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TPS63000: TPS63000 feedback capacitor

Jose Chelotti
Prodigy 20 points
Part Number: TPS63000

Hi! I'm designing a power supply for a system. As a DC-DC converter I am using the TPS63000 for a 5.5V output. I have had some problems with the feedback capacitor (Cff) that is recommend to put in parallel with R1. The recommended value for this capacitor is Cff = (2uS) / R1, whereby I get Cff = 1pF approximately. However there seems to be parasitic capacitances that affect the operation of the circuit (sometimes it works and sometimes not). Also when it does not work the integrated seems to emit a very sharp sound and overheating. Will I need to do a tuning of this capacitor? Can someone give me some information about this?

Attached is a portion of the TPS63000 data sheet:

Thank you for your help!

  • 0
    TI__Expert 8420 points
    Did you try this experiment on the EVM or your board?
    Can you share your schematic and layout? (you can send it by private message if you don't want to share it on a public forum)
  • 0 in reply to Sabrina
    Prodigy 20 points
    Thanks for your answer. Yes, I probe the design on a board that I designed. I could hear a whistling sound when I turned on the module. I checked all the values of the computed components and it's fine. I want to point out that the voltage obtained was correct in general. Sometimes it did not work and the mere fact of touching the integrated with the fingers made it sometimes work (that's why I think it's due to parasitic capacitances). How can I send schematic and layout by private ?. Thank you