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 83

2026-11-05 00:42 PST (2026-11-05T08:42:33Z UTC) · commit 606fe0c (606fe0ca4da53274880547211bbc552439377fe2)

ADOPTED

HV hops landed (hw/hops2.py on exp33 -> exp35): the predecessor’s crashed surgery, rebased and completed. HV_R31A, HV_R31B, HV_R29M hops placed direct; GND stitch re-laid on In2 to clear the R29M corridor; R48 moved + HV_R30M In2 underpass; APD_K fence ripped (24 segs) and B.Cu re-feed placed (final via refused in-script by HV_FBX – heal takes APD_K next); TP_HV re-stitch: hops.py’s diagonal was geometrically impossible (crosses R50.2’s 1.0 mm shadow) and the x=39.38 slot is empty at the 1.0 need – routed F east at y=2.2, In2 drop at x=44.46 (0.3 internal need), via up at (44.9,-7.6), stub into R34.2; tail island deleted. Audit (corrected checker): nets 43 -> 39, violations 87 -> 67. Known residue in this state: TP_HV still audits 2 groups – the In2 run ends at (44.46,-7.6), 0.14 mm short of the moved via at (44.9,-7.6); the link segment lands next pass. TP_HV zone grazes (8 lines) queue for the notch campaign.

Nets fully routednot recorded
Pins failednot recorded
Clearance violations67
Unconnected nets39
Audit verdictFAIL

Routes — all copper layers and each layer

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

Top

Pass 83 — top

Bottom

Pass 83 — bottom

← Pass 82 · all passes · Pass 84 →