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DAC8832: Temperature coefficient for internal resister Rfb and Rinv

Michiaki Tanii
Expert 4360 points
Part Number: DAC8832

Hi team,

 

Could you kindly share the temperature coefficient (ppm/C) for internal resister Rfb and Rinv ?

Customer needs it to estimate drift for temperature.

They would much appreciate if you will share the relative temperature coefficient between Rfb and Rin.

 

Thank you and best regards,

Michiaki

  • 0
    TI__Mastermind 18546 points

    Hi Michiaki,

    I need to check this with designer for info. Please hold on..

    Also if I look at datasheet, the matching between these two resistors is given for typical and max values. Max values will be across temperature.

    from that data, customers can get an idea about how much error they can expect from these resistor variations  as well.

    Nevertheless, I will check and reply soon.

    Regards,

    AK

  • 0 in reply to Akhilesh K
    TI__Mastermind 18546 points

    Hi,

    Unfortunately we don't have data for individual resistors temperature coefficient, but their ratio temperature coefficient will be approx. 2ppm (max)

    Hope this helps.

    Regards,

    AK

  • 0 in reply to Akhilesh K
    TI__Expert 4360 points

    Hi AK,

     

    Please let me double check on your answer.

     

    Looking at the datasheet, the ratio of RFB / RINV is typ 1 ohm/ohm.

    You means that the temperature coefficient of RFB / RINV is max 2ppm / C.

     

    Is my understanding correct ?

     

    Thank you and best regards,

    Michiaki

  • 0 in reply to Michiaki Tanii
    TI__Mastermind 18546 points

    Hi,

    Ratio drift is 2ppm/C (Max), it has to be ideally zero, since both these resistors in the same die and they experience same temperature and so is the drift.

    So when you take ratio of those resistors, drift will be cancelled out. Individual drift numbers we don't have. For customer bipolar application, ratio is what matters

    Regards,

    AK

  • 0 in reply to Akhilesh K
    TI__Expert 4360 points

    Hi AK,

     

    I understand that the ratio drift is supposed to be zero in ideal case.

    I would like just to confirm that the ratio is RFB/RINV or not.

     

    And the ratio error is determined max ±0.0076 % over temperature.

    If ratio drift of 2ppm / C is used, the ratio error would be 0.01% at Tj max but the value is bigger than the ratio error.

     

    I think we can say that customer can use the ratio error in worst case without ratio drift.

     

    Thank you and best regards,

    Michiaki

  • 0 in reply to Michiaki Tanii
    TI__Mastermind 18546 points

    Hi,

    Yes, you can say that, No problems.

    Regards,

    AK