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AM3352: ADC reference voltage accuracy

Steven Liu1
Expert 4390 points
Part Number: AM3352
Other Parts Discussed in Thread: REF3233

Hi Team,

My customer want to use the ADC module of AM3352. They'd like to learn the accuracy of the VDDA_ADC as they want to use this internal voltage as the sampling reference. I checked the data manual, there's no detailed information about the VDDA_ADC's accuracy. Can anyone help to clarify this information? 

Thanks!

  • 0
    TI__Guru**** 393215 points
    Hi,

    VDDA_ADC is a supply voltage. It must be 1.8V +/- 5%, as specified in section 5.5 of the AM335x Datasheet Rev. J.
  • 0 in reply to Biser Gatchev-XID
    TI__Expert 4390 points

    Hi Biser,

    Thanks for your reply!

    I think the 1.8V +/- 5% is the power supply requirement for the VDDA_ADC. The accuracy that customer asked is the accuracy of the reference voltage when taking VDDA_ADC as the reference.

    If an external voltage is provided through VREFP/VREFN, there are some accuracy parameter about the voltage supply such as the device REF3233 , High Accuracy is 0.01%, shown as below.

    When VDDA_ADC, the internal reference is used, what's the high accuracy? For example if REF3233 0.01% is connected to the VDDA_ADC, can the accuracy still be 0.01% considering its also powering the ADC module ? I'm not sure whether the accuracy will be affect or not.

  • 0 in reply to Steven Liu1
    TI__Guru**** 393215 points
    I have asked the factory team to comment. They will respond here.
  • 0 in reply to Biser Gatchev-XID
    TI__Guru 56085 points

    The AM335x ADC does not have an internal reference. The ADC can be configured to use the VDDA_ADC/VSSA_ADC terminals or the VREFP/VREFN terminals as the reference.  So the accuracy of the ADC reference depends on the source connected to these terminals.

     

    Regards,

    Paul