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THS4131 -On harmonic distortion and output voltage

Other Parts Discussed in Thread: THS4131, TINA-TI

Hello Team,

I have a customer who has the following question with regards to  harmonic distortion and output voltage for the THS4131.

"   In figures 18 and 22 the 2nd and 3rd harmonic distortion vs output voltage is shown.  Why do these plots stop at 6V differential when the output voltage can be much higher?  What does the distortion look like at higher voltages?  This is a concern for me because we plan to operate this part at either +/- 5V differential output, or +/-10V.  The load will be at least 1 kΩ, at a frequency of between 50 kHz to 500 kHz .  Figure 27 (Output Voltage vs Diff Load Resistance) shows outputs as high as ~ +/-14V with a +/- 15V supply (1k load).  We are trying to figure out what the distortion will look like with a +/- 10V output.  Thanks. "

Do we have any data beyond what we see in fig 18,22 ? 

Thank you for your time.

Kishen

  • Hello Kishen,

    I don't have any additional data for this part. Probably the best option would be to use TINA-TI to run distortion simulations at high voltage swings. The menu options for distortion are "Analysis->Fourier Analysis->Fourier Series" Make sure to give a delay of at least 0.1us in the Sampling start time box. I like to use the 65536 option for number of samples. You can lower the number of harmonics to 3 or 4.

    Distortion will gradually degrade with larger signals until you get close to clipping. At that point HD3 will increase very rapidly.

    As to why the chart ends at 6V, I can't answer that question. This part was released before I was part of TI. I can tell you that most bench signal generators have a maximum of 20dBm (6.3Vpp), so that would be my best guess for the voltage limit on the graphs.

    Regards,
    Loren
  • Hi Loren,

    Thank you for your assistance with this. As per your suggestion the customer was directed towards TI TINA.

    Sincerely,

    Kishen