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DAC8565: Total Gain Error

Ryuuichi machida
Guru 12665 points
Part Number: DAC8565

Hello,

Let me confirm about how we should consider total error of gain.

* According to datasheet, there is following description.

1. gain error : +/- 0.2% of FSR (max)

2. gain temperture coefficient : +/- 1 ppm of FSR/degree

And also, I believe that accuracy of internal reference (25 ppm/degree at Type B) will be related to "gain error".

The question is,

Q1. When we concider total error of gain, should we concider only above three elements ?

Q2. If answer of above is yes, could you please tell us how we calculate total gain of error by using above elements ?

Thanks in advance,

 

  • 0
    TI__Genius 14220 points
    Hi Ryuuichi-san,

    Thank you for your query. If you refer to the output equation of DAC8565 on datasheet page 25, the gain of the DAC is given by:

    (VREFH - VREFL)*(DAC GAIN) / 65536

    The DAC gain is nothing but the DAC code. So, any error in DAC gain or the references will effect the gain. When considered across a temperature range, this will also include the drift due to temperature.

    So, we can say that the total gain error is given by:

    (VREFH_Error - VREFL_Error) * (DAC Gain Error)

    where,
    1. VREFH_Error = VREFH Tolerance + (VREFH Drift*Temperature Range)
    2. VREFL_Error = VREFL Tolerance + (VREFL Drift*Temperature Range)
    3. DAC Gain Error = Gain Error + (Gain Error Drift * Temperature Range)

    You can use the following training document for converting different units.

    Hope that answers your question.

    Regards,
    Uttam Sahu
    Applications Engineer, Precision DACs
  • 0 in reply to Uttam Sahu
    Guru 12665 points

    Hello Uttam-san,

    Thank you for your reply.

    >You can use the following training document for converting different units.

    Which document did you point out ? There is no information in previous thread for training document.

    Best Regards,

  • 0 in reply to Ryuuichi machida
    TI__Genius 14220 points
    Hi Ryuuchi-san,

    My mistake. I forgot pasting the link. Please find below:

    e2e.ti.com/.../dac-essentials-how-accurate-is-your-dac

    Regards,
    Uttam
  • 0 in reply to Uttam Sahu
    Guru 12665 points
    Hi Uttam-san,

    Thank you for your reply.
    I will check it and if I have question, I will post on new thread.

    BR,