This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPD1E10B09: The audio signal is too low than before applying the part.

Part Number: TPD1E10B09

Dear Ti and all,

For ESD issue, I apply ESD suppress(TPD1E10B09, and ETC). 

But the audio signal is too low than before applying that part.

Below, I attached a circuit file.

Please, review my circuits.

Audio_Devices.pdf

Thank you.

Best Regards,

Inho Jeon

  • Hi Inho,

    Welcome to E2E!

    I see the circuit file contains 19 of the TPD1E10B09.

    What are the device labels of the TPD1E10B09 that are giving you this issue? Is it D11-D14 at the RJ45 connector or are there more devices?

    What is the voltage range on the line these TPD1E10B09 are connected to?

    What is the data speed on this line?

    Best regards,

    Andy Robles

  • Dear Andy,

    The Issue parts is D11,D12,D13,D14,D17,D18, D19,D20. Those are apply for Audio Inputs & outputs.

    I attached about waveform of Audio Input & output for voltage range.

    AUDIO INPUT

    AUDIO OUT

    Thank you.

    Best Regards,

    Inho Jeon   

     

  • Hi Inho,

    In a system the ESD device should essentially be invisible and not affect the data signal. A reason that could be affecting the signal would be the inherent capacitance found in the device. The TPD1E10B09 has a 10pF capacitance that it would essentially add on the line. By looking at the insertion loss graph in the datasheet you may see that this device is more suitable for applications with data speeds of 400MHz and below. What are the data speeds in your application?

    Best regards,

    Andy Robles

  • Dear Andy,

    Thank you for your reply.

    That signals is only audio signals(analog signals).

    So, That signal speed is 20Hz ~ 20Khz.

    I think TPD1E10B09 drop that audio signals.

    So, Review my circuit file, please.
    ex)it is right connected directions parts and etc.....

    Thank you

    Best regards,

    Inho Jeon

    Thank you

    Best regards,

    Inho Jeon  

  • Hi Inho,

    The TPD1E10B09 is a bi-directional device which means that either pin can be connected to the signal line as long as the other pin gets connected to ground. There's no reason for the TPD1E10B09 to be lowering the signals voltage unless for some reason the device is ON, meaning that the voltage differential between PIN 1 and PIN2 exceeds the breakdown voltage of the device. The voltage of the signal lines seem to be +/- 500mV which are well within the working voltage of the TPD1E10B09.

    Is the scope shot you shared, +/- 500mV signal, from the voltage before or after the TPD1E10B09 was applied?

    If the scope shot is the voltage after the TPD1E10B09 was applied, what is the voltage the audio signals should be working on?

    If the scope shot is the actual voltage of the signal lines then the issue is more than likely something else in the system.

    I also noticed you have multiple grounds in the system. Would you also be able to confirm the voltage differential between the audio signal lines and DGND which is the ground that the ESD devices are connected to? Does the voltage differential exceed the breakdown voltage of the TPD1E10B09?

    Bet regards,

    Andy Robles