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 137

2026-11-05 21:58 PST (2026-11-06T05:58:33Z UTC) · commit 25ee047 (25ee0470a85dcf0a3fd1d2231f40cd23fd1a5860)

ADOPTED

Heal-stub prune after the U5 rip-and-relays. The +3V3D/CDR_DATP re-lays (passes 135-136) left fresh dangling stubs (track_dangling had risen 17 -> 22). Ran the DRC/graph prune (scratch/drc_graph_prune.py) on exp163: 23 dead segments removed over 9 rounds, every round refereed. KiCad DRC: violations 347 -> 338, track_dangling 22 -> 20, clearance 45 -> 44, shorting_items 34 UNCHANGED, unconnected items 48 UNCHANGED throughout. The 20 remaining dangling are the standing residue: graph-vetoed bridges (live overshoot tracks) + ambiguous hairline joints the matcher refuses to guess (SWCLK at (94.125,34.375) among them).

Nets fully routednot recorded
Pins failednot recorded
Clearance violations112
Unconnected nets34
Audit verdictFAIL

Routes — all copper layers and each layer

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

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

Top

Pass 137 — top

Bottom

Pass 137 — bottom

← Pass 136 · all passes · Pass 138 →