello,I'm glad to meet you -3.38873
    ...hello,I'm glad to meet you -3.38873

    and then later:

         gmin = 1 pS                                           


    hello,I'm glad to meet you 2.42183
    hello,I'm glad to meet you 2.42183
    hello,I'm glad to meet you 2.42183
    .hello,I'm glad to meet you 2.42183
    ..hello,I'm glad to meet you 2.42183

    (you're strobing on each timestep iteration, so because I ran a transient, it strobes multiple times).

    Because I ran with saving family plots, you can see your signal b in the monte carlo (see attached picture).

    Andrew.

    • monte.png
    • View
    • Hide
    • Cancel
    • Vote Up 0 Vote Down
    • Cancel
Reply
  • Andrew Beckett
    Andrew Beckett over 11 years ago

    Not sure what you mean by "it doesn't work". I created a simple circuit containing an instance of source, and then ran a monte carlo analysis:

    include "source.scs"

    I1 (a b c) source
    r1 (a 0) resistor r=1k
    r2 (b 0) resistor r=1k
    r3 (c 0) resistor r=1k

    monte montecarlo numruns=10 variations=mismatch savefamilyplots=yes {
       tran tran stop=10n
    }

    This outputs a lot of stuff, but in particular it says (for each iteration of the monte carlo):

     hello,I'm glad to meet you -3.38873
    hello,I'm glad to meet you -3.38873
    hello,I'm glad to meet you -3.38873
    .hello,I'm glad to meet you -3.38873
    ..hello,I'm glad to meet you -3.38873
    ...hello,I'm glad to meet you -3.38873

    and then later:

         gmin = 1 pS                                           


    hello,I'm glad to meet you 2.42183
    hello,I'm glad to meet you 2.42183
    hello,I'm glad to meet you 2.42183
    .hello,I'm glad to meet you 2.42183
    ..hello,I'm glad to meet you 2.42183

    (you're strobing on each timestep iteration, so because I ran a transient, it strobes multiple times).

    Because I ran with saving family plots, you can see your signal b in the monte carlo (see attached picture).

    Andrew.

    • monte.png
    • View
    • Hide
    • Cancel
    • Vote Up 0 Vote Down
    • Cancel
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.

© 2025 Cadence Design Systems, Inc. All Rights Reserved.

  • Terms of Use
  • Privacy
  • Cookie Policy
  • US Trademarks
  • Do Not Sell or Share My Personal Information