op-amp internal circuitry simulation

[Mehrzud]

 Hi

I am new to Multisim and I want to simulate 3 op-amps internal circuitry (TL071, LM108, LM110).

I used data sheet to of TL071 (http://focus.ti.com/lit/ds/symlink/tl071.pdf) and I draw schematic in Multisim exactly the same. But when I run AC analysis to get the frequecny responce I get wrong results in comparison with datasheet's graphs.

any idea what is  wrong here?

[yyao]

The datasheet only shows you the topology of an opamp. It is provided to you if you were curious about the internals of an opamp. For example, Q7 and Q8 are JFETs and by knowing this, you will know that this opamp will have an input stage with JFET limitations on bias.

This datasheet provides no characteristics about the devices used. You have no idea the parameters of each BJT (HFE, ft, etc). Neither does it give you any information of transistor sizing or layout on silicon which makes all the difference in opamp performance. Hence it is not sufficient to only draw the design, you must know the parameters of each device which makes up the opamp as well to simulate it.