TMS320F280025C: what's the input range of the ADC channels, when VDDA is under 3.3V?

Hello Matt,

This is not a recommended operating condition. It is possible that you still get a correct conversion result (technically VREFHI in this case is actually 1.65V so it is still < VDDA). However, when ADC input is > VDDA, it can cause excess current loading on the internal VREF buffer, which may impact performance. Data sheet specifications are not guaranteed if ADCIN > VDDA.

Best regards,
Ibukun

thank you very much.

  TMS320F280049: ADC accuracy, input limits, reference voltage, input range, and more - C2000 microcontrollers forum - C2000︎ microcontrollers - TI E2E support forums

in the above article, i found that: 

 In 3.3V internal VREF mode, the internal voltage reference bandgap is supplying an accurate voltage of 3.3V/2 or 1.65V (which can be measured externally at the VREFHI pin) so VDDA value of 3.3V - 10% would still produce accurate conversions per spec.

if I can ensure the the ADC input pin leakage will not exceed 2uA, then it will be ok when ADCIN > VDDA.  Am I right?