Sridhar,
There are thousands of 16 bit ADC's from various manufacturer and the selection depends on various factors.

1. Conversion rate [ samples per second ].
2. Vin i.e. Input voltage Range.
3. Reference voltage [ Internal or External ].
4. Package available.
5. Technology [ CMOS, Biploar, BiCMOS ].
6. Conversion type.
7. Availabilty in local market.
8. Cost.

Please describe your exact application so that these parameters can be fixed depending upon the application.

Regards,
Prahlad Purohit