MCP6021/2/3/4 Spice Model

Discussion in 'General Electronics Chat' started by tindel, Nov 28, 2015.

  1. tindel

    Thread Starter Active Member

    Sep 16, 2012
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  2. tindel

    Thread Starter Active Member

    Sep 16, 2012
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    Well, I got it to work by lowering the negative input resistors by an order of magnitude. It doesn't seem to matter in real life. Maybe the sim thinks the input capacitance is higher than it is in actuality?
     
  3. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    I cant get it do the .dc solution. It is complaining about the size of some internal transistors in the model.
     
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  4. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    What do you mean by the "negative input resistors"?
     
  5. tindel

    Thread Starter Active Member

    Sep 16, 2012
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    Sorry I wasn't very clear... the resistors attached to the inverting input.

    I think it's upset because it should oscillate with the large value resistors... but I'm not seeing that in real life. Hmmm.
     
  6. tindel

    Thread Starter Active Member

    Sep 16, 2012
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    That's what I was seeing too.. thanks for the second set of eyes.
     
  7. Bordodynov

    Active Member

    May 20, 2015
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    You are using LTspice? If so, then I can probably help you. I make modifications to improve the convergence of the models. Load your 'asc' file. Then I'll take care of the problem on Monday. Messages (warning) about the size of the transistors are ignored.
     
  8. tindel

    Thread Starter Active Member

    Sep 16, 2012
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    @Bordodynov - Knock yourself out if you'd like. I ended up using a similar part out of the LT opamp database. Based on the opamp models I've seen in the past, this is a classic case of someone (postdoc maybe?) over analyzing something to the point that it's useless. Gotta love microchip... everything works - kind of... including the chips!
     
  9. Bordodynov

    Active Member

    May 20, 2015
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    Not so simple. I modeled the generator current operational amplifier MOS transistor and the source of the reference voltage. I do it for the laser diode. I made a pulsed laser current control. I was looking for that cheapest operational amplifier. For this indicator, I won an operational amplifier from Microchip. But this amp turned excessive current spikes. Amplifier had no other firm of current emissions (at least in the simulation).
     
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