{
  "boardSha256": "aed3c21115ce28efa26a2609798bec3272e3077d0a4fe804864d1c743207ed32",
  "qualification": "Geometry/process review only; no physical assembly or yield evidence.",
  "smtPiecesBySide": {
    "B.Cu": 30,
    "F.Cu": 13
  },
  "qfn": {
    "reference": "U601",
    "pitchMm": 0.65,
    "exposedCopperAreaMm2": 11.559999999999999,
    "pasteWindowCount": 4,
    "pasteAreaMm2": 7.292997579680057,
    "pasteCoveragePercent": 63.088214357093925,
    "minimumPerimeterApertureAreaToWallAreaByStencilThicknessMm": {
      "0.1": 1.1943472861742257,
      "0.127": 0.9404309339954534,
      "0.15": 0.7962315241161506
    },
    "centralVias": [
      {
        "atMm": [
          135.0,
          69.3
        ],
        "diameterMm": 0.6,
        "drillMm": 0.3,
        "note": "Native through-via; no filled/capped process established."
      }
    ],
    "openQuestions": [
      "Choose stencil thickness and paste using measured print/reflow results.",
      "Review solder wicking/voiding at the central through-via; mask tenting is not filling/capping.",
      "Do not simply delete the via: via-removal-experiment.json records a native connectivity regression.",
      "Establish hidden-pad inspection and rework capability; a working UART alone does not inspect the pad."
    ]
  },
  "factoryAssemblyPlan": {
    "service": "JLC Standard double-sided SMT; all 43 placements are factory fitted.",
    "top": "13 fitted parts, including TP901/TP902 Keystone power loops.",
    "bottom": "30 fitted parts, including six Keystone rail/UART/GND loops.",
    "processQualification": "Supplier must confirm two-sided reflow sequence, heavy socket retention, stencil/paste and actual part thermal limits.",
    "customerAssembly": "Only the documented module headers, modules and mechanical hardware; no test-point hand soldering.",
    "notYetProven": "Supplier DFM/placement approval, QFN hidden-pad inspection, USB shell solder fill and first-article powered operation."
  },
  "sources": [
    {
      "path": "reference/pdfs/Microchip-AN2089-QFN-assembly.pdf",
      "url": "https://ww1.microchip.com/downloads/en/Appnotes/00002089A.pdf",
      "scope": "Generic package mounting/profile/moisture handling, not SEC1210-specific process approval."
    },
    {
      "path": "reference/pdfs/GCT-USB4125.pdf",
      "scope": "Drawing page 1: selected -0190 shell stake 1.90 mm; current PCB 1.60 mm."
    }
  ]
}