The issue here is that the doc "Hardware design with..." goes on at some length about the problem and basically says that there is only one part from Abracom (sp?) that you can use. The doc doesn't even give a part number (it says TBA, I assume eventually they will) so I can't even check to see who has the part. I think the guys at eevblog are right that there is something off here. I've done a few switcher designs (far from an expert, for sure) and have never seen a polarity/orientation requirement for the inductor.
This all may well be much ado about nothing but I am hesitant to move forward with an RP235x design without a lot more clarity on this topic and, at the least, reasonably broad parts availability (especially for asian CMs). I hope to hear more from the RP design team soon.
This all may well be much ado about nothing but I am hesitant to move forward with an RP235x design without a lot more clarity on this topic and, at the least, reasonably broad parts availability (especially for asian CMs). I hope to hear more from the RP design team soon.
Interesting that the quote in the eevblog OP explains exactly where the problem lies, which various contributors either missed or are ignoring:Bit of a bashing going on at https://www.eevblog.com/forum/projects/ ... -polarity/https://datasheets.raspberrypi.com/rp23 ... rp2350.pdfIt turns out that the magnetic field emitting from a 'wrong way round' inductor interferes with the regulator output capacitor (C7), which in turn upsets the control circuitry within RP2350. With the inductor in the proper orientation, and the precise layout and component selections used here, then this problem goes away.
Statistics: Posted by phil from seattle — Tue Aug 13, 2024 7:21 pm
