And once more. Every thing you can find on datasheets. And schematic diagram, how connect crystal (if needs) to the A/D, and frequency range too.

if you have specific analog signal frequency, you should use sample rate twice less. For example, if max. frequency in A signal is 100 kHz
it is enought 50 kHz sample rate. Of course, you can use 100 kHz if your microcntroller is fast enought and it will not be overloaded. f/2 is necesary for wave form reconstruction.
Have this in mind, when you are choosing A/D chip :)

Another thing, you should use filter to remove higher frequencys then your sampling rate, otherwise you will convert noice from upper frequencys :)


enjoy :)