Pin not driven warning, only on some ICs

Please take a look at this picture:

  • Pin 9 of U6 is power output
  • Pin 3 of U1 is power input
  • Pin 4 of U2 is power input
  • Pins of L1 are passive
  1. Why the warning of “pin not driven” is fired on U2 only?

  2. I’m aware I can just add a PWR_FLAG to the +3V3 rail, but it should not required here. I read the tutorial and because I set the output pin of U9 as “power output” the ERC should be fine with this. L1 is passive so the property of the signal should pass-through.

The warning is only once per net.

Nope.

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The ERC has no idea what an inductor/resistor/capacitor is, it cannot know a signal passes through.

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