UC3843M

{
  "schema_version": 1,
  "type": "component",
  "slug": "uc3843m",
  "title": "UC3843M",
  "brief": "HGSEMI AC-DC Controllers and Regulators, SOP-8. Pinout extracted from the datasheet, KiCad symbol/footprint/3D.",
  "version": "0.2.0",
  "license": "CC-BY-SA-4.0",
  "tags": [
    "component",
    "pmic",
    "uc3843m"
  ],
  "component": {
    "mpn": "UC3843M",
    "manufacturer": "HGSEMI",
    "package": "SOP-8",
    "pin_count": 8,
    "category": "PMIC",
    "subcategory": "AC-DC Controllers and Regulators",
    "datasheet": "https://datasheet.lcsc.com/datasheet/pdf/0621d38946e4edef125683f320a4fc33.pdf",
    "parts": {
      "symbol": "uc3843m.kicad_sym",
      "footprint": "uc3843m.kicad_mod",
      "model_3d": "uc3843m-etched.glb",
      "model_3d_plain": "uc3843m.glb",
      "model_3d_step": "uc3843m-etched.step",
      "model_3d_step_plain": "uc3843m.step",
      "lbr": "uc3843m.lbr"
    },
    "distributor_links": {},
    "pins": [
      {
        "number": "1",
        "name": "COMP",
        "type": "output",
        "description": "Error amplifier output. Used for loop compensation; an external RC network from COMP to VFB (pin 2) sets the compensation of the voltage feedback loop."
      },
      {
        "number": "2",
        "name": "VFB",
        "type": "input",
        "description": "Voltage feedback input - inverting input of the internal error amplifier. Typically connected to the switching power supply output through a resistor divider; internally compared against the 2.5 V reference."
      },
      {
        "number": "3",
        "name": "ISENSE",
        "type": "input",
        "description": "Current sense input. A voltage proportional to the switching inductor current is applied here (typically from a sense resistor Rs). The PWM latch resets and terminates the output pulse when this input exceeds ~1.0 V."
      },
      {
        "number": "4",
        "name": "RT/CT",
        "type": "passive",
        "description": "Oscillator timing pin. Connect RT from VREF (pin 8) to this pin, and CT from this pin to GND to set the oscillator frequency and maximum duty cycle. Maximum operating frequency up to 500 kHz."
      },
      {
        "number": "5",
        "name": "GND",
        "type": "power_in",
        "description": "Device ground. Common return for control-circuit bias current and reference for all internal voltages."
      },
      {
        "number": "6",
        "name": "OUTPUT",
        "type": "output",
        "description": "Totem-pole gate-drive output. Directly drives the gate of an external power MOSFET; capable of sourcing/sinking up to ±1 A peak. Held low when Vcc is below the UVLO threshold."
      },
      {
        "number": "7",
        "name": "VCC",
        "type": "power_in",
        "description": "Positive supply input for the IC. Operating range approximately 8.4 V (UVLO turn-on) to 30 V (absolute max); startup current <0.5 mA, operating supply current typ. 12 mA. Internal 34 V zener clamp on this pin."
      },
      {
        "number": "8",
        "name": "VREF",
        "type": "power_out",
        "description": "5.0 V precision reference output (4.90-5.10 V, 1 mA load). Provides charging current through RT to the timing capacitor CT and can supply external loads up to ~20 mA; short-circuit current typ. -100 mA."
      }
    ],
    "provenance": {
      "extractor": "ds2sf",
      "datasheet": {
        "url": "https://datasheet.lcsc.com/datasheet/pdf/0621d38946e4edef125683f320a4fc33.pdf",
        "pages": 10,
        "sha256": "549a60aef8d59c3f",
        "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"
    },
    "pin1": {
      "pad": "1",
      "at": [
        -2.475,
        -1.905
      ],
      "corner": "top-left",
      "source": "silk-marker",
      "derived_from": "SOIC-8_3.9x4.9mm_P1.27mm@sha256:074ecb2092b24fa4",
      "mark": "drawn"
    },
    "models_3d": [
      {
        "file": "uc3843m.step",
        "role": "plain",
        "up": "Z",
        "units": "mm",
        "origin": "footprint origin = pad-pattern centre",
        "seat": "z = 0",
        "extents_mm": [
          6,
          4.9,
          1.75
        ],
        "zmin_mm": 0,
        "centre_offset_mm": 0,
        "footprint_binding": "identity",
        "sha256": "07f46cff378d30e6c27dfd5a03092c795323f86d91c71fc7e743f4f418dc553a",
        "checked": "2026-10-07",
        "checked_by": "factory/step_pose.py (Z-up, origin, seat, binding)"
      },
      {
        "file": "uc3843m-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": "9c96d77f39a8223b0f1f77f69f68e4c194a7a429d509eca805ac329687971a5d",
        "checked": "2026-10-07",
        "checked_by": "factory/step_pose.py (Z-up, origin, seat, binding)"
      }
    ]
  },
  "metadata": {
    "specs": {
      "Manufacturer": "HGSEMI",
      "Package": "SOP-8",
      "Category": "PMIC",
      "Pins": "8"
    }
  },
  "sections": [
    "hero",
    "viewers",
    "readme",
    "breadcrumbs",
    "info"
  ],
  "discovery_triggers": [
    "uc3843m"
  ],
  "discovery_pitch": "UC3843M (HGSEMI) component page with datasheet-verified CAD.",
  "author": {
    "name": "Ray"
  },
  "dependencies": {},
  "hero": {
    "type": "image",
    "path": "docs/hero.png"
  },
  "files": [
    "page.json",
    "README.md",
    "uc3843m.kicad_sym",
    "uc3843m.kicad_mod",
    "uc3843m.glb",
    "uc3843m.step",
    "uc3843m-etched.step",
    "uc3843m.lbr",
    "docs/hero.png",
    "docs/uc3843m-datasheet.pdf",
    "viewers/symbol.html",
    "viewers/footprint.html"
  ],
  "visibility": {
    "public": true
  },
  "variants": [
    {
      "mpn": "UC3843MM/TR",
      "kind": "packaging"
    },
    {
      "mpn": "UC3843MN",
      "kind": "packaging"
    }
  ],
  "updated_at": "2026-09-25T13:31:39.762Z"
}