We use the AD5547 in a DA-system with 5MHz sampling rate and in 4-quadrant configuration. We use very low bias-current amps for I/V conversion but still measure quiet high distortion of about -60 dB for 3. and 5. harmonics after proper reconstruction filter for fundamentals ranging from 20kHz to 600kHz. The distiotion is sourced from the AD5547/ I/V-conversion part of the circuit, not from the following filters. The used amps have very low distorion specified in those ranges. The capacitor C9 shown on the schematic in figure 23 of the datasheet is matched. Amplitudes of fundamentals are around 5Vpp.
What values of distiortion or THD is to be expected at those frequency ranges? The datasheet only shows THD for a 1kHz fundamental.
