Hi Team,
Our customer simulated the OPA4991 sinewave generator circuit and noticed some glitches in the waveform. The supply voltage are +/-5V. Please see the schematic diagram and waveform below for reference. What could be the caused of the glitch in the output?
Danilo
Hi Ashley,
Please see the response of our customer.
Thank you for your complete reply. I know that the unbuffered version may have more distortion. But I still don't understand the glitches. In my simulation I see a lot of glitches that are amplified in each stage .... And this is not something that fit into the distortion definition.
What do you think? Do you think those glitches are generated because of the distortion? Or something else like the slew rate etc...
In addition to my previous message, i have simulated the circuit you proposed and i have even more glitches:
Regards,
Danilo
Hi Danilo,
these are very typical simulation artefacts due to an unsuited time grid during the transient analysis. Even TINA-TI is showing them from time to time:
Keep in mind that the most TI's OPAmp SPICE models are optimized for TINA-TI. You may run into issues when using another simulator like LTSpice for instance.
By the way, these simple phase shift oscillators are not very stable and cannot be recommended in general. I would always use a Wien bridge sine wave oscillator instead, like this for instance:
Or see this very nice circuit from Ron:
And see this link from the awesome Mr. Rod Elliott:
https://sound-au.com/articles/sinewave.htm
Kai
