MCP2221A USB Bridge

{
  "schema_version": 1,
  "type": "component",
  "slug": "mcp2221a",
  "title": "MCP2221A USB Bridge",
  "brief": "USB-2.0 to UART and I2C bridge with GPIO, ADC, and DAC, appears as a CDC + HID composite device.",
  "version": "0.1.0",
  "license": "CC-BY-SA-4.0",
  "tags": [
    "usb",
    "uart",
    "i2c",
    "bridge",
    "gpio",
    "microchip",
    "soic-14"
  ],
  "component": {
    "mpn": "MCP2221A",
    "manufacturer": "Microchip",
    "package": "SOIC-14",
    "pin_count": 14,
    "category": "Interface",
    "subcategory": "USB Bridge",
    "datasheet": "https://ww1.microchip.com/downloads/en/DeviceDoc/MCP2221A-Data-Sheet-DS20005565D.pdf",
    "parts": {
      "symbol": "mcp2221a.kicad_sym",
      "footprint": "mcp2221a.kicad_mod",
      "model_3d": "mcp2221a-etched.glb",
      "model_3d_plain": "mcp2221a.glb",
      "lbr": "mcp2221a.lbr",
      "model_3d_step": "mcp2221a-etched.step",
      "model_3d_step_plain": "mcp2221a.step"
    },
    "distributor_links": {},
    "pins": [
      {
        "number": "1",
        "name": "VDD",
        "type": "power_in",
        "description": "Positive supply input, 3.0V to 5.5V operating range. Decouple with a local ceramic capacitor."
      },
      {
        "number": "2",
        "name": "GP0",
        "type": "bidirectional",
        "description": "General purpose I/O. Alternate functions: SSPND (OUT) signals USB Suspend state; LED_URx (OUT, factory default) indicates UART Rx activity."
      },
      {
        "number": "3",
        "name": "GP1",
        "type": "bidirectional",
        "description": "General purpose I/O. Alternate functions: CLKR clock reference output (12 MHz or configurable divide), ADC1 input, LED_UTx (factory default) UART Tx activity indicator, and IOC external interrupt edge detector."
      },
      {
        "number": "4",
        "name": "RST",
        "type": "input",
        "description": "Active-low reset input with internal pull-up. Drive low to reset the device."
      },
      {
        "number": "5",
        "name": "URx",
        "type": "input",
        "description": "UART receive data input. Accepts data from the external UART peer to be forwarded to the USB CDC interface."
      },
      {
        "number": "6",
        "name": "UTx",
        "type": "output",
        "description": "UART transmit data output. Drives data received over the USB CDC interface to the external UART peer."
      },
      {
        "number": "7",
        "name": "GP2",
        "type": "bidirectional",
        "description": "General purpose I/O. Alternate functions: USBCFG (OUT, factory default) indicates USB enumeration complete; ADC2 analog input; DAC1 analog output."
      },
      {
        "number": "8",
        "name": "GP3",
        "type": "bidirectional",
        "description": "General purpose I/O. Alternate functions: LED_I2C (OUT, factory default) USB/I2C traffic indicator; ADC3 analog input; DAC2 analog output."
      },
      {
        "number": "9",
        "name": "SDA",
        "type": "bidirectional",
        "description": "I2C serial data line (open-drain). Requires external pull-up. MCP2221A operates as I2C host up to 400 kHz."
      },
      {
        "number": "10",
        "name": "SCL",
        "type": "bidirectional",
        "description": "I2C serial clock line (open-drain). Requires external pull-up. Driven by the MCP2221A as I2C host, up to 400 kHz."
      },
      {
        "number": "11",
        "name": "VUSB",
        "type": "power_out",
        "description": "USB internal 3.3V regulator output. Must be locally bypassed with a high-quality ceramic capacitor. Do not use to power external loads."
      },
      {
        "number": "12",
        "name": "D-",
        "type": "bidirectional",
        "description": "USB differential data line, negative. Connect to the D- line of the USB connector. Termination is integrated."
      },
      {
        "number": "13",
        "name": "D+",
        "type": "bidirectional",
        "description": "USB differential data line, positive. Connect to the D+ line of the USB connector. Termination is integrated."
