I'm using AD7609BSTZ with an anti-aliasing filter at the input, but the last digit in the count is varying by +/- 5 counts from the actual Count . Is there  any solution to have a stagnant value as we require high precision?

For example the output counts for +10V = 32767, but it varies between 32762 to 32768.

I'm using shielded cables to feed the voltage at the input of the ADC, Also the last two bits are removed from the 18 bit data since we require only 16 bit data, yet the counts keep varying continuously.

The noise free bits measured currently is around 12.6 , but at least 14 bits is the requirement. Please provide more information regarding the Noise Free Bits and its improvement.

Please help.

Thank you