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TPA3255: Input bias level

John Huberts
Prodigy 25 points
Part Number: TPA3255

The only spec I could find regarding the input voltage level is the maximum input voltage swing, peak - peak of 7 volts. What voltage is this swing with respect to? I'm guessing it's 4 volts above ground.

  • 0
    TI__Mastermind 30210 points
    Hi John,

    The there is a DC blocking Capacitor required on the input. so whatever AC signal you are applying to that input should not be larger than 7 volts from the positive peak to the negative peak. The Capacitor will remove any DC component.

    To clarify, lets say that the output before the capacitor is a 7 V peak to peak 1khz sine wave with a DC offset of 6V. this would make the positive peak 9.5V with respect to ground, and the negative peak 2.5V with respect to Ground.
    The peak to peak voltage is 9.5-2.5 = 7V

    After the DC blocking cap, all you get is the 7V pk-pk 1khz sine wave.
  • 0 in reply to Steve-Wilson
    Prodigy 25 points

    Hi Steve,

    This doesn't answer my question. If there is zero AC swing voltage what is the DC bias level of the inputs?

  • 0 in reply to John Huberts
    TI__Mastermind 30210 points
    Hi John,
    I apologize for misunderstanding, I only saw one question.

    The DC value on the device side of the input capacitor, is AVDD/2. That is with respect to ground of course.

    as per the datasheet, AVDD (typical) = 7.75V

    Best regards,
    -Steve