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TPA3128D2: Frequency versus THD+N plots

Akio Ito
Genius 3595 points
Part Number: TPA3128D2

Hi,

A customer requires the Frequency versus THD+N plots of TPA3128D2 on the oscillator frequency 400kHz and 1200Hz.
If TI does not have these, would you measure these datum by following conditions?

PVCC=24V, Gain=26dB, RL=4Ω, BTL, Po=1W / 15W
The cut-off frequency of LC filter and LPF for measurement  should be set  around 50kHz.

Best regards,

Akio Ito

  • 0
    TI__Mastermind 24835 points

    Hi Ito-san,

    Actually the THD performance is the same between 400kHz and 1200kHz. Could you please let me know why customer wants to use 1200MHz switching frequency? With a high PWM switching frequency, the switching loss is also high and then the efficiency is lower on the device. Generally most of our customers use 400kHz, and the performance is good enough in this case.

    Best regards,

    Shawn Zheng

  • 0 in reply to Shawn Zheng
    Genius 3595 points
    Shawn-san,

    Our customer seems to only want to know whether Oscillator frequency influences THD.
    He must have chosen 1200kHz for the reason of the maximum frequency.

    Best regards,

    Akio Ito
  • 0 in reply to Akio Ito
    TI__Mastermind 24835 points

    Hi Ito-san,

    I understand it. Unfortunately we don't have this data(PVCC=24V, Gain=26dB, RL=4Ω, BTL, Po=1W/15W, Fsw=1200kHz) for now. I'm now out of office and on vacation, and I will collect that data as soon as I get back to office. Hopefully I could send you the data on 10/16. Thanks for your patience!

    Best regards,

    Shawn Zheng

  • 0 in reply to Shawn Zheng
    TI__Expert 6985 points
    Hello Ito-san! Is there still an open question here? im not sure if this was solved over email. Thanks, Jeff
  • 0 in reply to Jeff Kohnle
    Genius 3595 points

    Hello, Jeff-san,

    The question whether TI has data our customer wanted to, is closed.
    I promised him to send his required data by October 16. But I do not get the data still now.

    Best regards,

    Akio Ito

  • 0 in reply to Akio Ito
    TI__Mastermind 24835 points

    Hi Ito-san,

    I'm sorry for the late reply, because I'm on the bizz trip. Please find the following charts for the THD performance vs. Frequency with 400kHz and 1200kHz PWM switching frequncy. Test condition is PVCC=24V, Gain=26dB, RL=4Ω, BTL mode.

    Form the above data, we can see that the THD performnce is a little worse with Fsw=1200kHz comaring to 400kHz ar lower frequency, but still in about the same order. We recommend customer to use 400kHz Fsw instead of 1200kHz, for a higher efficiency and a little better performance.

    Best regards,

    Shawn Zheng

  • 0 in reply to Shawn Zheng
    Genius 3595 points
    Shawn-san,

    Thank you very much for your kind cooperation.

    Best regards,

    Akio Ito