TMS320F28377D: ADC sampling accuracy

Part Number: TMS320F28377D

Hi team,

My customer is using F28377D(176pin) in AC drive application.

Now they are using F28377D's internal ADC to measure same signal. But testing results are different from different DSP ADC input end.

1. When they use 44pin_ADCIN14, error will be 3LSB
2. When they use 60pin_ADCIND4, error will be 8LSB.

Why do the testing results have different accuracy. I see ADCIN14 pin will connect with all the DSP's internal 4x ADC. But ADCIND4 will only go into ADC-D.