LM4040 Precision Voltage Reference

{
  "schema_version": 1,
  "type": "component",
  "slug": "lm4040",
  "title": "LM4040 Precision Voltage Reference",
  "brief": "Precision shunt (2-terminal) voltage reference, fixed output grades from 2.048 V to 10 V.",
  "version": "0.1.0",
  "license": "CC-BY-SA-4.0",
  "tags": [
    "voltage-reference",
    "shunt",
    "precision",
    "analog",
    "ti",
    "sot-23"
  ],
  "component": {
    "mpn": "LM4040",
    "manufacturer": "Texas Instruments",
    "package": "SOT-23",
    "pin_count": 3,
    "category": "Analog",
    "subcategory": "Voltage Reference",
    "datasheet": "https://www.ti.com/lit/ds/symlink/lm4040.pdf",
    "parts": {
      "symbol": "lm4040.kicad_sym",
      "footprint": "lm4040.kicad_mod",
      "model_3d": "lm4040-etched.glb",
      "model_3d_plain": "lm4040.glb",
      "lbr": "lm4040.lbr",
      "model_3d_step": "lm4040-etched.step",
      "model_3d_step_plain": "lm4040.step"
    },
    "distributor_links": {},
    "pins": [
      {
        "number": "1",
        "name": "CATHODE",
        "type": "passive",
        "description": "Shunt current/voltage input (cathode, marked '+'). Tie through a bias resistor R_S to V_S; the pin regulates at V_KA (2.048V-10V per grade) with cathode current I_Z in the 45µA-15mA range. Absolute maximum continuous cathode current is 25mA; minimum -10mA."
      },
      {
        "number": "2",
        "name": "ANODE",
        "type": "passive",
        "description": "Common pin (anode, marked '-'), normally connected to ground / circuit common. Return path for the shunt current I_Z."
      },
      {
        "number": "3",
        "name": "NC",
        "type": "unconnected",
        "description": "No internal connection (marked '*'). Must float or be tied to ANODE. TI recommends connecting to ANODE in high-EMI environments (near transformers or high-frequency switching noise)."
      }
    ],
    "provenance": {
      "extractor": "ds2sf",
      "datasheet": {
        "url": "https://www.ti.com/lit/ds/symlink/lm4040.pdf",
        "pages": 62,
        "sha256": "f59930cb71bcc890",
        "source_tier": "mfr"
      },
      "cad": "KiCad official (CC-BY-SA 4.0)",
      "pins": {
        "total": 3,
        "described": 3,
        "cites_pages": true,
        "refuses_to_fabricate": true
      }
    },
    "viewers": {
      "symbol": "viewers/symbol.html",
      "footprint": "viewers/footprint.html"
    },
    "models_3d": [
      {
        "file": "lm4040.step",
        "role": "plain",
        "up": "Z",
        "units": "mm",
        "origin": "footprint origin = pad-pattern centre",
        "seat": "z = 0",
        "extents_mm": [
          2.5,
          3,
          1.2
        ],
        "zmin_mm": 0,
        "centre_offset_mm": 0,
        "footprint_binding": "identity",
        "sha256": "dd5d1711204e1d8d26cd11490923bd84340820baa69538c385a4300ec2539bc0",
        "checked": "2026-10-07",
        "checked_by": "factory/step_pose.py (Z-up, origin, seat, binding)"
      },
      {
        "file": "lm4040-etched.step",
        "role": "eda",
        "up": "Z",
        "units": "mm",
        "origin": "footprint origin = pad-pattern centre",
        "seat": "z = 0",
        "extents_mm": [
          2.5,
          3,
          1.2
        ],
        "zmin_mm": 0,
        "centre_offset_mm": 0,
        "footprint_binding": "identity",
        "sha256": "82368dda56fcd41c1e94c94ccca44742e8fded17319024c7f19cc2b2c7748dbb",
        "checked": "2026-10-07",
        "checked_by": "factory/step_pose.py (Z-up, origin, seat, binding)"
      }
    ]
  },
  "metadata": {
    "specs": {
      "Type": "Shunt (2-terminal) voltage reference",
      "Output voltage": "Fixed grades 2.048 V to 10 V (2.5 V shown)",
      "Initial accuracy": "0.1% to 1% depending on grade",
      "Reverse current range": "60 uA to 15 mA",
      "Temp coefficient": "100 ppm/C max (typical grade)",
      "Package": "SOT-23 (DBZ), 3-lead",
      "Operating temperature": "-40 C to 85 C"
    }
  },
  "sections": [
    "hero",
    "viewers",
    "readme",
    "breadcrumbs",
    "info"
  ],
  "discovery_triggers": [
    "voltage reference",
    "ADC reference",
    "shunt reference",
    "precision bias"
  ],
  "discovery_pitch": "A two-terminal precision reference that sets a stable ADC or bias voltage with just a series resistor.",
  "author": {
    "name": "Ray"
  },
  "dependencies": {},
  "hero": {
    "type": "image",
    "path": "docs/hero.png"
  },
  "files": [
    "page.json",
    "README.md",
    "lm4040.kicad_sym",
    "lm4040.kicad_mod",
    "lm4040.glb",
    "lm4040.lbr",
    "docs/hero.png",
    "docs/lm4040-datasheet.pdf",
    "viewers/symbol.html",
    "viewers/footprint.html",
    "lm4040-etched.step"
  ],
  "variants": [
    {
      "mpn": "LM4040DBZ",
      "kind": "unknown"
    },
    {
      "mpn": "LM4040DBZR",
      "kind": "unknown"
    },
    {
      "mpn": "LM4040DBZT",
      "kind": "unknown"
    },
    {
      "mpn": "LM4040DCK",
      "kind": "unknown"
    },
    {
      "mpn": "LM4040DCKR",
      "kind": "unknown"
    },
    {
      "mpn": "LM4040DCKT",
      "kind": "unknown"
    },
    {
      "mpn": "LM4040LP",
      "kind": "unknown"
    },
    {
      "mpn": "LM4040LPR",
      "kind": "unknown"
    },
    {
      "mpn": "LM4040LPM",
      "kind": "unknown"
    }
  ]
}