Hi all,
I need your help to understand how to reach the THD performances reported in OPA690 datasheet. Below the application circuit:
The input signal is 1Vpp, sinewave, 1kHz; the spectrum analyser input impedance is 50ohm. I get this bad FFT:
So basically the 2nd and 3rd harmonic are just 84 and 77 dB far from fundamental, while according to OPA690 datasheet I should get at least 100dB, at this amplitude, frequency and load.