You will find your ADC from almost any vendor because of the specs you need. It is a very generic ADC. So try and fish for the ADCs in TI, AD or Maxim's website.
Of course, you can undersample an ADC. There will be no problem when you sample it with a slower clock. In fact, the SNR will be improved.
ya...thanks Vamsi Mocherla...i found an ic which is MAX1192.. it omost match wit wat i need except that the sampling rate...how om i going to undersample it? can u show me the method plz...sori for disturbing...