I met a problem totally different from my old experiences with under 10MHz ADC. I found that the output data of AD9265 will be different in different sampling rate, even the same input source (function generator with high impedance output).
For example, giving a 0.4V input, I got 0.4V in 10Msps, but 0.41 in 100Msps. Is this the feature of AD9265 or ?!
And I found the offset will increase in higher input voltage. ex 0.8V input, 0.8V in 10Msps. but 0.82V in 100MSps.
At first, I doubt the voltage reference may be affected when ADC operates faster in 100MSps. I applies a high-speed OPAMP to drive the voltage reference input. Furthermore, I applied the expensive low-ESR capacitor to stabilize the reference, but all of these are useless.
Had anyone experienced this?! Please give me some advice how to deal with this problem. Thank you.