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 76

2026-11-04 20:43 PST (2026-11-05T04:43:58Z UTC) · commit 2462a08 (2462a08a722e35cf02148bf6dc16423677aff155)

ADOPTED

thread_far round 1 (exp12 -> exp13): the exact lattice threader with its pair gate raised 3 -> 15 mm (hw/thread_far.py) — 7 pairs threaded: CDR_VREF (gap 3.81, rips 2), REFCLKN (6.04, rips 2), SLICEP (4.46, rips 0), HV_SS (4.08, rips 3), HV_GATE (3.87, rips 1 — a diagnose-NO_EXIT group), HV_INTVCC (5.27, rips 3), +5V (0.19, rips 0). Proven en route: heal’s astar6 fails this residue at cap 1.5M AND at 15M (heal_big probe on CDR_VREF, 162 s, 0 connected) while the diagnostic BFS reaches the goal halo — the grid A* model, not the geometry, refuses these hops. Failure classes pinned by the parent: CLASS A = NO_EXIT pads (local surgery per pad, blocker named — queue in WORKING_NOTES), CLASS B = two-island long hauls (ULPI x8, CDR chain, CAP, APD_K — the parallel Freerouting lane’s territory; U6-side respread authorized if FR loses and diagnosis indicts U6 exits). 11 ripped victim items are repaid inside the class fixes, not by undirected heal sweeps. D1 exemption: STOPPED at the evidence gate (docs/07) — the 2 D1 lines remain violations as written.

Nets fully routednot recorded
Pins failednot recorded
Clearance violations17
Unconnected nets28
Audit verdictFAIL

Routes — all copper layers and each layer

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

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