@kelu124 designed this board to add high-speed analog inputs to the Raspberry Pi:

20Msps+ ADC RaspberryPi extension

We haven’t tapped yet into the full potential of the Raspberry Pi in terms of ADC. Some have shown that the first gen of Raspberry could go to 10Msps [..] My take is that the new Raspberry Pi’s can surely go above. And I want to try it, either with this old CA3306E or with more recent kick-ass ADCs.

The design files are available on GitHub:

kelu124/bomanz