LM311

{
  "schema_version": 1,
  "type": "component",
  "slug": "lm311",
  "title": "LM311",
  "brief": "TI single precision voltage comparator, SOIC-8. Open-collector output, strobe, offset balance, single or split supply. Datasheet-verified.",
  "version": "0.1.0",
  "license": "CC-BY-SA-4.0",
  "tags": [
    "component",
    "comparator",
    "precision",
    "open-collector",
    "strobe",
    "soic-8",
    "texas-instruments"
  ],
  "component": {
    "mpn": "LM311",
    "manufacturer": "Texas Instruments",
    "package": "SOIC-8",
    "pin_count": 8,
    "category": "Comparator",
    "subcategory": "Precision voltage comparator",
    "datasheet": "https://www.ti.com/lit/ds/symlink/lm311.pdf",
    "parts": {
      "symbol": "lm311.kicad_sym",
      "footprint": "lm311.kicad_mod",
      "model_3d": "lm311-etched.glb",
      "model_3d_plain": "lm311.glb",
      "lbr": "lm311.lbr",
      "model_3d_step": "lm311-etched.step",
      "model_3d_step_plain": "lm311.step"
    },
    "distributor_links": {},
    "pins": [
      {
        "number": "1",
        "name": "EMIT OUT",
        "type": "output",
        "description": "Open-emitter output of the comparator's output transistor. Typically tied to VCC- (ground) or used as the low side of a level-shifted output; combined with COL OUT it forms a floating output that can drive loads referenced to either rail up to 50 V at 50 mA."
      },
      {
        "number": "2",
        "name": "IN+",
        "type": "input",
        "description": "Non-inverting comparator input. Differential input range +/-30 V (VID), single-ended input range must remain within |VI| <= 15 V and within VCC- + 0.5 V to VCC+ - 1.5 V for guaranteed operation. Input bias current typ 100 nA (max 250 nA at 25 C)."
      },
      {
        "number": "3",
        "name": "IN-",
        "type": "input",
        "description": "Inverting comparator input. Differential and common-mode limits identical to IN+; typical input offset voltage 2 mV, input offset current 6 nA at 25 C."
      },
      {
        "number": "4",
        "name": "VCC-",
        "type": "power_in",
        "description": "Negative supply pin. Absolute max -18 V; recommended supply span (VCC+ - VCC-) is 3.5 V to 30 V. In single-supply operation this pin is grounded."
      },
      {
        "number": "5",
        "name": "BALANCE",
        "type": "input",
        "description": "Offset-balance trim pin. Connect an external network (typically a potentiometer between BALANCE and BAL/STRB with wiper to VCC+) to null input offset voltage. May be left open when trimming is not required."
      },
      {
        "number": "6",
        "name": "BAL/STRB",
        "type": "input",
        "description": "Combined balance / strobe input. When current-driven at -3 mA to -5 mA (per datasheet note: the strobe must not be shorted to ground) the output is forced into the OFF (high-impedance) state regardless of the differential input. Also serves as the second terminal of the offset-balance network."
      },
      {
        "number": "7",
        "name": "COL OUT",
        "type": "output",
        "description": "Open-collector output of the comparator's output transistor. Withstands up to 50 V (VCC- + 50 V) with the emitter grounded; sinks up to 50 mA (VOL <= 1.5 V at IOL = 50 mA). Requires an external pull-up resistor for logic-level output."
      },
      {
        "number": "8",
        "name": "VCC+",
        "type": "power_in",
        "description": "Positive supply pin. Absolute max +18 V; recommended supply span (VCC+ - VCC-) is 3.5 V to 30 V. Positive-supply current ICC+ typ 5.1 mA (no load)."
      }
    ],
    "provenance": {
      "extractor": "ds2sf",
      "datasheet": {
        "url": "https://www.ti.com/lit/ds/symlink/lm311.pdf",
        "pages": 42,
        "sha256": "c4f907a0fa591db0",
        "source_tier": "mfr"
      },
      "cad": "KiCad official (CC-BY-SA 4.0)",
      "pins": {
        "total": 8,
        "described": 8,
        "cites_pages": true,
        "refuses_to_fabricate": true
      }
    },
    "viewers": {
      "symbol": "viewers/symbol.html",
      "footprint": "viewers/footprint.html"
    },
    "models_3d": [
      {
        "file": "lm311.step",
        "role": "plain",
        "up": "Z",
        "units": "mm",
        "origin": "footprint origin = pad-pattern centre",
        "seat": "z = 0",
        "extents_mm": [
          6,
          4.9,
          1.75
        ],
        "zmin_mm": 0,
        "centre_offset_mm": 0,
        "footprint_binding": "identity",
        "sha256": "07f46cff378d30e6c27dfd5a03092c795323f86d91c71fc7e743f4f418dc553a",
        "checked": "2026-10-07",
        "checked_by": "factory/step_pose.py (Z-up, origin, seat, binding)"
      },
      {
        "file": "lm311-etched.step",
        "role": "eda",
        "up": "Z",
        "units": "mm",
        "origin": "footprint origin = pad-pattern centre",
        "seat": "z = 0",
        "extents_mm": [
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          1.75
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        "zmin_mm": 0,
        "centre_offset_mm": 0,
        "footprint_binding": "identity",
        "sha256": "06ae36186355da7b2a6c6893759cca67ad34c02fb7c4ceea78779e52670f216c",
        "checked": "2026-11-03",
        "checked_by": "factory/step_pose.py (Z-up, origin, seat, binding)"
      }
    ]
  },
  "metadata": {
    "specs": {
      "Type": "Single precision comparator",
      "Output": "open-collector (separate emitter + collector)",
      "Output rating": "50 V / 50 mA",
      "Strobe": "yes (force output off)",
      "Offset trim": "balance pins",
      "Response time": "~200 ns",
      "Supply": "single 5 V or split up to ±15 V",
      "Package": "SOIC-8"
    }
  },
  "sections": [
    "hero",
    "viewers",
    "readme",
    "breadcrumbs",
    "info"
  ],
  "discovery_triggers": [
    "lm311",
    "precision comparator",
    "voltage comparator",
    "strobe comparator",
    "open collector comparator"
  ],
  "discovery_pitch": "LM311 single precision voltage comparator (SOIC-8) with datasheet-verified pinout, KiCad symbol/footprint/3D, and full provenance.",
  "author": {
    "name": "Ray"
  },
  "dependencies": {},
  "hero": {
    "type": "image",
    "path": "docs/hero.png"
  },
  "files": [
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    "README.md",
    "lm311.kicad_sym",
    "lm311.kicad_mod",
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    "lm311.lbr",
    "docs/hero.png",
    "docs/lm311-datasheet.pdf",
    "viewers/symbol.html",
    "viewers/footprint.html",
    "lm311-etched.step"
  ],
  "variants": [
    {
      "mpn": "LM311D (SOIC-8, tube)",
      "kind": "packaging"
    },
    {
      "mpn": "LM311DR (SOIC-8, tape & reel)",
      "kind": "packaging"
    }
  ]
}