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Doing a more extensive SI/PI workup on the switch line card in preparation for a) a blog update on the switch project and b) getting all my I's dotted and T's crossed before spending a lot of money stuffing three more boards and ordering the logic board.

Here's the 2.5V rail, putting out a bit over 2A at 2.5V. Ripple is dominated by ~300 kHz switching noise plus some harmonics of the 125 MHz PHY symbol rate (which makes sense this rail is driving the PHY PAM5 transceivers among other things).

But the amount of ripple is amazing! It's under 7 mV P-P and a microscopic 788 μV RMS.

And yet with the RP4030 active power rail probe, I can clearly see not only the switching ripple but the tiny transients at the zero crossing that are probably only about a mV high.