SN74HC139 Dual 2-to-4 Decoder

{
  "schema_version": 1,
  "type": "component",
  "slug": "sn74hc139",
  "title": "SN74HC139 Dual 2-to-4 Decoder",
  "brief": "Dual 2-to-4 line decoder/demultiplexer with active-low outputs.",
  "version": "0.1.0",
  "license": "CC-BY-SA-4.0",
  "tags": [
    "logic",
    "decoder",
    "demultiplexer",
    "74hc",
    "ti",
    "soic-16"
  ],
  "component": {
    "mpn": "SN74HC139",
    "manufacturer": "Texas Instruments",
    "package": "SOIC-16",
    "pin_count": 16,
    "category": "Logic",
    "subcategory": "Decoder / Demultiplexer",
    "datasheet": "https://www.ti.com/lit/ds/symlink/sn74hc139.pdf",
    "parts": {
      "symbol": "sn74hc139.kicad_sym",
      "footprint": "sn74hc139.kicad_mod",
      "model_3d": "sn74hc139-etched.glb",
      "model_3d_plain": "sn74hc139.glb",
      "lbr": "sn74hc139.lbr",
      "model_3d_step": "sn74hc139-etched.step",
      "model_3d_step_plain": "sn74hc139.step"
    },
    "distributor_links": {},
    "pins": [
      {
        "number": "1",
        "name": "1G",
        "type": "input",
        "description": "Decoder 1 active-low enable (strobe). When high, all 1Y0-1Y3 outputs are forced high; when low, the selected output is driven low. Can be used as a data input in demultiplexing applications."
      },
      {
        "number": "2",
        "name": "1A",
        "type": "input",
        "description": "Decoder 1 select input A (LSB of the 2-bit address for decoder 1)."
      },
      {
        "number": "3",
        "name": "1B",
        "type": "input",
        "description": "Decoder 1 select input B (MSB of the 2-bit address for decoder 1)."
      },
      {
        "number": "4",
        "name": "1Y0",
        "type": "output",
        "description": "Decoder 1 active-low output 0. Driven low when 1G=L and (1B,1A)=(0,0); otherwise high. IOH = -4 mA / IOL = 4 mA at VCC = 4.5 V."
      },
      {
        "number": "5",
        "name": "1Y1",
        "type": "output",
        "description": "Decoder 1 active-low output 1. Driven low when 1G=L and (1B,1A)=(0,1); otherwise high."
      },
      {
        "number": "6",
        "name": "1Y2",
        "type": "output",
        "description": "Decoder 1 active-low output 2. Driven low when 1G=L and (1B,1A)=(1,0); otherwise high."
      },
      {
        "number": "7",
        "name": "1Y3",
        "type": "output",
        "description": "Decoder 1 active-low output 3. Driven low when 1G=L and (1B,1A)=(1,1); otherwise high."
      },
      {
        "number": "8",
        "name": "GND",
        "type": "power_in",
        "description": "Ground reference (0 V) for both decoders."
      },
      {
        "number": "9",
        "name": "2Y3",
        "type": "output",
        "description": "Decoder 2 active-low output 3. Driven low when 2G=L and (2B,2A)=(1,1); otherwise high."
      },
      {
        "number": "10",
        "name": "2Y2",
        "type": "output",
        "description": "Decoder 2 active-low output 2. Driven low when 2G=L and (2B,2A)=(1,0); otherwise high."
      },
      {
        "number": "11",
        "name": "2Y1",
        "type": "output",
        "description": "Decoder 2 active-low output 1. Driven low when 2G=L and (2B,2A)=(0,1); otherwise high."
      },
      {
        "number": "12",
        "name": "2Y0",
        "type": "output",
        "description": "Decoder 2 active-low output 0. Driven low when 2G=L and (2B,2A)=(0,0); otherwise high."
      },
      {
        "number": "13",
        "name": "2B",
        "type": "input",
        "description": "Decoder 2 select input B (MSB of the 2-bit address for decoder 2)."
