Hello Raghu,
I support the audio CODEC products so I have a few questions and suggestions. How many channels of ADC do you need? Do you need any DACs?
The AD1974 is the version of the AD1939 family with only four ADCs.
Then there is the ADAU1977 and ADAU1979 which has advanced microphone interfacing features and it is also a 4 channel ADC.
If you need fewer channel then the ADAU1961 is a stereo version with two ADCs and two DACs. They all will go down to a 15 kHz sampling rate.
Thanks,
Dave T