      },
      {
        "number": "14",
        "name": "VSS",
        "type": "power_in",
        "description": "Device ground reference."
      }
    ],
    "provenance": {
      "extractor": "ds2sf",
      "datasheet": {
        "url": "https://ww1.microchip.com/downloads/en/DeviceDoc/MCP2221A-Data-Sheet-DS20005565D.pdf",
        "pages": 78,
        "sha256": "ade28a45a0314e2f",
        "source_tier": "mfr"
      },
      "cad": "KiCad official (CC-BY-SA 4.0)",
      "pins": {
        "total": 14,
        "described": 14,
        "cites_pages": true,
        "refuses_to_fabricate": true
      }
    },
    "viewers": {
      "symbol": "viewers/symbol.html",
      "footprint": "viewers/footprint.html"
    },
    "models_3d": [
      {
        "file": "mcp2221a.step",
        "role": "plain",
        "up": "Z",
        "units": "mm",
        "origin": "footprint origin = pad-pattern centre",
        "seat": "z = 0",
        "extents_mm": [
          6,
          8.7,
          1.75
        ],
        "zmin_mm": 0,
        "centre_offset_mm": 0,
        "footprint_binding": "identity",
        "sha256": "3b9a775da256c8afcc28dcddfbc2eb3f266107fe61ce8446d96f2c52b6f44a70",
        "checked": "2026-10-07",
        "checked_by": "factory/step_pose.py (Z-up, origin, seat, binding)"
      },
      {
        "file": "mcp2221a-etched.step",
        "role": "eda",
        "up": "Z",
        "units": "mm",
        "origin": "footprint origin = pad-pattern centre",
        "seat": "z = 0",
        "extents_mm": [
          6,
          8.7,
          1.75
        ],
        "zmin_mm": 0,
        "centre_offset_mm": 0,
        "footprint_binding": "identity",
        "sha256": "698211528c90bfcce19308889ee87563ffa5e6165b88b010223abf206a085726",
        "checked": "2026-10-07",
        "checked_by": "factory/step_pose.py (Z-up, origin, seat, binding)"
      }
    ]
  },
  "metadata": {
    "specs": {
      "Type": "USB-to-UART + USB-to-I2C bridge",
      "USB": "Full-speed USB 2.0 (12 Mb/s), CDC + HID composite",
      "UART": "Up to 460.8 kbaud",
      "I2C": "Master, up to 400 kHz",
      "GPIO": "4 pins with ADC (10-bit) and DAC (5-bit) functions",
      "Supply voltage": "3.0 V to 5.5 V",
      "Operating temperature": "-40 C to 85 C"
    }
  },
  "sections": [
    "hero",
    "viewers",
    "readme",
    "breadcrumbs",
    "info"
  ],
  "discovery_triggers": [
    "USB to UART",
    "USB to I2C",
    "USB serial bridge",
    "add USB to a project",
    "USB GPIO"
  ],
  "discovery_pitch": "Add USB to a design and get a UART, an I2C master, and a few GPIO/ADC/DAC pins, no custom driver needed.",
  "author": {
    "name": "Ray"
  },
  "dependencies": {},
  "hero": {
    "type": "image",
    "path": "docs/hero.png"
  },
  "files": [
    "page.json",
    "README.md",
    "mcp2221a.kicad_sym",
    "mcp2221a.kicad_mod",
    "mcp2221a.glb",
    "mcp2221a.lbr",
    "docs/hero.png",
    "docs/mcp2221a-datasheet.pdf",
    "viewers/symbol.html",
    "viewers/footprint.html",
    "mcp2221a-etched.step"
  ],
  "variants": [
    {
      "mpn": "MCP2221AI/P",
      "kind": "unknown"
    },
    {
      "mpn": "MCP2221AI/SL",
      "kind": "unknown"
    },
    {
      "mpn": "MCP2221AI/ST",
      "kind": "unknown"
    },
    {
      "mpn": "MCP2221AI/ML",
      "kind": "unknown"
    }
  ]
}