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TAS5733LEVM: TAS5733L amplifier-supply Capacitor-type, ESR and outgassing

EJ Holleman
Prodigy 160 points
Part Number: TAS5733LEVM
Other Parts Discussed in Thread: TAS5733L

Hi,

I would like to know your thoughts on the choice of amplifier power-supply capacitor for the TAS5733L. Could you please advice?

I made a board that contains among other things the TAS5733L stereo reference design. Supply-voltage is 12V. The amplifier works flawless, I am really happy with it. I copied all BOM-parts and the schematic. The layout is my own, but resembles the reference-design on critical aspects.

However, I would like to encapsulate the pcba in epoxy, to make it like a brick. I am reading horror-stories about outgassing of electrolytic capacitors encapsulated by potting, which is the case for the Panasonic EEEFK1V221P capacitors that buffer the amplifier power supply in the reference design (C1,C2). Could you quantify the potential lifetime-impact in case of operating these 35V-rated capacitors on 12V, encapsulated in potting?

Now the obvious solution, as it seems to me, is to replace C1,C2 by polymer capacitors, such as Panasonic EEHZA1E221V : same capacitance (220uF), lower voltage-rating (25V), ESR way lower (27 mOhm instead of 160mOhm), same case-size 8x8. I do not see any drawbacks other than size and price, however I may be overlooking something. What are your thoughts?

Best regards, EJ

  • 0
    TI__Mastermind 19080 points

    Hi,

    We are connecting to the right team mate to solve this issue. As some team mates are on National holiday in China, reply may be delayed. Thanks for the understanding!

    Regards,

    Hao

  • 0
    TI__Genius 13970 points

    Hello EJ,

    A lower ESR capacitor is actually preferred so that isn't a drawback. However in regards to your question about lifetime-impact of the caps encapsulated in potting that would be a question you should ask the capacitor vendor, we don't have that information.

    Best Regards,

    Luis

  • 0 in reply to Luis Fernandes de Pina
    Prodigy 160 points

    Hi Luis,

    Thanks for your answer.

    Now from practice, I can confirm that the proposed polymer caps are indeed a perfect drop-in replacement.

    When playing music with a beat, there is a clear increase of punch in low and high frequencies, I rather listen to the amp with the polymer caps. 

    At least I think so, but we are entering the subjective audiophiles domain here. :)

    Thanks, all the best,

    EJ