OPA847: I set the inverting gain of 2 for opa847 and test the output with TINA.But it seems like the circuit works well ,shouldn't the output oscillates?

opa847inverting2.TSCthere is the .tsc file

kai

thanks for your reply.

Another issue is that when i change the Rf to 140ohm,the osc disappears.It seems unreasonable according to at least 12 of stable gain for the 847.

baolin 

Hi Baolin,

still works for me:

Don't expect too much from all these simulations. Spice models aren't perfect and simulators aren't perfect either. So one should be thankful that TINA-TI does show an oscillation at all, even if you have to use some little tricks and stimuli.

A perfect Spice model would become extremely extremely extremely sophisticated. If you would like to use a perfect Spice model and a perfect Spice simulator you would need a perfect, infinitely fast computer. Things that are not from our real world. So, consider Spice modelling as it is, a nice, awesomely good working tool. No more, no less. Spice modelling is never telling the whole truth 

Kai

When I was writing that datasheet, I added a section on getting any low inverting gain using 2 extra caps, that is in the text of the datasheet - needs to be inverting and essentially shaping the noise gain up to be higher at LG xover. 

kai,

Glad to watch your comments so quickly. And I find the lightly difference between  the two simulations. It's the volt amplitude of the output signal from VG1,which value influences the VF1 output indeed.I don't know if there is any method for choosing the proper value.Maybe it depends on sb's fortune for sb to choose the proper values rightly?

Also,your comments on TINA-TI helps a lot .thanks again.

baolin