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TMS320F28035-EP: TMS320F28035MPNTEP Internal ADC Reference Accuracy and Tolerance

Asha C
Intellectual 475 points

Part Number: TMS320F28035-EP

Tool/software:

Hello,

We are using TMS320F28035MPNTEP controller in our design.

Could you please provide the accuracy , tolerance level and range of Internal ADC Reference. As per the below table , Internal reference is 3.3V , is it the same as VDDA supply we connect?

Or is it generated internally from VDDA?

 

  • 0
    TI__Mastermind 26420 points

    Hello,

    The expert on this topic is currently out of office until Tuesday 9/3, so please expect a delayed response. I apologize for any inconvenience.

    Best Regards,
    Delaney

  • 0 in reply to Delaney Woodward
    TI__Mastermind 36526 points

    Hi,

    Asha C said:

    Could you please provide the accuracy , tolerance level and range of Internal ADC Reference. As per the below table , Internal reference is 3.3V , is it the same as VDDA supply we connect?

    Or is it generated internally from VDDA?

    It is generated internally from VDDA.

    As for accuracy, we do not specify the accuracy of the internal reference itself. Instead we specify the accuracy of the ADC conversions when using the internal reference. These data points (gain, temp drift) are included in your screenshot. 

    All ADC specifications where the internal reference is not mentioned, offset for example, can be assumed to also apply to internal reference. 

    This of course only applies if you meet other datasheet specifications, such as VDDA requirements.

    Best Regards,

    Ben Collier

  • 0
    Intellectual 475 points

    Hello Benjamin,

    Thanks for the response.

    1. If ADC Internal reference depends on VDDA , as per VDDA Voltage requirement it varies from 2.97V to 3.63V . So if applied VDDA is 2.97V then would ADC Internal reference be 2.97V?

    2. Also , if we are using external reference we connect VREFHI with the external ref voltage and REFLO with GND. 

    Can we switch to internal reference even when VREFHI is connected to external reference using internal registers?

    Please provide the feedback on this!

  • 0 in reply to Asha C
    TI__Mastermind 36526 points

    Hi,

    Asha C said:
    1. If ADC Internal reference depends on VDDA , as per VDDA Voltage requirement it varies from 2.97V to 3.63V . So if applied VDDA is 2.97V then would ADC Internal reference be 2.97V?

    No, this will not be the case, there is regulation for the internal reference. 

    Asha C said:

    2. Also , if we are using external reference we connect VREFHI with the external ref voltage and REFLO with GND. 

    Can we switch to internal reference even when VREFHI is connected to external reference using internal registers?

    Please provide the feedback on this!

    Yes, this should be possible.

    Best Regards,

    Ben Collier