LMR38010: INDUCTOR GND LAYOUT

Hi kwon

Placing Ground under the inductor is more effective for EMI.

When laying copper at the inductor’s bottom, the magnetic field generated by inductors or other high-frequency circuits creates an eddy current at the copper layer. This current weakens the original magnetic lines, resulting to reduce the inductance of the inductor, and increase the loss.  But the impact is small, and can be eliminated if use a shielded inductor, where there are few leaked magnetic induction lines.

The advantage for placing ground under inductor: an electromagnetic shield can block the magnetic field’s downward transmission, to reduce the high-frequency magnetic field’s impact on other components.

 No need to have vias.

Hi Gui.

Thanks for the reply.

Does this mean that gnd copper+gnd via and only gnd copper have the same emi effect?

Best Regards,

Hi kwon

Yes with/without vias have little impact on the emi. But vias can help improve thermal performance if the inductor is hot.

Thanks and Best regards.

Hi Gui.

Thank you for the detailed explanation.

Best Regards