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TMS320F280037: TMS320F28003x series internal reference generator

Ajeet Tiwari
Prodigy 15 points
Part Number: TMS320F280037

Tool/software:

Dear TI Team,

I am working on TMS320F28003x series MCU for DC/DC converter project. In its datasheet nothing is mentioned about internal reference source (VREFHI pin) voltage tolerance and temperature coefficient also.

But one TI document i found having marked 50 PPM tolerance. But it was for TMS32F28xx. 

Can i consider same, or PPM value it is different for TMS320F28003x series.

Ajeet Tiwari

  • 0
    TI__Intellectual 2120 points

    Hi Ajeet,

    Then Internal reference for MCU is intended to be used for internal Analog blocks (ADC, DAC).

    The internal reference variation is kind of covered in the module parameters. 

    eg: Gain Error for ADC 

     

    in above table due to internal reference variation an aditional 40LSB is concidered on both sides for Gain error of ADC.

    Let me know if you are looking for any other parameter, will try to help.

    BR,

    Nilesh

  • 0 in reply to Nilesh Khanna
    Prodigy 15 points

    Thanks for reply.

    1. What do you mean by additional 40 LSB. Are you subtracting external reference error from internal reference error.

    2. How datasheet concludes 5 LSB for external reference error. Do they want to tell 5LSB error is due to other circuit parameter. 

       I mean if i will calculate, total error in case of external reference = 5LSB + equivalent LSB error for external voltage source?

    3. This gain itself varies with respect to temperature. Any reference document to get gain error w.r.t temperature?

  • 0 in reply to Ajeet Tiwari
    TI__Intellectual 2120 points

    Hi Ajeet,

    Ajeet Tiwari said:
    1. What do you mean by additional 40 LSB. Are you subtracting external reference error from internal reference error.

    That is correct . 

    Ajeet Tiwari said:

    2. How datasheet concludes 5 LSB for external reference error. Do they want to tell 5LSB error is due to other circuit parameter. 

       I mean if i will calculate, total error in case of external reference = 5LSB + equivalent LSB error for external voltage source?

    5 LSB here is assuming no change in external reference voltage, it only accounts for temperature change  and supply changes for MCU.

    Ajeet Tiwari said:
    3. This gain itself varies with respect to temperature. Any reference document to get gain error w.r.t temperature?

    I don't have any document on this. 

    BR,

    Nilesh