ngscopeclient screenshot showing spiky ripple waveforms
https://files.ioc.exchange/media_attachments/files/112/029/992/498/927/264/original/f44dd247383d1ea0.png
3V3 is decidedly less pretty. This is the main 3.3V rail for the board.
It runs lots of stuff:
* Input to 3V0_N buck-boost
* Input to integrated buck on main MCU
* Main digital IO supply including QSPI from FPGA to MCU, and RGMII to baseT PHY
* Input for SFP+ filtering network
3.295V, 55.95 mV p-p / 2.21 mV RMS ripple.
I think this is still well within spec for everything but it's an EMC concern. I also just don't like rails looking this noisy.
I suspect those spikes are caused by the 3V0_N converter and will hopefully go away (or at least shrink) if I put some more input capacitance on it.
But we'll find out more once I probe 3V0_N and 3V3 simultaneously (planned for later).
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