Hi. I have problem simulating this circuit in Multisim:

(LTSpice)



Here is scheme from Multisim:



When I run transient analysis, I got this:



------ Checking SPICE netlist for Design3 - Saturday, September 26, 2015, 10:58:03 AM ------
======= SPICE Netlist check completed, 0 error(s), 0 warning(s) =======
Transient time point calculation did not converge
Simulation canceled



Any idea what's wrong? Thanks in advance

 

Do you need to connect the unused pins of the IC to something?

 

I don't think I need...

 

I tried different models of opamp and I got same error. Here is my version of software:

 

And with previous version I didn't have problems simulating circuits with opamps. I think this problem has something with opamp power supplies, if I remove them, simulation starts without error. But opamp must have power supply to work

 

Maybe your new software version is more picky about unconnected pins? Wouldn't hurt to add the offset null pot and compensation cap as per the datasheet. Convergence problems often need only a trivial adjustment of a circuit parameter to overcome them.

 

Thanks for suggestions, I will firstly install older version in virtual OS to see if I can simulate same circuit.

 

I get same error on Multisim 13.0.1 Power Pro. There is something wrong with this model of op amp in both versions of Multisim I tried.

 

Can you upload Multisim 13 simulation file?

 

Here it is:

https://www.sendspace.com/file/fv6p17

 

Usually convergence issues are caused by shorts (I think?). Try adding small resistors (1 milliohm) in series with the power supplies. If I remember right, Multisim does not like "backwards" power supplies (used for the negative voltage supply).

 

LOL You connect your op amp power supply backwards. Pin 4 is V- and pin 7 is V+

 

@DerStrom8,
I added 1 miliohm resistors in series with opamp power supplies and simulation starts without error. However, output voltage waveform doesn't look as it should. But I think we are close to solution

 

@Jony130,
I made really stupid mistake
Thanks a lot!

 

But why you simply do not use a LTspice? I think that LTspice is the best software for analog circuit simulation.

 

Well I'm not familiar with LTSpice yet but I definitely need to start using it.