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EMI noise from PTEA415050

Shahab Inamdar
Prodigy 50 points
Other Parts Discussed in Thread: PTEA415050

Hello Tech Support Team.

I have a question about PTEA415050 part which I am currently using in one of our brand new design.

We are using this component to convert the POE (Power over Ethernet) Supply which is 51V into 5V supply.

This 5V supply is then used to generate 1.2V/2.5V/0.67V/0.78V and is used by our device onboard.

It has been observed, that when the brick is enabled by connecting the Pin-2 to Pin-3 of this component, the EMI noise increased considerably and is injected into MDI lines of our PHY which are running nearby.

I wanted to know if this is a known issue with PTEA415050 and if there is any remedy to prevent this EMI noise from speading to the surrounding circuitry.

Is there any application note which describes how to prevent this EMI noise or something along the same lines?

Any help would be much appreciated.

Thanks
Shahab

408 457 7263

  • 0
    TI__Mastermind 38230 points

    Shahab:

    I attached a suggested EMC/EMI noise filter for the input bus.

    The output ripple attenuation ceramic capacitors are optional.

    Tom

     

    PTEA 41XXXXXinput EMI filter.pdf
  • 0 in reply to Tom Guerin
    Prodigy 50 points

    Hi Tom.

    Thanks a lot.

    However let me make sure that I am going in the right direction.

    As mentioned earlier, I have proved in the lab, that the TI part injects EMI noise to other parts of the circuit. so I need to filter this noise going from TI part to other components.

    So adding this filter circuit will prevent the EMI noise from going out from this TI part to other components. Correct?

    Because it seems like this filter circuit is used to prevent the EMI noise affecting the TI part and not the other way round. Just wanted to confirm.


    Thanks

    Shahab

    PS: I did not receive an email after your reply. I have checked the box which says "email me replies to the post"

  • 0 in reply to Shahab Inamdar
    TI__Mastermind 38230 points

    The EMI/EMC filter when using PI filters of ceramic capacitors and low impedance have proven to reduce conducted emissions by 10 -15db from the  emissions source. The PI filter configuration along with common mode input choke should be  located close to  the noise source .

    Tom

  • 0 in reply to Tom Guerin
    Prodigy 50 points

    Thank you Tom.

    I am going to implement this circuit and see if it makes any difference. Appreciate your timely help.

    Shahab