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TINA/Spice/DAC7311: DAC7311 : THD issue

Tseng Roger
Intellectual 500 points
Part Number: DAC7311
Other Parts Discussed in Thread: TINA-TI,

Tool/software: TINA-TI or Spice Models

Hi Sir,

I tried running THD of DAC analysis(example:DAC7311 Parallel TINA-TI Reference Design), but THD performance is not good. What's wrong?

 

  • 0
    Mastermind 9990 points

    Hi Sir 

    The customer main question is why Tina simulation FFT result is different datasheet Figure 22. Power Spectral Density.

    May you pls advise there is setting error or something wrong?

                                                                       Bogey

  • 0 in reply to Chen Bogey8
    TI__Guru 52663 points
    Hi Bogey,

    We will get back to you on Monday.

    Thanks,
    Paul
  • 0 in reply to Paul_Frost
    TI__Genius 14220 points
    Hi Bogey,

    Thank you for your query. Did you just run the reference design directly in Fourier Analysis mode or did you input a sinewave pattern?

    The TINA reference design by default doesn't have a sine wave pattern. Hence, it is supposed to have high THD.

    Nevertheless, the THD of a DAC mainly depends on the update rate vs output signal frequency, linearity and code-to-code glitch. While the TINA model might be fairly capturing the linearity, it is very difficult to accurately model code-to-code glitch. That's the main reason, a TINA or SPICE model is not an appropriate tool to evaluate the THD performance of a DAC. We would recommend that you should evaluate the performance based on actual hardware such as an EVM.

    The TINA model mainly captures DC errors, temperature drift, noise, and settling time.

    Hope that answers your question.

    Regards,
    Uttam Sahu
    Applications Engineer, Precision DACs