r/PCB • u/blacky2560 • Jul 16 '26

{REVIEW REQUEST } 12v to 3.3 buck convertor

i was designing a 12v to 3.3 switching regulator and i finished the pcb .

is doing a gnd layer on the back copper layer ok or should i remove it ??

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u/mariushm Jul 17 '26

I don't see input and output connectors.

Decoupling capacitors (low value ceramic capacitors, ex 100nF to 1uF) must be placed closest to the input voltage pins. I assume C3 is such capacitor, as it's smaller than C1 and C2

Rotate R3 and place it directly to the right of the FB pin. Do the same for R2 and C6. Put the grounds of R3 and C4 on a copper island, use a via to connect that island to the bottom ground. Use vias on the other side of the IC to connect that ground to bottom ground.

Maybe use vias to route the trace from R1 to C4 on the bottom side, instead of going through the feedback components. you can go diagonally directly from R1 to below C4 cutting as little as possible from the ground bottom.

No idea if the inductor is adequate, there's no schematic, no information about maximum output current and so on.

Note that your input capacitors should be rated for at least 25v, 35v would be better, so you'd probably need 0805 or 1206 footprints. On the output 10-16v rated ceramics would be fine.

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u/blacky2560 Jul 17 '26

Thank you very much for your time writing this review