      },
      {
        "number": "14",
        "name": "2A",
        "type": "input",
        "description": "Decoder 2 select input A (LSB of the 2-bit address for decoder 2)."
      },
      {
        "number": "15",
        "name": "2G",
        "type": "input",
        "description": "Decoder 2 active-low enable (strobe). When high, all 2Y0-2Y3 outputs are forced high; when low, the selected output is driven low. Can be used as a data input in demultiplexing applications."
      },
      {
        "number": "16",
        "name": "VCC",
        "type": "power_in",
        "description": "Positive supply, 2 V to 6 V (5 V nominal). Bypass with a 0.1 uF capacitor close to the pin (0.1 uF and 1 uF in parallel is common)."
      }
    ],
    "provenance": {
      "extractor": "ds2sf",
      "datasheet": {
        "url": "https://www.ti.com/lit/ds/symlink/sn74hc139.pdf",
        "pages": 30,
        "sha256": "7bed90a2f9c2fe80",
        "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": "74HC139",
      "logic_family": "74HC",
      "function_code": "139",
      "function_class": "Decoder",
      "function_name": "Dual 2-to-4 Line Decoder/Demultiplexer",
      "manufacturer": "Texas Instruments",
      "is_specialty": false
    },
    "models_3d": [
      {
        "file": "sn74hc139.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": "sn74hc139-etched.step",
        "role": "eda",
        "up": "Z",
        "units": "mm",
        "origin": "footprint origin = pad-pattern centre",
        "seat": "z = 0",
        "extents_mm": [
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        "zmin_mm": 0,
        "centre_offset_mm": 0,
        "footprint_binding": "identity",
        "sha256": "5f97d7ae88e4141f799138448fc5ca7b92cabaaffe218ad3dea54181cee8f218",
        "checked": "2026-10-07",
        "checked_by": "factory/step_pose.py (Z-up, origin, seat, binding)"
      }
    ]
  },
  "metadata": {
    "specs": {
      "Type": "Dual 2-to-4 decoder / demultiplexer",
      "Logic family": "74HC (CMOS)",
      "Outputs": "Active-low, one-of-four per decoder",
      "Supply voltage": "2 V to 6 V",
      "Propagation delay": "16 ns typ at 5 V",
      "Operating temperature": "-40 C to 85 C"
    }
  },
  "sections": [
    "hero",
    "viewers",
    "readme",
    "breadcrumbs",
    "info"
  ],
  "discovery_triggers": [
    "2-to-4 decoder",
    "demultiplexer",
    "address decode",
    "chip select generation"
  ],
  "discovery_pitch": "Two independent 2-to-4 decoders for address decoding and generating chip selects.",
  "author": {
    "name": "Ray"
  },
  "dependencies": {},
  "hero": {
    "type": "image",
    "path": "docs/hero.png"
  },
  "files": [
    "page.json",
    "README.md",
    "sn74hc139.kicad_sym",
    "sn74hc139.kicad_mod",
    "sn74hc139.glb",
    "sn74hc139.lbr",
    "docs/hero.png",
    "docs/sn74hc139-datasheet.pdf",
    "viewers/symbol.html",
    "viewers/footprint.html",
    "sn74hc139-etched.step"
  ],
  "variants": [
    {
      "mpn": "SN74HC139D",
      "kind": "unknown"
    },
    {
      "mpn": "SN74HC139DB",
      "kind": "unknown"
    },
    {
      "mpn": "SN74HC139N",
      "kind": "unknown"
    },
    {
      "mpn": "SN74HC139NS",
      "kind": "unknown"
    },
    {
      "mpn": "SN74HC139PW",
      "kind": "unknown"
    },
    {
      "mpn": "SN74HC139J",
      "kind": "unknown"
    },
    {
      "mpn": "SN74HC139W",
      "kind": "unknown"
    },
    {
      "mpn": "SN74HC139FK",
      "kind": "unknown"
    }
  ]
}