• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Answers 1 answer
  • Subscribers 31 subscribers
  • Views 500 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPA3118D2: Can the output inductor be removed if the output cable is less than 30cm

louie li
Prodigy 170 points
Part Number: TPA3118D2


I'm using TPA3118 to disign an amplifier, which is put near the speaker. Since output inductor can bring ilinar distortion, Can the output inductor and capacitor be removed? will this improve performance of speaker?(I know this may radiate 500khz radio to the air, but the more I care is sound quality.)

Besides, datasheet only shows performance in 400khz, but will the high-frequency performance be better if set freq at 1200khz? (e.x.  will THD at 6khz low down?)

At last, may I ask why thd at 6khz is the highest, even higher than that of 15khz.

Thanks for your patient.

  • 0
    TI__Genius 11080 points
    Louie,

    The distortion comes from two parts: device and inductor. usually device THD is the dominant. you can remove the LC to get a bit better THD.

    Higher frequency usually has better THD.

    The reason 6Khz is highest is: a 20KHz AES17 filter is applied in class D amplifier test, that is a test method specified by AES. for 15KHz, the third harmonic is filtered out, so it looks like 15KHz is good.


    Dylan
  • 0 in reply to Dylan Yao
    TI__Genius 11080 points
    And in fact 15KHz is really good, because 45KHz is in-audible for human ear.
  • 0 in reply to Dylan Yao
    Prodigy 170 points
    Thanks for your perfect answers. Since a higher chip frequency can bring better sound. For example, the code of AM0 AM1 AM2 for 1200khz is 001, datasheet shows that connection to GND means 0, but how to let AM port be 1? can it be connected directly to VCC24V? Or if AM port is idle(connect to neither GND nor VCC),will it also stand for '1'?
    Can you offer related graphs at other freqs? for example those at 1200khz(Datasheet only shows graphs at 400khz)
  • 0 in reply to louie li
    TI__Genius 9995 points
    Hello,

    Please refer to the datasheet by searching "AM"and you will get all these answer.

    Regards,
    Alix Wan.