ADS1263EVM-PDK: Differential Input Code Conversion

Hello,

         We tried reading data through ADS1263EVM-PDK, But not getting satisfactory results or somewhere our understanding does not meet.

         We have connected below voltage signals to the ADS1263EVM board.

1. IN2 (REF_P) = 4V
2. IN3 (REF_N) = 1V
3. IN0 (Vin_P) = 3V
4. IN1 (Vin_N) = 2V

Please refer "Hardware_Connections.PNG" image for hardware connection as below.

ADS1263 register configuration is done as below

1. MODE0 = CHOP(disabled)
2. MODE1 = FILTER(Sinc1)
3. MODE2 = BYPASS(disabled), GAIN(1), DR(400)
4. INPUTMUX = MUXP(AIN0), MUXN(AIN1)
5. REFLUX = RMUXP(AIN2), RMUXN(AIN3)

Above are the only bits which are changed, rest all configurations are as default. Please refer below image.

With above-said circuit connections and register configuration and as per our understanding ADS1263 should read the difference between two input signals (Vin_P - Vin_N) as 1V. But we are getting ADC reading as 1.67192V. Please refer below image 

The question here is, we are not able to understand from where 0.67192V is getting added?

All the snapshots of ADCPRO software V2.0 for this configuration are attached for reference as below. 

Any kind of help to resolve the issue is appreciated.

Thank you........:)