I have a problem concerning this Simple Switcher found here. I used the design example 3 for the LMR10510Y found on page 17 of the datasheet, however measuring the output pins of the switcher returns 0V on the Feedback and SW Pin. VIN receives 5V and EN is around 2.0XV. Here is a picture of my schematics and the board layout (I considered the layout considerations found in the datasheet): enter image description here

Any Ideas what went wrong? If the question is too broad please ask!

  • \$\begingroup\$ Is Diode possibly backwards? Do you have a load attached? \$\endgroup\$ – StainlessSteelRat Apr 11 '16 at 15:50
  • \$\begingroup\$ In this schematic it appears that D1 is across pins 1 and 2 of your chip. In this layout it appears that D1 is connected to pin 3 of the chip, and I don't see anything connected to pin 2 of the chip. Something got mirrored or left out or both? \$\endgroup\$ – davidcary Apr 11 '16 at 16:12
  • \$\begingroup\$ @davidcary Yes, you are right. I changed the layout in the mean time and now I measure 0.8V at the out pin. However 3.3V were to expect, do you happen to know what went wrong? \$\endgroup\$ – optional Apr 15 '16 at 13:19

You've used the wrong pin-out for the device. The pin-out you've used is (somehow) partly for the WSON package but you've got a SOT-23 on the PCB: -

enter image description here

On your PCB you have pin 1 connected as if it were the FB pin yet, for a SOT-23 pin 1 is SW etc...

You also don't appear to have GND (pin 2) connected (I've highlighted it in green): -

enter image description here

  • \$\begingroup\$ My hero! You checked his pinout! \$\endgroup\$ – Gregory Kornblum Apr 11 '16 at 16:55
  • \$\begingroup\$ @Andy I changed the layout and now I get an output of 0.8V at my pinout, expected were 3.3V, do you happen to know what went wrong again? \$\endgroup\$ – optional Apr 15 '16 at 13:17
  • \$\begingroup\$ Check the resistor values and the diode placement. \$\endgroup\$ – Andy aka Apr 15 '16 at 13:22
  • \$\begingroup\$ @Andy Alright, will do! Thanks so far ;). I need to work a lot next week, if I won't be able to resolve the problem I will open another discussion. Have a nice weekend! \$\endgroup\$ – optional Apr 16 '16 at 12:08

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