/diy/ - Do It Yourself

Anyone with experience with op-amps in multsim?

The circuit establishes VREF=1.65V at the inverting input, and by using 0 and 3.3 as the non-inverting input, it successfully goes between -rail and +rail, respectively (the gain is rather arbitrary, I'm just adding it for stability).

My problem is then I want to leave the input floating, and have the output 0V, or as close as possible (+/-1 would probably work, so I could lower the gain resistors to 20x or so). I added a 100kohm resistor between the inputs (which should tie them to the same voltage, albeit with a high cross-resistance)

The issue is multisim has a convergence error, and doesn't know how to resolve it. My max timestep is 2e-10, so it's not like it should be a rate error. If I don't have the 100k everything is fine, if I add it the circuit fails to converge.