I use an AD9625-2.0EBZ evaluation board to test an AD9625 and I use a Virtex 6 to acquire the dates.
I set the clock frequency at 2GHz and I use the configuration 6 lanes, 1 octects/frame.
When I calculate the ENOB with an Input signal at 20 - 30 MHz the value is 9.1 bits, but at higher frequencies (>50MHz) the value is 6 - 7 bits.
The datasheet reports a value of 9.3 bits untill 500MHz.
The SNR that I find is coincident with the value reports on the datasheet, but with high input frequency I have distortion due at the second and third harmonics.
Can it be due at the evaluetion board? I don't think that I mistake to acquire the dates, because at low frequency the value of enob is correct, and when I bypass the ADC configuring tha SPI to obtain a ramp in output I obtain all value.
Can you help me?