Universal OpAmp Models

What are the differences between the multiple Universal OpAmp models included in LTspice?

In the OpAmps sub directory of the LTspice model library, four levels of Universal OpAmp models are provided for use in your simulations. Each level has different features and may be better suited for different use cases. Of course, there are many more possible applications for these models than the ones listed here.

UniversalOpAmp1 – simple linear gain block with a single pole in the gain/phase response. Useful as a nearly ideal gain stage but with realistic rise and fall times.
UniversalOpAmp2 – all the features of level 1 with added slew rate limit, output voltage limit, and output current limit. Useful as a more realistic gain block or as an easy way to limit voltage or current.
UniversalOpAmp3a/3b – all the features of level 2 with an added second pole (3a and 3b) and delay (3b only) in the gain/phase response. Useful for basic small-signal stability or gain/phase analysis.
UniversalOpAmp4 – all the features of level 3 with added input capacitance, output resistance, and virtual ground. Useful for intermediate stability analysis across different loads and feedback networks, or for floating power supply applications such as 4-20mA transmitters.

Input voltage noise and input current noise are included in all levels.

For more information and a complete list of available parameters for each model, please see the example circuit UniversalOpAmp.asc in the examples/Educational folder.