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 118

2026-11-05 13:55 PST (2026-11-05T21:55:19Z UTC) · commit 1c4fe11 (1c4fe11964d26d9a6aa11a52f18d8371670b2edb)

ADOPTED

GND islands closed (queue item 2): all 4 groups merged to 1. Stitch vias to the In1 GND plane (stitch_track.py): cluster track@(83.375,0.125), C34.2 tail track@(29.775,-2.25); hand_via via stub for the lone R32.2 pad (via (30.77,-3.80)). DELTAS vs pass 117: nets 30->29 (GND connected), violations 74->74 – census byte-identical (the R32.2-vs-R31.1 1.0 mm line is pad-placement geometry, carried to the violation campaign). No victims. Also this session: APD_K RJ2.2 leg (item 1, leg 3) stands as a named residual – hand_stub/hand_via/heal x2/thread_far gate/exact via-scan all refused and the APD_A_ALT crossing-swap dive site was refused on +3V3D/FB_3V3/GND blockers; untried mechanisms are a full connector-corner re-fanout or an RJ1/RJ2 move. Tooling: heal crash on In1 copper fixed with regression test in commit 8ffdef7.

Nets fully routednot recorded
Pins failednot recorded
Clearance violations74
Unconnected nets29
Audit verdictFAIL

Routes — all copper layers and each layer

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

Top

Pass 118 — top

Bottom

Pass 118 — bottom

← Pass 117 · all passes · Pass 119 →