I wrote: > Also, let's try to use IO_3V3 then. As a precaution, I'd add a 0R > before LDO34IN, so that it can be reworked to use Vsys in case > there are problems.
Joerg raised a few good points against this plan. He's too shy to post, so here's my summary: - current surges would propagate from CODEC_whatever to IO_3V3, possibly causing trouble, - inrush current on LDO3/4 would be drawn from the IO_3V3 capacitors, possibly causing trouble as well, - last but not least, while a DC-DC converter is generally more efficient than an LDO, this seems to be a case where they're pretty much on par: if Vbat is 3.9 V and we burn 0.6 V in the LDO to reach 3.3 V, that's 85% efficiency, just about the same we'd expect for the DC-DC converter. I've removed the section and added a rationale why it's not a great idea to use IO_3V3 in this case. - Werner _______________________________________________ gta02-core mailing list [email protected] https://lists.openmoko.org/mailman/listinfo/gta02-core
