Other Parts Discussed in Thread: OPA188, TINA-TI, OPA4192, OPA2189, OPA189, OPA4170, OPA4191, OPA191, OPA170
Hi,
I've designed an input signal conditioning circuit using OPA4188 as shown in the figure below:
The input signal is a sine wave with amplitude that ranges from 0 to 14 Vpp and frequency that ranges from 1.5 kHz to 10 kHz.
I simulated the circuit using LTSpice and it performed as expected. However, when I implemented the circuit and tested it, I found that it presents an output distortion, as shown in the figure below:
The figure above shows the results when the input frequency is 10 kHz. However, this distortion is present for frequencies as low as 3 kHz. For lower frequencies the circuit does not present this distortion. I've repeated this test on each of the OPA4188 channels, on different boards and on different OPA4188s. They all presented the same issue.
I've seen similar questions on the forum (like OPA4188: Strange sine distortion and OPA188: TI precision lab EVM OPA188 Output distortion ) but none of them reaches a conclusion.
Did anyone reach a conclusion on these other questions? What could be causing this distortion and how can I avoid it?
Regards,
Filipe