Hi,
Nobody knows your requirements. Neither for hardware nor for software.
* 12 bits resolution ADC --> can be found using comparison charts
* 50 kSps --> depend on your clock frequency, nobody knows...
Also nobody knows:
* whether you want continous sampling, single samples, bulk sampling
* how much sampling jitter is allowed (determines what trigger method you need)
* whether you want to store the data (how many samples)
* or you want to process the data (what algorithm)
* what language you want the code
* what compiler, IDE ...
Klaus