Problem with MC3303 OP AMP model.

[ItsMike]

Hello guys,

I'm having problems with the MC3303 op amp model in multisim 10.
For some reason when the op amp saturates, the output goes way above +v rail and crashes the simulation (37kv or so).

Is there any way to fix the output to get the correct voltage ?
Here is the model:

* EWB Version 4 - 3 Terminal Opamp Model
* A= 200000 RI= 1e+006 RO= 75 VSW+= 15.5 VSW-= -15.5
* Vos= 0.002 Ibs= 2e-007 Ios= 3e-008 SR+= 600000
* fu= 1e+006 fp2= 1e+032 CC= 5e-012
    Vos 4 1 DC 0.002V
    Ib1 4 0 2.15e-007A
    Ib2 2 0 1.85e-007A
    G1 0 5 4 2 0.0584804
    G2 0 6 5 0 0.779738
    G3 0 3 6 0 0.779738
    Ri 4 2 1e+006ohm
    R1 5 0 1000ohm
    R2 6 0 75ohm
    R3 3 0 75ohm
    C1 5 0 3.1831e-005 
    C2 6 0 2.12207e-035 
    Cc 5 0 5e-012

I found a pspice model here, though I really don't know how to convert it to multisim format.

Thanks in advance,
Mike.

 

[crutschow]

That's a three-terminal model so there's no connection to the power rails and the open-loop saturation voltage goes to the computational limit of the program.

To eliminate this either use a five-terminal model with power connections or add a negative feedback clamp to the three-terminal circuit.