I've designed a board, that includes a charging part :

enter image description here

the problem that I have is in the LMS8117A-3.3: enter image description here

here I can measure 5V on Pin1, but nothing on pin2, I was expecting 3.3V : I've check the board and no I don't have any bypass, to test the board, I've put a 3.3V voltage at "target voltage pin" and the board works fine! So my question is how may solve this and what am I missing! This the layout part!

enter image description here

and here a link to the datasheet

  • 1
    \$\begingroup\$ You appear to have the input and output pins on the LMS8117 swapped. Unless the part as shown is on the bottom of the board. \$\endgroup\$
    – JRE
    Commented Dec 4, 2016 at 9:56
  • \$\begingroup\$ Yes, you have possibly connected the 5 V to the GND pin and GND to the input pin. \$\endgroup\$ Commented Dec 4, 2016 at 10:00
  • \$\begingroup\$ @JRE I suppose you should post it as an answer then. \$\endgroup\$ Commented Dec 4, 2016 at 15:40

1 Answer 1


You appear to have swapped the ground and input pins.

enter image description here


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