• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 64 subscribers
  • Views 442 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.

WEBENCH® Tools/TPS54821: tps54821

Pradeep N52
Prodigy 190 points
Part Number: TPS54821

Tool/software: WEBENCH® Design Tools

So here is my concern according datasheet of tps54821 it is recomended to put two 47uF capacitors for output ...atteched screenshot for reference now why can't i use one 100 uF capacitor instead of two 47uF capacitors how this will plays role ....I am new to this design i am not understanding the use of two capacitors instead o f one it may save a footprint

  • 0
    TI__Expert 4720 points
    Hi,
    47uF ceramic cap is more easy to obtain. If you have one 100uF ceramic cap, it's fine to use.
  • 0 in reply to Neal Zhang
    Prodigy 190 points
    As i am working on the above regulator but output is 5V now by using the 100uF capacitor there is drop spike observed when load current increases suddenly ..But if i use two 47 uF capacitor this issue resolved .How it is possible? There should be some reason why this is happening and i didn't understand that
  • 0 in reply to Pradeep N52
    TI__Expert 4720 points
    Hi,
    One possible reason is the capacitance after derating is different. For ceramic cap, if 5V voltage applied on it, the actual capacitance will drop. You can ask your cap manufacture for the data.
    For further analysis, could you please upload Vout waveform when load transient happens, and provide the part number of the cap you use?