MCP6021/2/3/4 Spice Model

Thread Starter

tindel

Joined Sep 16, 2012
681
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?
 

MikeML

Joined Oct 2, 2009
5,444
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?
What do you mean by the "negative input resistors"?
 

Thread Starter

tindel

Joined Sep 16, 2012
681
What do you mean by the "negative input resistors"?
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.
 

Bordodynov

Joined May 20, 2015
2,454
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.
 

Thread Starter

tindel

Joined Sep 16, 2012
681
@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!
 

Bordodynov

Joined May 20, 2015
2,454
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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