• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 392 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.

LM2775-Q1: Output Capacitance + 8.2.2.5 Note

Kevin Schmidgall
Expert 4000 points
Part Number: LM2775-Q1

Hi,

I have a customer using LM2775-Q1 with output capacitance of 2.2uF, 25V. I wanted to check if that was enough, as a rule of thumb, and ran across a note in 8.2.2.5 that confused me, below:

My question is what is the 2-uF capacitance it recommends in my highlighted seciton? Is that saying to increase the flying capacitor to 2-uF or decrease the output capacitor to 2uF? It isnt clear to me. They have PFM enabled so I wanted to make sure I am interpreting the note correctly.

Regards,

Kevin

  • 0
    TI__Guru* 78440 points
    Hi Kevin,

    It refers to the output capacitor. You need to check the capacitor datasheet or vendor to see what will be the effective capacitance under the 5V output. Ceramic capacitors has voltage coefficient, and the actually capacitor will reduce from the surface value once biased by a voltage.

    Thanks,
    Youhao Xi, BCS Applications Engineering