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OPA2196: Monte Carlo simulation with Pspice sub-circuit models

Takashi Onawa
Genius 13200 points
Part Number: OPA2196

Hi Team,

My customer would like to do Monte Carlo simulation with our Pspice sub-circuit models using variant of internal parameters like offset voltage and bias current.
Is it possible to do such the simulation on Pspice for TI software? 

I could find one of tutorial video for monte Carle simulation as below but it's for passive components example.

2.5 PSpice for TI: Monte Carlo Histogram and Temperature Sweep Analysis
training.ti.com/.../pspice-ti-monte-carlo-histogram-and-temperature-sweep-analysis

Regards,

Takashi Onawa

  • 0
    TI__Intellectual 1955 points

    Hello Onawa-san, 

    It is possible to emulate this with a little creativity. First you must measure the Vos of the amplifier model. Then, apply an equal and opposite voltage source at one input to cancel it. This gives you an offset voltage of zero. 

    You can make a separate circuit component that acts as a toleranced voltage source (one approach is shown in this article, but there are a few ways to do it), then instantiate it in your circuit.

    You can then adjust the nominal value and tolerance values to mimic the offset distribution (which could require using two such sources in series with opposing setpoints for a zero-centered offset). I imagine Ib could be addressed in a similar fashion.

    Cheers,

    Jon

  • 0 in reply to JMac
    Guru 47535 points

    Hey Jon, I was working with this a bit in TINA. Do you know of a way to generate a histogram from MonteCarlo DC sims in TINA?

  • 0 in reply to Michael Steffes
    TI__Intellectual 1955 points

    Hi Michael,

    Unfortunately I don't have the full version of TINA with the Monte Carlo capability, so I've never done this myself. That said, I found a training document that gives the following instructions for generating histograms after Monte Carlo runs (not sure which version of TINA it was written for). It is in the context of a Monte Carlo sim of a simple 100k/100k resistor divider, after the window with all the stacked curves has appeared. The input voltage of the divider was swept from 4V to 6V for this example.

    The histogram generation process is continued by selecting the graphics plot Edit > Select all curves. The curves change from their various colors in the plot to all red. Less curves could be selected but it is difficult to differentiate and select between them. That is accomplished by simply clicking on the desired curves.

    Next select Process > Statistics. The Tolerance Analysis - Statistics window appears. Select CUT  and enter a voltage in the box. This voltage is the input voltage Vin, the voltage at which the histogram will be associated with.  Don’t confuse the input voltage with the output voltage, even thought the histogram will be generated for the output voltage. A CUT or input voltage of 5V is entered. The histogram is then associated with the spread in the 2.5V output voltage.

    Pressing Calculate in the window adds a lower portion to the window where the Mean, Standard Deviation and Nominal Value are presented. Pressing Draw produces the histogram.

    The histogram shows the output voltage distribution for the 64 cases, associated with the random tolerance values selected by the Monte Carlo analysis.

    Credit for the above goes to TI's own Thomas Kuehl! I believe the "CUT" is basically just the point of interest, although it seems like there are some other options as well so you may need to play around with it to get the output you want.

    Edit: I also found a video that covers this topic here - https://training.ti.com/ti-precision-labs-adcs-using-spice-monte-carlo-tool-statistical-error-analysis 

    Cheers,

    Jon

  • 0 in reply to JMac
    Guru 47535 points

    Hey thanks Jon, I have V11 which generates montecarlo - will give this a try when I get back to Tucson from the Black Hills and Montana. 

  • 0 in reply to JMac
    Guru 47535 points

    Hey Jon, 

    I downloaded that slide deck, by Art Kay? I did see a chinese slide deck on this by Tom Kuehl, is that available in English anywere? 

  • 0 in reply to Michael Steffes
    TI__Intellectual 1955 points

    Hi Michael,

    Please see attached for the English version (hopefully the attachment works) of Tom's presentation.

    TINA training by Tom Kuehl.ppt

    Enjoy your time in the Black Hills and Montana! That part of the country is incredibly gorgeous, the view from Black Elk Peak is especially amazing if you have the chance to climb up there. I also highly recommend the drive through Spearfish Canyon, assuming you haven't already left the area haha.

    Cheers,

    Jon

  • 0 in reply to JMac
    Guru 47535 points

    Thanks Jon, that appears to be the holy grail of TINA training - And thanks for the spearfish idea, heading through that way tomorrow -will try to cruise through.