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 136

2026-11-05 21:52 PST (2026-11-06T05:52:35Z UTC) · commit 4590d4b (4590d4bb3baae2c86c1a822387921ce41f6d940f)

ADOPTED

U5 rip-and-relay, the big one: +3V3D. Ripped all 72 +3V3D segments intersecting the U5 pad-field box (x 61..71, y -26..-14) – the heal-era distribution whose stubs lay across U5’s GND/CDR_CLKP/CDR_CLKN pads – and re-laid with heal_nets (scratch/heal8 KiCad 8 copies): 10 groups connected in 121 s. KiCad DRC referee, exp161 -> exp163: violations 411 -> 347, shorting_items 54 -> 34 (every U5 +3V3D short gone; the 6 remaining +3V3D shorts are the separate east-edge LED-column locality at D6/D7/R44), unconnected items 50 -> 48 (the rip forced the rail’s genuinely split groups to re-merge), clearance 65 -> 45, solder_mask_bridge 72 -> 38. Cost: track_dangling 17 -> 22 (fresh heal stubs; the DRC/graph prune eats those next). No class but dangling regressed, and total violations fell by 64.

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

Routes — all copper layers and each layer

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

Top

Pass 136 — top

Bottom

Pass 136 — bottom

← Pass 135 · all passes · Pass 137 →