LMC555 CMOS Timer

{
  "schema_version": 1,
  "type": "component",
  "slug": "lmc555",
  "title": "LMC555 CMOS Timer",
  "brief": "CMOS version of the 555 timer with low power, high frequency, and single-supply operation.",
  "version": "0.1.0",
  "license": "CC-BY-SA-4.0",
  "tags": [
    "timer",
    "555",
    "cmos",
    "low-power",
    "oscillator",
    "ti",
    "soic-8"
  ],
  "component": {
    "mpn": "LMC555",
    "manufacturer": "Texas Instruments",
    "package": "SOIC-8",
    "pin_count": 8,
    "category": "Analog",
    "subcategory": "Timer",
    "datasheet": "https://www.ti.com/lit/ds/symlink/lmc555.pdf",
    "parts": {
      "symbol": "lmc555.kicad_sym",
      "footprint": "lmc555.kicad_mod",
      "model_3d": "lmc555-etched.glb",
      "model_3d_plain": "lmc555.glb",
      "model_3d_step": "lmc555-etched.step",
      "model_3d_step_plain": "lmc555.step",
      "lbr": "lmc555.lbr"
    },
    "distributor_links": {},
    "pins": [
      {
        "number": "1",
        "name": "GND",
        "type": "power_in",
        "description": "Ground reference voltage (0 V return for the supply)."
      },
      {
        "number": "2",
        "name": "TRIGGER",
        "type": "input",
        "description": "Trigger input responsible for transition of the internal flip-flop from set to reset. The output pulse of the timer depends on the amplitude of the external trigger pulse applied to this pin. Trigger threshold is nominally 1/3 V+."
      },
      {
        "number": "3",
        "name": "OUTPUT",
        "type": "output",
        "description": "Output driven waveform. Sources/sinks up to 10 mA (VS=5 V) or 50 mA (VS=12 V) to directly drive TTL and CMOS loads."
      },
      {
        "number": "4",
        "name": "RESET",
        "type": "input",
        "description": "Active-low reset. A negative pulse applied to this pin disables/resets the timer. When not used for reset purposes, connect this pin to V+ to avoid false triggering. Typical VRES = 0.7 V at VS = 1.5 V."
      },
      {
        "number": "5",
        "name": "CONTROL_VOLTAGE",
        "type": "input",
        "description": "Control-voltage input sets the internal threshold and trigger levels (nominally 2/3 V+). An external voltage applied here modulates the output pulse width/waveform. Typically decoupled to ground with 0.01 uF when unused."
      },
      {
        "number": "6",
        "name": "THRESHOLD",
        "type": "input",
        "description": "Threshold comparator input; compared against an internal reference of 2/3 V+. The voltage at this pin sets the reset state of the internal flip-flop."
      },
      {
        "number": "7",
        "name": "DISCHARGE",
        "type": "output",
        "description": "Open-collector (open-drain) discharge pin that shorts the external timing capacitor to ground between intervals (in phase with OUTPUT). Toggles the output from high to low when THRESHOLD reaches 2/3 V+."
      },
      {
        "number": "8",
        "name": "V+",
        "type": "power_in",
        "description": "Positive supply voltage with respect to ground. Operating range 1.5 V to 15 V."
      }
    ],
    "provenance": {
      "extractor": "ds2sf",
      "datasheet": {
        "url": "https://www.ti.com/lit/ds/symlink/lmc555.pdf",
        "pages": 35,
        "sha256": "993be6e487fb5fe6",
        "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": "lmc555.step",
        "role": "plain",
        "up": "Z",
        "units": "mm",
        "origin": "footprint origin = pad-pattern centre",
        "seat": "z = 0",
        "extents_mm": [
          6.0,
          4.9,
          1.75
        ],
        "zmin_mm": -0.0,
        "centre_offset_mm": 0.0,
        "footprint_binding": "identity",
        "sha256": "07f46cff378d30e6c27dfd5a03092c795323f86d91c71fc7e743f4f418dc553a",
        "checked": "2026-10-07",
        "checked_by": "factory/step_pose.py (Z-up, origin, seat, binding)"
      },
      {
        "file": "lmc555-etched.step",
        "role": "eda",
        "up": "Z",
        "units": "mm",
        "origin": "footprint origin = pad-pattern centre",
        "seat": "z = 0",
        "extents_mm": [
          6.0,
          4.9,
          1.75
        ],
        "zmin_mm": -0.0,
        "centre_offset_mm": 0.0,
        "footprint_binding": "identity",
        "sha256": "4d95b1fe32162766722eca1ba985443cca67475b402d75bc06a0afd2c4a535f2",
        "checked": "2026-10-07",
        "checked_by": "factory/step_pose.py (Z-up, origin, seat, binding)"
      }
    ]
  },
  "metadata": {
    "specs": {
      "Type": "CMOS timer (555-type)",
      "Supply voltage": "1.5 V to 15 V",
      "Max frequency": "3 MHz",
      "Supply current": "100 uA typ at 5 V",
      "Modes": "Astable, monostable",
      "Timing": "External R and C",
      "Operating temperature": "-40 C to 85 C"
    }
  },
  "sections": [
    "hero",
    "viewers",
    "readme",
    "breadcrumbs",
    "info"
  ],
  "discovery_triggers": [
    "555 timer",
    "CMOS 555",
    "oscillator",
    "pulse generator",
    "monostable timer"
  ],
  "discovery_pitch": "A low-power CMOS 555 that oscillates to 3 MHz and runs down to 1.5 V, for timers, PWM, and pulse generation.",
  "author": {
    "name": "Ray",
    "email": "[email protected]"
  },
  "dependencies": {},
  "hero": {
    "type": "image",
    "path": "docs/hero.png"
  },
  "files": [
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    "README.md",
    "lmc555.kicad_sym",
    "lmc555.kicad_mod",
    "lmc555.glb",
    "lmc555.step",
    "lmc555.lbr",
    "docs/hero.png",
    "docs/lmc555-datasheet.pdf",
    "viewers/symbol.html",
    "viewers/footprint.html",
    "lmc555-etched.step"
  ],
  "variants": [
    {
      "mpn": "LMC555D",
      "kind": "unknown"
    },
    {
      "mpn": "LMC555DGK",
      "kind": "unknown"
    },
    {
      "mpn": "LMC555P",
      "kind": "unknown"
    },
    {
      "mpn": "LMC555YBF",
      "kind": "unknown"
    },
    {
      "mpn": "LMC555YPB",
      "kind": "unknown"
    }
  ]
}