accuracy of a F/V converter

[01795584233]

Hi,
I am using an F/V converter VFC32KP from TI. The converter is highly linear and the linearity error is 0.01%.At zero frequency the output should be at a max of 4mv according to datasheet. The problem, is it is going upto 16mv, even after trimming with a pot of 100Kohms.Can anyone suggest me on how to get the linearity error reduced?.
It is importanat that I am worried about the linearity is due to the reason that, it is being used in control application in a digital feedback.
Thanks in advance
Senthil

 

[Lewish]

If I read your post correctly, you are taking a digital signal, converting it to analog and then converting it back to digital.
And you are worried about linearity????