I am routing a TPS562202S buck regulator, using a 4.7 uH inductor. Due to space and assembly constraints, I cannot place the inductor on the same layer as the regulator. The regulator will be on the top layer, while the inductor will be in the bottom layer. Do you see any disadvantages to this approach? I am attaching a figure of the current layout, where L1 is the inductor, U8 is the buck converter. VEXT is the input power, which passes through a reverse-polarity protection diode and a PTC fuse (D7 and F2, respectively). The 4 vias (marked with green arrow) connecting the regulator to the inductor have 16 mil holes. C15-17 are bypass caps on the input.

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UPDATE: This is how it would look in 3D from the top.

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  • \$\begingroup\$ Big L/IC size ratio ;} \$\endgroup\$ Jun 2 at 21:26
  • \$\begingroup\$ You don't show where the output cap is. Probably the biggest driver to "goodness" on this is to have a short, high conductance, low-inductance path from the ground side of the output cap to the chip's ground. \$\endgroup\$
    – TimWescott
    Jun 2 at 21:47
  • 2
    \$\begingroup\$ Being on the bottom is fine. It can actually be better if done correctly. The goal is to reduce total loop area. When you put the inductor on the opposite side, you have the ability to place it across other components and get a smaller loop. I would figure you'd want to rotate it 180° from where it is now, and keep the output bypass caps close to the chip ground. \$\endgroup\$
    – Aaron
    Jun 2 at 21:49

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