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TPA2011D1: Pop-Noise

GARETH OU
Mastermind 9365 points
Part Number: TPA2011D1

Hi

The customer found that when the TPA2011D1YFF has power, the EN pin On/Off will have a pop sound, causing Pop-Noise, The same situation can also be seen on the TPA2011D1YFFT EVM Board, TPA2011D1YFFT gives 5V Power in, OUT+/OUT- connect to SPK, RCA plug is inserted, no need to input signal, press S1 switch on EVM Board, you will also hear pop sound May I ask what is causing this?? How to avoid this Pop-Noise??

  • 0
    TI__Guru* 98535 points

    Hi Gareth,

    As you may know, there are several threads within e2e regarding pop noise, and many of these about TPA2011D1 specifically.
    Pop noise is mostly caused by mismatches between the input +/- pair. A possible way to analyze and fix it would be to use a scope to check the transient during power up, then add/reduce resistance and capacitance in the signal path to affect the transient. However it may be different when you change from EVM to a custom board, so ideally you should apply fixes on the final hardware.

    Best regards,
    -Ivan Salazar
    Applications Engineer

  • 0 in reply to Ivan Salazar
    Mastermind 9365 points

    Hi Ivan

    The customer has the following 2 TPA2011D1YFFT questions As mentioned in the TPA2011D1YFFT Spec, the Amp input capacitance can use the following formula: fc=1/2πRC 1. Does fc refer to the turning point of the High Pass filter?? Does it mean that the audio source below Fc (including noise) will be filtered? Or does it mean something else?? 2. If it is used for general audio input, is there a recommended fc capacitance value?? or a recommended fc frequency??

  • 0 in reply to GARETH OU
    TI__Guru* 98535 points

    Hi Gareth,

    I'll add comments on each question below:

    1. Fc is the -3dB corner of the high-pass filter. Yes the signals below that frequency will be filtered out.
    2. Customer can design the input filter based on their application requirements, for audio purposes you may want Fc to be as low and close to 20Hz as possible, but there is a tradeoff as the capacitor to do that would be bigger.

    Best regards,
    -Ivan Salazar
    Applications Engineer