By referring the datasheet of ADS8902B, it says Vref Input Range: 2.5-V to 5-V
For the minimum Vref 2.5V, it is understood that the input analog voltage of 2.5V will give the output as FFFFF Hex. so that the LSB is (2.5/220 ) = 2.384μV. So that I give this much smaller voltage to input, does this part will sense, convert and give the answer 00001H? or is there any offset/tolerance or limitations will affect the output? What is the the minimum allowable analog input which is sensible and the conversion get start?
