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TPA2016D2: TPA2016D2 Register Corruption with High Input Signal

Scott Gaetjens
Intellectual 270 points

Part Number: TPA2016D2

Tool/software:

Hello,

I'm using the TPA2016D2 in a voice amplifier application.  The signal chain is pretty straightforward.  Microphone -> class AB output from preamplifier -> TPA2016D2 -> two 8 ohm speakers, one on L channel, one on R channel.  I have an ATTiny84A driving the I2C lines to configure the TPA2016D2.  When I initialize the device and read back the data, the data appears to be correct and the device performs as it should.

However, when I present a high input signal to the TPA2016D2, the registers become corrupted.  Here is what I read back:

Here's a screenshot of my schematic:

I probed the HPOUT node with my oscilloscope and measured around 3Vpp for a 1kHz sine wave before the registers changed.  The datasheet for the TPA2016D2 says the maximum input for INR and INL is VDD+0.3V so I shouldn't be anywhere near the maximum.  Any idea what would cause my registers to get rewritten?  Any help would be greatly appreciated.

  • 0
    TI__Guru** 114015 points

    Hi Scott,

    What is the power supply level? Have you inspected the supply rail with the scope during the same event?
    Perhaps the supply dips considerably after the peak causing the device to perform a power-on-reset.

    Best regards,
    -Ivan Salazar
    Applications Engineer

  • 0 in reply to Ivan Salazar
    Intellectual 270 points

    Hi Ivan,

    I don't see the supply dipping when the reset happens, but I do have around 250mVpp of noise on my 5V supply.  When the reset occurs, an extremely unpleasant high frequency ringing starts coming from my speakers and the power supply noise increases dramatically.  Could my power supply be a problem?

  • 0 in reply to Scott Gaetjens
    TI__Guru** 114015 points

    Hi Scott,

    Is there anything else connected at the output other than the speakers?
    Could you try with the speakers disconnected? If the issue doesn't happen with the outputs floating, then it may point to a power supply problem.

    Best regards,
    -Ivan Salazar
    Applications Engineer