I used ADS8695 in my DAQ system. After my test, I found a problem: The ADC value is bigger than the set point value.
The test data is below：
Set value ADC value ADC value to calculation
0 0 0
4.183V 215072 4.2V
3.684V 189440 3.7V
3.284V 168960 3.3V
2.485 V 128024 2.5V
The ADC configuration is: Range = 1.25REF.
So according to the result is offest value: dV=16mV. But I think the result is not meet the datasheet. Can you help me to check my design?
1、I check the ADC's ref voltage is OK;
2、The schametic is bellow: