The basic model is called OALIN, and is a simple linear model based on open loop gain and bandwidth - it does not model slew rate, clipping, offsets.or current limits, but it analyses very quickly.
At the other end of the 'spectrum', major integrated circuit manufacturers release home-grown SPICE models of their devices - these are very comprehensive because they often model input and output stages at 'component' level - they tend to be slow to analyse because of the wealth of fine detail.
The third option is one which makes use of special SpiceAge primitives and value-constrained polynomial descriptions. This approach is unique because it uses features that other simulators do not offer, like limiting values on polynomials to model non-linear current or voltage limiting stages. To make life easier for you, we have automated the process of device modelling by writing ModelMaker - a utility program to generate operational amplifiers directly from data sheet information. The result is a set of models which analyse very quickly and are remarkably accurate.
The circuit we have provided here uses value sweeping on the feedback resistor to show the relationship between gain and bandwidth - the result is a set of bandwidth curves for each value of feedback resistor.
