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 115

2026-11-05 12:44 PST (2026-11-05T20:44:51Z UTC) · commit cac7c75 (cac7c75ba6182a55ca0e537bcabcbae3ea3f7dee)

ADOPTED

HV_FBX repaid (owed from pass 114). Ripped group 1’s 9-track F.Cu spur west of (33.25,-4.5) – the dead-end branch whose north end stopped 1.33 mm short of group 0’s In2 run with the only via site inside R31.1’s APD_K 1.0 mm disc (pass 114’s refused repay). Bridge landed on B.Cu via-to-via: (26.125,-4.625) group-0 via -> (30,-5.0) -> (33.875,-5.375) group-1 via, w=0.3. Refused on evidence first: F corridors y=-4.80/-5.05 (GND tail track x=30.38, y -4.975..-3.025), F y=-5.50 (R50.1 HV_R31B 1.0 mm disc), In2 via-to-via (HV_R31A run fills the In2 corridor). DELTAS vs pass 114: nets 31->30 (HV_FBX joined), violations 83->75 (-8: every APD_K-vs-HV_FBX spur line removed; census diff shows 0 new lines). No victims.

Nets fully routednot recorded
Pins failednot recorded
Clearance violations75
Unconnected nets30
Audit verdictFAIL

Routes — all copper layers and each layer

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

Top

Pass 115 — top

Bottom

Pass 115 — bottom

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