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Original question:

TPA2000D1: Pop and thump sound coming in through speaker when turning the device ON.

TPA2000D1: Pop and thump sound coming in through speaker when turning the device ON.

TapasXplore
Expert 1280 points
Part Number: TPA2000D1
Other Parts Discussed in Thread: TPD1E10B06

Hi,

I am using volume control pot for changing the volume. As shown in the pic below. It has metallic layer below the volume control button. We are planning for EMC/EMI "ESD" test 61000-4-2. During contact discharge test of +/-8KV, it will pick up the surge. Should it be connected to the ground or it should be connected to the TVS diode like TPD1E10B06. 

 

Regards,

Tapas 

  • 0
    TI__Mastermind 20085 points
    Hi Tapas,

    I am not sure about this, so I need to research it and I will be back tomorrow for further information.

    Best Regards
    José Luis Figueroa
    Audio Applications Engineer
  • 0
    TI__Mastermind 20085 points
    Hi Tapas,

    I consulted with an expert your question.
    The use of the TVS diode depends on the requirements, customer application, and purpose of the testing. If your application is going to use TVS diodes, so you need to add them.

    Best Regards
    José Luis Figueroa
    Audio Applications Engineer
  • 0
    Guru 140200 points
    Hi Tapas,

    the usual ESD protection method is not to allow ESD to touch anything inside of a circuit. The best way to accomplish this is to use a metal enclosure which surrounds the whole cuicuit like a Faraday cage. Then you must think about how ESD leaves your product again. As ESD is nearly always looking for a path to earth (soil) it will either use stray capacitance or the cabling for running back to earth. So, using shielded cables which are 360° bonded to the metal enclosure are the best way to handle ESD. Additionally TVS from the input pin and output pin to the metal enclosure (either direcly or via hybrid grounding) are recommended to protect the circuit against ESD "leakage".

    Now compare your product with this ideal solution. When omitting the metal enclosure, a remedy could be to connect the metal of pot to a ground plane of PCB. This ground plane should be solid and free of gaps. It should span over the whole PCB and should have 0V potential. Directly at the input and output should sit a TVS which shunts ESD also to the ground plane. The solid ground planes imitates the metal enclosure then.

    Why is a metal enclosure shielding against ESD at all? Because ESD is a very frequency interference which runs only on a very thin layer on the outside of a metal enclosure. The mechanism is called "skin effect" and it prevents ESD from entering the metal enclosure.

    Kai