I normally just use linear regulators in my designs and this is why...

Switching Regulator in question: https://www.diodes.com/assets/Datasheets/AP65211A.pdf

Circuit: enter image description here Board Layout: enter image description here

The problem I am having is under a 10K load the output is ~10V and is quite noisy(Sorry I will post scope images later if we can't solve this without it, and with a 47-ohm load it drops to 0.8V. I don't see what I could have done wrong. I have removed all other parts from the board except the regulator components.

DK part #s for all the parts used:

  • C6: 732-7526-1-ND
  • C7: 732-7494-1-ND
  • C8: 732-7539-1-ND
  • L1: 587-3143-1-ND
  • C9: 732-7539-1-ND
  • C10: 732-7511-1-ND

  • R2: RMCF0402JT100KCT-ND

  • R3: RMCF0402JT75K0CT-ND
  • R4: RC0402FR-0778K7L
  • R5: YAG2984CT-ND

Right now I am thinking its C8 needs to be bigger, or I have selected a very bad inductor?

Thanks, Kyle


1 Answer 1


I don't know if I should delete this one out of shame, or leave it here for anyone else to learn from...

I didn't actually ground the GND rail on that sub-sheet... So it was left floating, after running a jumper it was all good.

Larger input and output caps are also needed uF instead of nF


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