SN74HC123 Dual Monostable

{
  "schema_version": 1,
  "type": "component",
  "slug": "sn74hc123",
  "title": "SN74HC123 Dual Monostable",
  "brief": "Dual retriggerable monostable multivibrator (one-shot) with reset, 74HC CMOS.",
  "version": "0.1.0",
  "license": "CC-BY-SA-4.0",
  "tags": [
    "logic",
    "monostable",
    "one-shot",
    "retriggerable",
    "74hc",
    "ti",
    "soic-16"
  ],
  "component": {
    "mpn": "SN74HC123",
    "manufacturer": "Texas Instruments",
    "package": "SOIC-16",
    "pin_count": 16,
    "category": "Logic",
    "subcategory": "Monostable Multivibrator",
    "datasheet": "https://www.ti.com/lit/ds/symlink/cd74hc123.pdf",
    "parts": {
      "symbol": "sn74hc123.kicad_sym",
      "footprint": "sn74hc123.kicad_mod",
      "model_3d": "sn74hc123-etched.glb",
      "model_3d_plain": "sn74hc123.glb",
      "model_3d_step": "sn74hc123-etched.step",
      "model_3d_step_plain": "sn74hc123.step",
      "lbr": "sn74hc123.lbr"
    },
    "distributor_links": {},
    "pins": [
      {
        "number": "1",
        "name": "1A",
        "type": "input",
        "description": "Monostable 1 trailing-edge trigger input (active-low, Schmitt trigger). A high-to-low transition on 1A triggers the one-shot when 1B = H and 1R = H."
      },
      {
        "number": "2",
        "name": "1B",
        "type": "input",
        "description": "Monostable 1 leading-edge trigger input (active-high, Schmitt trigger). A low-to-high transition on 1B triggers the one-shot when 1A = L and 1R = H."
      },
      {
        "number": "3",
        "name": "1R",
        "type": "input",
        "description": "Monostable 1 reset input (active-low). Driving 1R low terminates the output pulse and holds 1Q = L, 1Q_bar = H. Must be tied high when unused."
      },
      {
        "number": "4",
        "name": "1Q_bar",
        "type": "output",
        "description": "Monostable 1 inverted (complementary) buffered output. Drives 10 LSTTL loads (15 LSTTL as a bus driver) over the -55 to 125 C range."
      },
      {
        "number": "5",
        "name": "2Q",
        "type": "output",
        "description": "Monostable 2 non-inverted buffered output. Pulse width tW = 0.45 * 2Rx * 2Cx at VCC = 5V."
      },
      {
        "number": "6",
        "name": "2Cx",
        "type": "passive",
        "description": "Monostable 2 external timing capacitor terminal. Connect Cx from this pin to 2RxCx (pin 7); the capacitor sets the output pulse width together with 2Rx."
      },
      {
        "number": "7",
        "name": "2RxCx",
        "type": "passive",
        "description": "Monostable 2 external Rx/Cx common node. Connect the external timing resistor from VCC to this pin and the timing capacitor between 2Cx (pin 6) and this pin. Minimum Rx ~5 kOhm, minimum Cx = 0 pF."
      },
      {
        "number": "8",
        "name": "GND",
        "type": "power_in",
        "description": "Device ground reference (0 V)."
      },
      {
        "number": "9",
        "name": "2A",
        "type": "input",
        "description": "Monostable 2 trailing-edge trigger input (active-low, Schmitt trigger). A high-to-low transition on 2A triggers the one-shot when 2B = H and 2R = H."
      },
      {
        "number": "10",
        "name": "2B",
        "type": "input",
        "description": "Monostable 2 leading-edge trigger input (active-high, Schmitt trigger). A low-to-high transition on 2B triggers the one-shot when 2A = L and 2R = H."
      },
      {
        "number": "11",
        "name": "2R",
        "type": "input",
        "description": "Monostable 2 reset input (active-low). Driving 2R low terminates the output pulse and holds 2Q = L, 2Q_bar = H. Must be tied high when unused."
      },
      {
        "number": "12",
        "name": "2Q_bar",
        "type": "output",
        "description": "Monostable 2 inverted (complementary) buffered output."
      },
      {
        "number": "13",
        "name": "1Q",
        "type": "output",
        "description": "Monostable 1 non-inverted buffered output. Pulse width tW = 0.45 * 1Rx * 1Cx at VCC = 5V."
      },
      {
        "number": "14",
        "name": "1Cx",
        "type": "passive",
        "description": "Monostable 1 external timing capacitor terminal. Connect Cx from this pin to 1RxCx (pin 15)."
      },
      {
        "number": "15",
        "name": "1RxCx",
        "type": "passive",
        "description": "Monostable 1 external Rx/Cx common node. Connect the external timing resistor from VCC to this pin and the timing capacitor between 1Cx (pin 14) and this pin."
