Full idiot test for Multisim 12 pro

[zauberer1]

I have tested some operational amplifier models with simple inverting amplifier scheme.

And AD380, AD507, AD509, AD515, AD517, AD542, AD544, AD545, AD546, AD547,AD548, AD549, AD5539,

AD542, AD644, AD647, AD707, AD708, AD741 ,AD796 have output voltage greater than power supply voltage.

[Tayyab_R]

Hi zauberer1,

In general, spice models for components are made by manufacturer's to accurately depict the operation of the device. The reason you are seeing these results is because the simulation model for these op-amps are 3 pin models meaning the model does not consider the supply voltage as a parameter. The pins are there to allow you to complete the schematic and have the connections for your PCB. For simulation purposes, the only pins which are being considered in these particular op-amps are the two inputs and the output. This is not the case in general for most of the components.

Sorry for the inconvenience.

[johnsold]

zauberer1,

This is also an opportunity to point out that all simulations are approximations to the real behavior.  Some are more complete than others. It is important to understand the limitations of the model with respect to your particular evaluation. If you want to study the behavior under conditions where the device may operate outside its normal range, then you need a very complete and detailed model.

Any time you run a simulation, you should compare the results to what you expect (from experience, common sense, or other analyses). If there are significant differences, then you need to determine whether the problem is the model, the simulation, or your expectations.

Lynn

[OStep]

Zaubere1 and johnsold,

I agree that unless modeled characteristics are explicitly specified, the expectation is that something as basic as rail clipping should be modeled. And it is for the vast majority of our op-amp models.

Unfortunately there are some op-amp models in our database that use highly simplistic models which do not model clipping behavior (the power pins do not affect the model). These models are included primarily for legacy support. We no longer add such models and many of the existing ones are actually obsolete. 

The easiest way to identify these models is by noting the "Model manufacturer/ID" field. If the model contains "IIT", then it is one of these simplified models. Often you will see multiple models available for a component. Select one that does not contain "IIT".