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I'm designing a switching power supply which outputs -24V using this MAX629ESA+ from Maxim. (Figure 3 - page 7).
Is it generally a good/ok idea to put the inductor on the other side of the PCB as I have limited top space. I have sketched a quick layout that looks like this (don't mind the other Designators)

  1. L2 is the inductor
  2. U7 is the MAX629

MAX629 layout with Inductor on bottom side of PCB

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Is it generally a good/ok idea to put the inductor on the other side of the PCB as I have limited top space.

It's not the preferred method but it's fine. I've done it several times with several different switching regulators and never had a problem.

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  • \$\begingroup\$ Perhaps worth mentioning shielded versus unshielded if he does experience problems? \$\endgroup\$
    – winny
    Commented Nov 11, 2022 at 12:29
  • \$\begingroup\$ @winny I'd always try and use shielded inductors to prevent any serious induction to copper traces. This, I believe, applies to either side of the PCB but, maybe you had some other worry? \$\endgroup\$
    – Andy aka
    Commented Nov 11, 2022 at 12:38
  • \$\begingroup\$ Some EMC course some time ago about this specific situation were they talked about tight situations and paying extra for shielded inductors and placing it on bottom side, right under the IC despite guidelines didn’t recommend it. \$\endgroup\$
    – winny
    Commented Nov 11, 2022 at 14:36
  • \$\begingroup\$ @winny interesting. I nearly always place them underneath despite what the data sheet might indicate!! But, you need to know what you are doing and use multiple vias. \$\endgroup\$
    – Andy aka
    Commented Nov 11, 2022 at 15:28
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    \$\begingroup\$ @Andyaka seconded about the vias :) I usually put multiple connecting vias if I need the same polygon in the other layer (e.g Power Polygon from TOP to BTM layer) \$\endgroup\$
    – Michael
    Commented Nov 12, 2022 at 9:11

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