3 ms·
Hot tip: Ignore the RP2350 design sheet and use a standard 1.2V LDO in to provide the internal vCore - you save having to use that weird inductor and can clock
by boznz 6mo ago
Hot tip: Ignore the RP2350 design sheet and use a standard 1.2V LDO in to provide the internal vCore - you save having to use that weird inductor and can clock it at a 300Mhz much more reliably at 1.2V.
- Lerc 6mo agoWhat was the reasoning behind that? Were there specific features of that inductor that led them to choose it, or did they choose it and then found some of their design relied on atypical generic inductor behaviour. The problem with going off design sheet is you don't know what might change. There's usually a good chance that you are not depending on the difference, but it's the not knowing that gets to you.
- phire 6mo agoThey are suggesting bypassing the RP2350's internal switching regulator (which only needs an external coil and some caps) and replacing it with an external linear regulator (which is actually supported by the datasheet) Switching regulators have much lower power draw (which is important when running off batteries) and generate less heat, which sometimes leads to a more compact footprint (though I'm not sure the RP2350's core uses enough power for that benefit to kick in) The power/heat savings don't really matter for this usecase, and linear regulators have the advantage of producing more stable power, though you are hardwiring it to 1.2v (a small overvolt) rather than using the ability of the internal regulator to adjust its voltage on the fly (adjustable from 0.55c to 3.30v)
- boznz 6mo agoExactly this. Also having the regulator off chip reduces the heat a teeny bit.
- QuantumNomad_ 6mo agoSounds more like a cool tip than a hot tip to me in that case ;)