W5500 not drawing power


I’ve assembled a new prototype board with the W5500 and it appears to never power up. I’ve double checked all the connections and I get 3.3v power where I expect it right up to the decoupling caps and after that nothing, and nothing on the 1.2v rail.

Ethernet cable and switch port is confirmed good, with auto-neg enabled, but the link light on the switch never illuminates.

The LC of my crystal is 18pF so allowing for 5pF Cstray, the crystal caps seem reasonable. Sadly I don’t own a oscilloscope that will measure up to 25Mhz to 100% confirm this.

The schematic was based on the reference design & Adafruit’s Ethernet FeatherWing.

I’ve attached a screenshot of that part of the board layout and schematic. C19 I get a clean 3.3V after that nothing.

Could this be a bad chip or is there something else I can check through first? Any thoughts are much appreciated.

Mistake in connecting RX. What state reset signal is in? And how did you assembled, and at which temperature?

Hi, what are you seeing about the RXn connections?
Reset is pulled up to 3.3v at power on.
Board was reflowed in a reflow oven and hit the correct solder profile through out. I’m getting continuity on expected circuits.

Reset is pulled up to 3.3v at power on.

Hmm actually that’s not quite true double checking it. The 3.3v regulator feeds the 3.3vD/VDD power plane via a 22uF decoupling cap and that rail is only at 0.6v, which won’t be enough to be seen high I’d guess. This must be an issue with the 3.3vD power plane.