{
  "meta": {
    "title": "Dual-Rail Power Tree",
    "version": "1.0"
  },
  "symbols": {},
  "instances": [
    { "ref": "J1", "part": "connector", "properties": { "value": "VIN/GND" }, "placement": { "x": null, "y": null, "rotation": 0, "locked": false } },
    { "ref": "U1", "part": "generic", "properties": { "value": "Buck 12V->5V" }, "placement": { "x": null, "y": null, "rotation": 0, "locked": false } },
    { "ref": "U2", "part": "generic", "properties": { "value": "LDO 5V->3V3" }, "placement": { "x": null, "y": null, "rotation": 0, "locked": false } },
    { "ref": "U3", "part": "generic", "properties": { "value": "MCU" }, "placement": { "x": null, "y": null, "rotation": 0, "locked": false } },
    { "ref": "U4", "part": "generic", "properties": { "value": "RF Module" }, "placement": { "x": null, "y": null, "rotation": 0, "locked": false } },
    { "ref": "C1", "part": "capacitor", "properties": { "value": "22uF" }, "placement": { "x": null, "y": null, "rotation": 0, "locked": false } },
    { "ref": "C2", "part": "capacitor", "properties": { "value": "10uF" }, "placement": { "x": null, "y": null, "rotation": 0, "locked": false } },
    { "ref": "C3", "part": "capacitor", "properties": { "value": "100nF" }, "placement": { "x": null, "y": null, "rotation": 0, "locked": false } },
    { "ref": "C4", "part": "capacitor", "properties": { "value": "100nF" }, "placement": { "x": null, "y": null, "rotation": 0, "locked": false } }
  ],
  "nets": [
    { "name": "VIN", "class": "power", "nodes": [ { "ref": "J1", "pin": "1" }, { "ref": "U1", "pin": "VIN" } ] },
    { "name": "5V", "class": "power", "nodes": [ { "ref": "U1", "pin": "VOUT" }, { "ref": "U2", "pin": "VIN" }, { "ref": "C1", "pin": "1" }, { "ref": "C2", "pin": "1" } ] },
    { "name": "3V3", "class": "power", "nodes": [ { "ref": "U2", "pin": "VOUT" }, { "ref": "U3", "pin": "VCC" }, { "ref": "U4", "pin": "VCC" }, { "ref": "C3", "pin": "1" }, { "ref": "C4", "pin": "1" } ] },
    { "name": "GND", "class": "ground", "nodes": [ { "ref": "J1", "pin": "2" }, { "ref": "U1", "pin": "GND" }, { "ref": "U2", "pin": "GND" }, { "ref": "U3", "pin": "GND" }, { "ref": "U4", "pin": "GND" }, { "ref": "C1", "pin": "2" }, { "ref": "C2", "pin": "2" }, { "ref": "C3", "pin": "2" }, { "ref": "C4", "pin": "2" } ] },
    { "name": "SPI_CLK", "class": "clock", "nodes": [ { "ref": "U3", "pin": "SCLK" }, { "ref": "U4", "pin": "SCLK" } ] },
    { "name": "SPI_MOSI", "class": "signal", "nodes": [ { "ref": "U3", "pin": "MOSI" }, { "ref": "U4", "pin": "MOSI" } ] },
    { "name": "SPI_MISO", "class": "signal", "nodes": [ { "ref": "U3", "pin": "MISO" }, { "ref": "U4", "pin": "MISO" } ] }
  ],
  "constraints": {
    "groups": [
      { "name": "source", "members": ["J1", "U1", "C1"], "layout": "cluster" },
      { "name": "regulation", "members": ["U2", "C2"], "layout": "cluster" },
      { "name": "load", "members": ["U3", "U4", "C3", "C4"], "layout": "cluster" }
    ]
  },
  "annotations": [
    { "text": "Power-chain fixture with SPI branch used for readability QA.", "x": 24, "y": 24 }
  ]
}