• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 64 subscribers
  • Views 373 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

LMR14030: lmr14030 low frequency noise issue

Mason Liu
Expert 4035 points
Part Number: LMR14030

Hi,

Recently I built a BUCK(from 24v to 12v) using LMR14030 with the schematic as below, but it doesn’t work well. We observe some very low freq noise in Vin, could you give us some suggestions?

Thanks.

BR

Mason

  • 0
    TI__Expert 8130 points

    Hello Mason,

    Input ripple can be reduced by either boosting the capacitance or reducing the ESR of Cin. I noticed a ceramic cap is used at Cin, which typically has a very low ESR and add little to the input voltage ripple.

    I would recommend to increase Cin. Have you tried increasing the input capacitance?

    Also, let's make sure we are measuring it properly. Improper measurement techniques can result in exaggerated noise. How are you probing the scope-probes? Clip-on method? Please take a look at the following:

    Thanks,
    Alejandro

  • 0 in reply to iAlejandro
    TI__Expert 4035 points

    Hi Alejandro,

    Actually this test is based on our EVM, could you give us the EVM layout file?

    Thanks.

    BR

    Mason

  • 0 in reply to Mason Liu
    TI__Expert 8130 points

    Mason,

    I have contacted you offline and provided the EVM Design Files as requested.

    Thanks,
    Alejandro