PDLVDS-RX — photodiode LVDS receiver

Clean-room receiver for the Miniscope Zero optical uplink: Excelitas C30737LH Si APD → OPA657 TIA → LMH7220 comparator (LVDS out, DAC-set threshold) → ADN2813 CDR → STM32H723 + USB3300 USB-HS. Design target: 50 Mbps line rate, 8b/10b (40 Mbps payload); the paper's mode: 8 Mbps Manchester (16 Mbaud), as transmitted. LT3757 flyback APD bias 150–420 V. USB-C powered; verify on any laptop over USB, no FPGA attached.

Pass 121

2026-11-05 15:03 PST (2026-11-05T23:03:34Z UTC) · commit ed32afa (ed32afaa472c114246b42c4c590841e9aefe96f4)

ADOPTED

+3V3A U7.25 connected (queue item 4): via d=0.45 at (77.98,11.65) in the north-east corner – overlaps U7.25’s own pad edge, clears U7.24 (ULPI_D0) by 0.25 shape distance, and touches the In2 mesh segment (77.88,11.62)->(77.62,11.88); F stub (77.80,11.75)->(77.98,11.65). Refused on record: via on the pad or onto the mesh NE (QFN pitch + ULPI_CK’s F staircase at 0.25 class on every site) and the F west channel run in 4 variants (ULPI_CK wall + CDR_DATP via (76.88,10.62) + XI/PHY_1V8A escape nubs tile the channel). DELTAS vs pass 120: nets 28->27 (+3V3A connected), violations 71->71, census byte-identical. No victims.

Nets fully routednot recorded
Pins failednot recorded
Clearance violations71
Unconnected nets27
Audit verdictFAIL

Routes — all copper layers and each layer

All layers
All layers — click the image to open the full-size SVG in a new tab.
All layersAll layers F.Cu layerF.CuIn1.Cu layerIn1.CuIn2.Cu layerIn2.CuB.Cu layerB.Cu

F.Cu In1.Cu In2.Cu B.Cu

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