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 19

2026-11-04 06:06 PST (2026-11-04T14:06:35Z UTC) · commit da3cc77 (da3cc774f61afa610f6e69f671032489068509bb)

ADOPTED

repair6 final state on the Freerouting board: sweep 1 connected 64 groups, sweep 2 connected 0 (residue is copper-walled, per results/diagnose-fr1r.log census: NO_EXIT 23, POCKET 14, WIDE_NO_GOAL 2 of 39 classified); run stopped during the provably futile identical sweep 3; board state is the sweep-2-end save

Nets fully routednot recorded
Pins failednot recorded
Clearance violations13
Unconnected nets30
Audit verdictFAIL

Routes — all copper layers and each layer

F.Cu
F.Cu — click the image to open the full-size SVG in a new tab.
F.Cu layerF.CuIn1.Cu layerIn1.CuIn2.Cu layerIn2.CuB.Cu layerB.Cu

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

Top

Pass 19 — top

Bottom

Pass 19 — bottom

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