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Visitor II
January 14, 2025
Question

L6986 - Output voltage problem

  • January 14, 2025
  • 1 reply
  • 393 views

Hello,
I have a problem with the output voltage of 3.3V
With input power up to 6V everything is fine. But when I increase the voltage up to 24V, the output voltage slowly changes from 3,3V to 2,8V. The load is about 50mA
I can't figure out what the problem is, I've tried everything. can you please advise me?schematic.pngTOP.png2.png3.pngBOTTOM.png

1 reply

Peter BENSCH
Technical Moderator
January 15, 2025

Welcome @TomasWayTo, to the community!

Your problem probably has to do with your layout: you have routed the track for feedback directly under the coil L1, so that the track captures the magnetic switching signals from L1 and thus interferes with U1. As the input voltage increases, the duty cycle becomes smaller and smaller (the switching pulse becomes shorter and shorter), which has an influence on the control as a higher-frequency interference.

As a workaround, you can disconnect pin 9 (FB) from the track and replace the connection with a wire that runs around L1 in a wide arc.

Regards
/Peter