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 182

2026-11-06 17:10 PST (2026-11-07T01:10:27Z UTC) · commit b1f0d0e (b1f0d0ef6df4c40ccab803eb5488d32eb1578078)

ADOPTED

district prep: rip + re-lay ULPI_CK web (F escape that sealed the trio pad columns removed; stub to via (76.62,17.30); In2 joins the CK trunk at its north end (76.62,13.50)->(74.625,13.50), vertical trimmed) and PHY_1V8 web (B run moved y17.375 -> y16.20 so it no longer shadows the south-row via slots; F stub to via (78.10,17.50) d0.6; west joiner to C22.1 via (72.125,17.625) kept). Both nets stay connected; KiCad DRC delta ZERO (154 violations / 21 unconnected, class table identical to exp211). Trio/STP/USB_RST terminations deferred with proof (see tools commit): STP has no DRC-legal first dive while CK via + PHY stub stand; USB_RST F corridor closed (exclusions 0.31+0.425 > 0.707 corner spacing); heal/astar6 cannot cross the district ring in its model in either direction (445,790-cell flood, all 18 goal cells unvisited; reversed search exhausts in 3 s)

Nets fully routednot recorded
Pins failednot recorded
Clearance violations108
Unconnected nets18
Audit verdictFAIL

Routes — all copper layers and each layer

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

Top

Pass 182 — top

Bottom

Pass 182 — bottom

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