Thanks so much for the feedback - I've replaced the crystal with the ABM8-272-T3 recommended in the datasheet.Your crystal circuit doesn't seem to follow guidelines - not the recommended crystal, and the series resistor seems to be missing.
Extra 100nF on the regulator aren't needed for the regulator's sake, but do no harm. More important is when you come to layout to get the other 100nF that you do have in the right place for the RP2040 (including the path for ground current, which many designs posted here seem to do badly).
NCP1117 is a rather old and inefficient regulator (6mA quiescent current!); no doubt it will work but personally I'd use something better - AP2127 for example.
I've also removed the 100nF caps on LDO as it sounds like they are unnecessary..
Regarding the correct 100nF, are you referring to C10 in the schematic, and placing it close to RP2040 VREG_IN pin?
Many thanks too for the note regarding the NCP1117 - I took the example from the RP2040 hardware assembly but it sounds like it's not very efficient so I'll look into switching it with an alternative that others suggested e.g. AP2127 or LDL1117
Statistics: Posted by Pure1108 — Wed Nov 19, 2025 6:15 am