• State TI Thinks Resolved
  • Locked Locked
  • Replies 4 replies
  • Answers 2 answers
  • Subscribers 64 subscribers
  • Views 415 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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.

TPS54525: output capacitor consult

Lin_Charles
Expert 4260 points
Part Number: TPS54525

Hi team,

   I want to use this device as below, Vin=5V, Vo=3.3V, Io=5A; if I connect 3000uF in the output, will it have any bad impact? Thanks. 

  • 0
    TI__Genius 9550 points

    Hi, I am looking into this question and will give you feedback on Monday.

  • 0
    TI__Genius 15135 points

    Hi, Charles  

    TPS54525 adopts D-CAP2 architecture, it has very fast transient response, don't recommend to add large caps at the output, otherwise, there might be multi-pulse issue at light loading. Usually, (2 ~ 5) * 22uF are enough for output cap.

    Besides, large output caps will cause big inrush current during output startup, you have to enlarge the soft start cap(cap at SS pin) to enlarge soft start time for reducing inrush current. For 3000uF, you have to use bigger than 68nF for SS cap, the soft start time will be longer than ~9.4mSec.  

  • 0 in reply to Zhao Ma
    TI__Expert 4260 points

    Hi Zhao,

      Thank you for your response here. What do you mean by multi-pulse issue at light loading? If we use 68nF for SS cap, will it have any risk? Thanks.

  • 0 in reply to Lin_Charles
    TI__Genius 15135 points

    Hi, Charles

    1. The multi-pulse issue: Due to the output caps is too large, IC have to output several switching pulses continuously to charge output, you can refer the below output waveform. (It is from other DCAP2 part, not TPS54525 waveform)  

     

    2. Except multi-pulse issue, no other risk.

    Suggest to use SS cap=100nF for smaller inrush current.