• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 62 subscribers
  • Views 57 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.

Original question:

LM25149-Q1: Design Review

LM25149-Q1: Calculator output capacitor calculation error and need double-check

Matt Qi
Intellectual 2240 points
Part Number: LM25149-Q1
Other Parts Discussed in Thread: LM25149

Hi team,

My customer used our LM25149, and find the output result of our official calculator cannot match with the manual calculation result.

Could you please help double-check it? The calculator's result is 2.2uF, and the manual result is 12uF.

The mission profile is given following:

The manual result is:

The calculator's result is:

Could you please help provide the result and process from your side? 

Thanks a lot!

Best,

Matt.

  • 0
    TI__Guru 50120 points

    Hello Matt,

    The minimum output capacitance is based on the below equation:

    Are you using similar equation in your manual result?

    I plugged it into my manual result and I got the below.

    The nearest value is a 2.2uF capacitor, however this is not the minimum capacitor needed for stability so we don't usually design Cout for only ripple.

    Regards,

    Jimmy