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TPA3118D2: minimizing pop

KANJI SHIBATANI
Mastermind 6205 points
Part Number: TPA3118D2
Other Parts Discussed in Thread: TPA3128D2

Hello

My customer intend to use TPA3118  Or TPA3128 for their new design FY2018.

They want to have your advise or App. note like as :  http://www.tij.co.jp/jp/lit/an/sloa142/sloa142.pdf,

in order to reduce POP by input cap.

They will use differential input,but due to  their front-end circuit is Not ground-center but biased 6V ,

so they are concerned about the POP deu to un-matching leakage current,

Attached is their idea for minimizing pop, one is reduce leakage current, other is add discharge path.

Would you please give us your opinion?

Best Regards

  • 0
    TI__Expert 6985 points
    Hello! Shawn will review this and get back to you on your configuration. Also, what load are you trying to drive? I see that you are trying to choose between the TPA3118 or the TPA3128... I highly recommend the TPA3128 as it is a P2P newer part, that also offers ultra Low Idle Power Dissipation. Thanks, Jeff
  • 0 in reply to Jeff Kohnle
    Mastermind 6205 points

    Dear Jeff san

    Thank you for your reply. I will strongly recommend TPA3128D2 to customer as per your advice.

    Customer intends to use d-amp battery powered speaker BTL 30W @10%. 

    Speaker impedance (PVDD) is not fixed but within 4~8ohm .

    Best Regards

  • 0 in reply to KANJI SHIBATANI
    TI__Mastermind 24835 points
    Hi Shibatani-san,
    I noticed that the DC bias on the output of the front-end circuit is 6V, which possibly introduces pop noise on the output of audio amplifier. May I know what is the front-end circuit in this application? Is it an amplifier? I think any device between DAC/Codec and audio amplifer is not necessary, because sometimes it would introduce unsteady factors.
    In this application, the common voltage on the left end of the capacitors are 6V, so please make sure the front-end has already been enabled and the common voltage is settled down before enabling the audio amplifier.
    About your solution, looks like it helps to decrease the pop noise on the output, I'm not sure, because we don't have this kind of solution previouly actually. It's worth trying. The value of Rg is important, I think you need to do some tunning on this.
    About the pop noise, please refer to these materials in TI website. www.ti.com/.../slea044.pdf www.ti.com/.../sloa108.pdf

    Best regards,
    Shawn Zheng
  • 0 in reply to Shawn Zheng
    Mastermind 6205 points
    Dear Shawn -san,

    Thank you for your advice immediately.
    I will talk with customer, and I will have feedback if there were any additional questions.

    Thank you again
    Best Regards