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 123

2026-11-05 16:01 PST (2026-11-06T00:01:14Z UTC) · commit 29ad408 (29ad40873e999f6f1cb2a73941a3270ef74ac310)

ADOPTED

Batch heal over all 24 remaining nets (heal starts from each net’s SMALL group; several small groups sit in open grid even when the far end is sealed): ULPI_D1, ULPI_D3 (3 vias, 75s search) and ULPI_D6 CONNECTED – the ULPI knot loses three members; +5V closed two of its four groups (7-item group via 1 via; 2-item group direct), leaving [U7.4 group] vs main. All other nets refused by heal (pad-cell seals at the QFP/QFN rows; CF2/DP_PHY/HV_SS/PHY_1V8A/ULPI_D2 searches exhausted the 1.5M cap against enclosed target pockets). DELTAS vs pass 122: nets 27->24 (D1, D3, D6), violations 71->71, census byte-identical – heal’s grid routes audited clean. No victims. LEFT: 24 nets; knot remainder D2/D5/STP + USB_RST; named residuals XI, XO, +3V3D_CDR, CDR_LOL unchanged.

Nets fully routednot recorded
Pins failednot recorded
Clearance violations71
Unconnected nets24
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 123 — top

Bottom

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