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TPS63070: Ripples in input with ferrite bead.

Ram Sai
Prodigy 60 points
Part Number: TPS63070

Hi Team,

I have simulated buck/boost converter circuit with TPS63070RNMR in TINA TI. When I used ferrite bead in the input, I observe ripples in the input waveform (In schematic, VIn:5 node) after ferrite bead for both transient and steady state analysis.

My questions are:

1. Is it suggested to use ferrite bead in input. Because I don’t see any ripples at input supply without ferrite bead.

2. If yes, please suggest me a best way to reduce the ripples after ferrite bead in input to IC.

3. If no, please let me know the disadvantages of not using.

I have attached the simulation results and my schematic for reference.

Thanks in advance.

Regards,

Ram Sai.

  • 0
    TI__Expert 7925 points

    Hi Ram,

    It is public holiday here today. I will look into your circuit on Monday and get back to you. Sorry for the delay.

    Best regards,
    Milos

  • 0 in reply to Milos
    TI__Expert 7925 points

    Hi Ram,

    I am sorry for the delay.

    It is not necessary to use a ferrite bead at input, unless you have certain EMI requirements for your design. But even then, to suppress the noise you should first:

    • Follow the PCB layout guidelines from the TPS63070 datasheet, in order to minimize PCB parasitics. 
    • Place a small high-frequency ceramic capacitor (0402, 100 nF) as close as possible to VIN pins, in order to filter high frequency noise.

    We did not test the device with input filters, as this depend on the specific requirements, and the filter can also interfere with the converter operation. I suggest you to first stick to the above recommendations in order to minimize the noise emission, and if after tests that is not enough, proceed to add input filtering or EMI shielding.

    Best regards,
    Milos   

  • 0
    TI__Expert 7925 points

    Hi Ram,

    We haven't heard back so we assume this answers your question. If not, just post a reply below, or create a new thread if the thread has locked due to time-out.

    Thanks and regards,
    Milos