I'm new in electrical engineering (since I'm a chemical engineer) but I've been working on system dynamics through simulation of a DC circuit that involves Op Amps. One of my main variables to watch is supply voltage. Now, I'm struggling with relating the open-loop gain to supply voltage, especially at low values of the latter. Data handling from simulations of a class of Op Amp (LMC6482) in NI Multisim showed that open-loop gain drops drastically when a certain supply voltage is reached (from high to low voltages) as is expected, but it continues decreasing, reaching almost zero when supply voltage is not zero yet. Is it physically possible to get open-loop gain values that low? Can saturation voltage levels play a part in this situation by decreasing too much while open-loop gain remains at low but not-less-than-unity value? Is there a way of relating other Op Amp parameters to obtain the open loop gain as a function of supply voltage?
If simulation data is not trustworthy at supply voltage lower than recommended operation conditions, what could be the best way to approach to transition between the Op Amp operating from active to passive?