BL7121AH

{
  "schema_version": 1,
  "type": "component",
  "slug": "bl7121ah",
  "title": "BL7121AH",
  "brief": "BL Shanghai Belling Digital Isolators, SOIC-8. Pinout extracted from the datasheet, KiCad symbol/footprint/3D.",
  "version": "0.2.0",
  "license": "CC-BY-SA-4.0",
  "tags": [
    "component",
    "comm-uart",
    "bl7121ah"
  ],
  "component": {
    "mpn": "BL7121AH",
    "manufacturer": "BL Shanghai Belling",
    "package": "SOIC-8",
    "pin_count": 8,
    "category": "Comm/UART",
    "subcategory": "Digital Isolators",
    "datasheet": "https://wmsc.lcsc.com/wmsc/upload/file/pdf/v2/lcsc/2309271714_BL-Shanghai-Belling-BL7121AH_C7436522.pdf",
    "parts": {
      "symbol": "bl7121ah.kicad_sym",
      "footprint": "bl7121ah.kicad_mod",
      "model_3d": "bl7121ah-etched.glb",
      "model_3d_plain": "bl7121ah.glb",
      "model_3d_step": "bl7121ah-etched.step",
      "model_3d_step_plain": "bl7121ah.step",
      "lbr": "bl7121ah.lbr"
    },
    "distributor_links": {},
    "pins": [
      {
        "number": "1",
        "name": "VDD1",
        "type": "power_in",
        "description": "Side 1 power supply, 2.5 V to 5.5 V (recommended). Requires a 0.1 uF bypass capacitor to GND1 close to the pin. Absolute max 6 V."
      },
      {
        "number": "2",
        "name": "VOA",
        "type": "output",
        "description": "Channel A digital output on side 1 (reverse channel). Referenced to VDD1/GND1. Drives IOH up to -4 mA / IOL up to 4 mA at 5 V supply. Default state is HIGH (AH suffix) when input power or signal is lost."
      },
      {
        "number": "3",
        "name": "VIB",
        "type": "input",
        "description": "Channel B digital input on side 1 (forward channel). Referenced to VDD1/GND1. VIH >= 0.7*VDD1, VIL <= 0.25*VDD1. High-Z if left open (output goes to default HIGH state)."
      },
      {
        "number": "4",
        "name": "GND1",
        "type": "power_in",
        "description": "Ground reference for side 1 (VDD1 domain). Isolated from GND2 by the SiO2 capacitive barrier (up to 3750 VRMS working isolation)."
      },
      {
        "number": "5",
        "name": "GND2",
        "type": "power_in",
        "description": "Ground reference for side 2 (VDD2 domain). Isolated from GND1 by the SiO2 capacitive barrier."
      },
      {
        "number": "6",
        "name": "VOB",
        "type": "output",
        "description": "Channel B digital output on side 2 (forward channel). Referenced to VDD2/GND2. Drives IOH up to -4 mA / IOL up to 4 mA at 5 V supply. Default state is HIGH (AH suffix) when input power or signal is lost."
      },
      {
        "number": "7",
        "name": "VIA",
        "type": "input",
        "description": "Channel A digital input on side 2 (reverse channel). Referenced to VDD2/GND2. VIH >= 0.7*VDD2, VIL <= 0.25*VDD2. High-Z if left open (output goes to default HIGH state)."
      },
      {
        "number": "8",
        "name": "VDD2",
        "type": "power_in",
        "description": "Side 2 power supply, 2.5 V to 5.5 V (recommended). Requires a 0.1 uF bypass capacitor to GND2 close to the pin. Absolute max 6 V."
      }
    ],
    "provenance": {
      "extractor": "ds2sf",
      "datasheet": {
        "url": "https://wmsc.lcsc.com/wmsc/upload/file/pdf/v2/lcsc/2309271714_BL-Shanghai-Belling-BL7121AH_C7436522.pdf",
        "pages": 13,
        "sha256": "b22900b73aef2795",
        "source_tier": "lcsc"
      },
      "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": "bl7121ah.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": "bl7121ah-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": "7db1f83a166b66c9e869aa5a104148ae6fe4e0e738d144898de6c74c1ae5b8c1",
        "checked": "2026-10-07",
        "checked_by": "factory/step_pose.py (Z-up, origin, seat, binding)"
      }
    ]
  },
  "metadata": {
    "specs": {
      "Manufacturer": "BL Shanghai Belling",
      "Package": "SOIC-8",
      "Category": "Comm/UART",
      "Pins": "8"
    }
  },
  "sections": [
    "hero",
    "viewers",
    "readme",
    "breadcrumbs",
    "info"
  ],
  "discovery_triggers": [
    "bl7121ah"
  ],
  "discovery_pitch": "BL7121AH (BL Shanghai Belling) component page with datasheet-verified CAD.",
  "author": {
    "name": "Ray",
    "email": "[email protected]"
  },
  "dependencies": {},
  "hero": {
    "type": "image",
    "path": "docs/hero.png"
  },
  "files": [
    "page.json",
    "README.md",
    "bl7121ah.kicad_sym",
    "bl7121ah.kicad_mod",
    "bl7121ah.glb",
    "bl7121ah.step",
    "bl7121ah-etched.step",
    "bl7121ah.lbr",
    "docs/hero.png",
    "docs/bl7121ah-datasheet.pdf",
    "viewers/symbol.html",
    "viewers/footprint.html"
  ],
  "visibility": {
    "public": true
  },
  "variants": [
    {
      "mpn": "BL7121AH",
      "kind": "packaging"
    }
  ],
  "updated_at": "2026-09-24T17:51:17.287Z"
}