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PCM2706C: Polarity of the output capacitors C9 and C10 in the datasheet vs C14/C15 in the evaluation board.

Robert Beekhuijzen
Prodigy 10 points
Part Number: PCM2706C


Tool/software:

When looking though the datasheet for the PCM2706C and PCM2707C  the + polarity of the capacitors C9 and C10 is towards the VoutR and VoutL
But in the EVM the + polarity of the capacitors C14 and C15 is towards the output jack/speakers.

Why is that difference? and is there some more information on the design choices for the used resistors and capacitors?

Best Regards,

Robert

  • 0
    TI__Mastermind 47945 points

    Hi Robert,

    The best practice would be for the caps to have the positive side facing the device. The DAC will output with a common mode (VCCp/2) and more often than not the DC bias on the other side will still be 0 no matter what you connect or interface with it. 

    However in the EVM this bias ends up being 3.3V / 2 = 1.15V which is low enough that when combined with the AC nature of the signal, the cap isn't exposed to any dangerous amount of reverse voltage for very long. 

    In a final design I would maintain the direction shown in the data sheet.

    Best regards,
    Jeff McPherson