Modeling in Eagle. How to do an op amp???

Thread Starter

rpschultz

Joined Nov 23, 2022
416
I've been learning Eagle, and most recently trying to figure out how to simulate in the Spice section. Been watching Youtube stuff, it's mostly pretty good. I am using a TL072, and I found that in Linear library. But when I go to the ADD MODEL, I can't figure out which Spice Type nor how to map it.

Can someone help me?
Thanks!
 

Papabravo

Joined Feb 24, 2006
21,305
I've been learning Eagle, and most recently trying to figure out how to simulate in the Spice section. Been watching Youtube stuff, it's mostly pretty good. I am using a TL072, and I found that in Linear library. But when I go to the ADD MODEL, I can't figure out which Spice Type nor how to map it.

Can someone help me?
Thanks!
When it comes to circuits like an opamp there are multiple approaches that can be taken. The simplest approach is the behavioral model which can be done with a voltage or a current source. Here is an example of a generic opamp from @Bordodynov's LTspice library

.subckt opamp 1 2 3 Vh=12 Vl=-12 Aol=100K GBW=10Meg Rout=50
.param vv=100m
.param c=Aol/GBW/6.28318530717959
b1 0 4 i=vv*tanh(v(2,1)/VV)*Aol Rpar=1 Cpar={c} ic=0
b2 0 3 i=limit({Vl},v(4),{Vh})/{Rout} Rpar={Rout} cpar=1p ic=0
.ends opamp
The parameters Vh and Vl are the supply voltages, and the behavior is that of a rail-to-rail amplifier.
Aol is the default open loop gain, and GBW is the gain bandwidth product.
Rout is the default output impedance. The hyperbolic tangent function is used to make a smooth transition between the rails specified by Vh and Vl.

Most of the manufacturer's models are somewhere between this simplified behavioral mode and a transistor level model. Making a model that shows actual circuit behavior from a datasheet is difficult and obscure. the people who do make those models have detailed data from their fabrication and testing processes that are not represented in a datasheet.
 

Thread Starter

rpschultz

Joined Nov 23, 2022
416
I’m not in front of my computer, but I found an op amp in The library. I think there was a spice sim folder in the library. Not sure. Look around. I also may have found the specific TL072 model and added it to the op amp in the library. Stuff in the library is probably only symbols, but you can add the model behavior to it. YouTube it.
 
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