      },
      {
        "number": "16",
        "name": "VCC",
        "type": "power_in",
        "description": "Positive supply. HC types: 2 V to 6 V. HCT types: 4.5 V to 5.5 V. Absolute max 7 V."
      }
    ],
    "provenance": {
      "extractor": "ds2sf",
      "datasheet": {
        "url": "https://www.ti.com/lit/ds/symlink/cd74hc123.pdf",
        "pages": 24,
        "sha256": "1ae45a9eac40347d",
        "source_tier": "mfr"
      },
      "cad": "KiCad official (CC-BY-SA 4.0)",
      "pins": {
        "total": 16,
        "described": 16,
        "cites_pages": true,
        "refuses_to_fabricate": true
      }
    },
    "viewers": {
      "symbol": "viewers/symbol.html",
      "footprint": "viewers/footprint.html"
    },
    "logic": {
      "family_id": "74HC123",
      "logic_family": "74HC",
      "function_code": "123",
      "function_class": "Multivibrator",
      "function_name": "Dual Retriggerable Monostable Multivibrator",
      "manufacturer": "Texas Instruments",
      "is_specialty": false
    },
    "models_3d": [
      {
        "file": "sn74hc123.step",
        "role": "plain",
        "up": "Z",
        "units": "mm",
        "origin": "footprint origin = pad-pattern centre",
        "seat": "z = 0",
        "extents_mm": [
          6,
          9.9,
          1.75
        ],
        "zmin_mm": 0,
        "centre_offset_mm": 0,
        "footprint_binding": "identity",
        "sha256": "d5eeddb4c0b304dc61950919b126fc61d7586abd5f16ab71a2a79759ec6498bf",
        "checked": "2026-10-07",
        "checked_by": "factory/step_pose.py (Z-up, origin, seat, binding)"
      },
      {
        "file": "sn74hc123-etched.step",
        "role": "eda",
        "up": "Z",
        "units": "mm",
        "origin": "footprint origin = pad-pattern centre",
        "seat": "z = 0",
        "extents_mm": [
          6,
          9.9,
          1.75
        ],
        "zmin_mm": 0,
        "centre_offset_mm": 0,
        "footprint_binding": "identity",
        "sha256": "5f772cd7fbd72f287fedb5cce0152a0e30e4b08409c8f47d3a2008b9794b39a0",
        "checked": "2026-10-07",
        "checked_by": "factory/step_pose.py (Z-up, origin, seat, binding)"
      }
    ]
  },
  "metadata": {
    "specs": {
      "Type": "Dual retriggerable monostable (one-shot)",
      "Logic family": "74HC (CMOS)",
      "Timing": "External R and C set pulse width",
      "Retriggerable": "Yes, with clear input",
      "Supply voltage": "2 V to 6 V",
      "Operating temperature": "-40 C to 85 C"
    }
  },
  "sections": [
    "hero",
    "viewers",
    "readme",
    "breadcrumbs",
    "info"
  ],
  "discovery_triggers": [
    "one-shot",
    "monostable",
    "pulse generator",
    "retriggerable timer",
    "edge to pulse"
  ],
  "discovery_pitch": "Two retriggerable one-shots that turn an edge into a timed pulse set by an external RC, with a clear input.",
  "author": {
    "name": "Ray"
  },
  "dependencies": {},
  "hero": {
    "type": "image",
    "path": "docs/hero.png"
  },
  "files": [
    "page.json",
    "README.md",
    "sn74hc123.kicad_sym",
    "sn74hc123.kicad_mod",
    "sn74hc123.glb",
    "sn74hc123.step",
    "sn74hc123.lbr",
    "docs/hero.png",
    "docs/sn74hc123-datasheet.pdf",
    "viewers/symbol.html",
    "viewers/footprint.html",
    "sn74hc123-etched.step"
  ],
  "variants": [
    {
      "mpn": "SN74HC123E",
      "kind": "unknown"
    },
    {
      "mpn": "SN74HC123M",
      "kind": "unknown"
    },
    {
      "mpn": "SN74HC123MT",
      "kind": "unknown"
    },
    {
      "mpn": "SN74HC123M96",
      "kind": "unknown"
    },
    {
      "mpn": "SN74HC123NSR",
      "kind": "unknown"
    },
    {
      "mpn": "SN74HC123PW",
      "kind": "unknown"
    },
    {
      "mpn": "SN74HC123PWR",
      "kind": "unknown"
    },
    {
      "mpn": "SN74HC123PWT",
      "kind": "unknown"
    },
    {
      "mpn": "SN74HC123F3A",
      "kind": "unknown"
    }
  ]
}