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 66

2026-11-04 14:56 PST (2026-11-04T22:56:57Z UTC) · commit fbc5369 (fbc53693ff48117f66c84ca17d2c28a755caa1b8)

ADOPTED

expansion routing 1: GND pours extended into the strip (zone outlines y 0.3 -> -29.7 on F/In1/B, hw/refill_strip.py) + HV keepout notches carved from the moved U10 cluster’s HV copper extents (hw/notch_strip.py, rule areas as in notch.py). GND 51 -> 9 groups; clearance 2 (justified D1 pair) after an intermediate refill-only state read 10 (8 HV-vs-pour in the strip, results/audit-refill-candidate.txt) — the notch removed all 8. Rails untouched yet: +3V3D 40, +5V 27, +3V3A 13, +3V3D_CDR 10 groups.

Nets fully routednot recorded
Pins failednot recorded
Clearance violations2
Unconnected nets69
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

Top

Pass 66 — top

Bottom

Pass 66 — bottom

Intermediate audits: results/audit-refill-candidate.txt (pour extension only: GND 51->7, violations 2->10) and results/audit-notch-candidate.txt (after notch: violations back to 2, GND 7->9 — two GND pads inside the notch rects lost pour contact, left for stitch/repair).

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