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PCM3168A: ADC Buffer Figure 58 vs. 59

Ben Gebhardt
Prodigy 10 points
Part Number: PCM3168A

Tool/software:

Hello, 

I am working on designing an ADC buffer circuit for this codec, and I cannot for the life of me discern a substantive difference between the two recommended circuits in the data sheet:  fig 58 and 59.

Obviously there are small differences (input impedance, noise performance, BW) but for me nothing that justifies another two opamps.  No mention in the data sheet about the differences either.

Perhaps the wise wizards at TI could shed some light?

  • 0
    TI__Mastermind 34610 points

    Hi Ben,

    The only differences are what you already brought up. You get higher order filtering with the Figure 58 option due to the cascading filters, but there is no critical reason to prefer that over Figure 59. If you don't think it's worth the cost, then you can use Figure 59 no problem.

    Best regards,
    Jeff McPherson