UC3845BN

{
  "schema_version": 1,
  "type": "component",
  "slug": "uc3845bn",
  "title": "UC3845BN",
  "brief": "STMicroelectronics AC-DC Controllers and Regulators, DIP-8. Pinout extracted from the datasheet, KiCad symbol/footprint/3D.",
  "version": "0.2.0",
  "license": "CC-BY-SA-4.0",
  "tags": [
    "component",
    "pmic",
    "uc3845bn"
  ],
  "component": {
    "mpn": "UC3845BN",
    "manufacturer": "STMicroelectronics",
    "package": "DIP-8",
    "pin_count": 8,
    "category": "PMIC",
    "subcategory": "AC-DC Controllers and Regulators",
    "datasheet": "https://datasheet.lcsc.com/datasheet/pdf/f5f1fe2018fe4b0fb5140e98da46aa14.pdf",
    "parts": {
      "symbol": "uc3845bn.kicad_sym",
      "footprint": "uc3845bn.kicad_mod",
      "model_3d": "uc3845bn-etched.glb",
      "model_3d_plain": "uc3845bn.glb",
      "model_3d_step": "uc3845bn-etched.step",
      "model_3d_step_plain": "uc3845bn.step",
      "lbr": "uc3845bn.lbr"
    },
    "distributor_links": {
      "lcsc": "C5175"
    },
    "pins": [
      {
        "number": "1",
        "name": "COMP",
        "type": "output",
        "description": "Error amplifier output made available for loop compensation. Typically an RC network is connected between this pin and VFB (pin 2) to shape the control-loop response."
      },
      {
        "number": "2",
        "name": "VFB",
        "type": "input",
        "description": "Inverting input of the internal error amplifier. Normally connected to the switching power supply output through a resistor divider; the non-inverting input is internally tied to the 2.5 V reference."
      },
      {
        "number": "3",
        "name": "ISENSE",
        "type": "input",
        "description": "Current-sense input. A voltage proportional to the primary/inductor current is applied here; the PWM comparator terminates the output switch conduction when this pin reaches the error-amp-derived threshold (max input signal ~1 V, gain 3 V/V)."
      },
      {
        "number": "4",
        "name": "RT/CT",
        "type": "passive",
        "description": "Oscillator timing pin. A resistor RT from this pin to VREF and a capacitor CT from this pin to GROUND set the oscillator frequency and the maximum output duty cycle. Operation up to 500 kHz is possible."
      },
      {
        "number": "5",
        "name": "GROUND",
        "type": "power_in",
        "description": "Common control-circuitry and power-stage return. All voltages in the datasheet are referenced to this pin; timing and bypass capacitors must connect close to this pin in a single-point ground."
      },
      {
        "number": "6",
        "name": "OUTPUT",
        "type": "output",
        "description": "High-current totem-pole gate-drive output for an external N-channel power MOSFET. Peak source/sink currents up to 1 A; typical rise/fall times ~50 ns into 1 nF."
      },
      {
        "number": "7",
        "name": "VCC",
        "type": "power_in",
        "description": "Positive supply of the control IC (labeled Vi in the block diagram/absolute-maximum table). Max 30 V (self-limiting via internal ~36 V zener). UVLO turn-on 8.5 V typ, turn-off 7.9 V typ; operating supply current ~12 mA typ."
      },
      {
        "number": "8",
        "name": "VREF",
        "type": "power_out",
        "description": "Buffered 5.0 V reference output (5 V, 50 mA capable). Provides charging current for the timing capacitor CT through the timing resistor RT and can bias external circuitry."
      }
    ],
    "provenance": {
      "extractor": "ds2sf",
      "datasheet": {
        "url": "https://datasheet.lcsc.com/datasheet/pdf/f5f1fe2018fe4b0fb5140e98da46aa14.pdf",
        "pages": 15,
        "sha256": "62066370bcc6f048",
        "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": [
        0,
        0
      ],
      "corner": "bottom-right",
      "source": "fab-chamfer",
      "derived_from": "DIP-8_W7.62mm@sha256:222fb44370968119",
      "mark": "synthesised"
    },
    "models_3d": [
      {
        "file": "uc3845bn.step",
        "role": "plain",
        "up": "Z",
        "units": "mm",
        "origin": "footprint origin = pad-pattern centre",
        "seat": "body on z = 0, through-hole leads below",
        "extents_mm": [
          7.874,
          9.27,
          6.98
        ],
        "zmin_mm": -3.3,
        "centre_offset_mm": 0,
        "footprint_binding": "identity",
        "sha256": "4a377a56a8d9e9c0b86c095ef9ecc1869ac19e7f5069a3247b294250bf4f235d",
        "checked": "2026-10-07",
        "checked_by": "factory/step_pose.py (Z-up, origin, seat, binding)"
      },
      {
        "file": "uc3845bn-etched.step",
        "role": "eda",
        "up": "Z",
        "units": "mm",
        "origin": "footprint origin = pad-pattern centre",
        "seat": "body on z = 0, through-hole leads below",
        "extents_mm": [
          7.874,
          9.27,
          6.98
        ],
        "zmin_mm": -3.3,
        "centre_offset_mm": 0,
        "footprint_binding": "identity",
        "sha256": "ac3ec9ab11708c35aef683a2344937279e51448ee13663c28f3f367a32d0ca4f",
        "checked": "2026-10-07",
        "checked_by": "factory/step_pose.py (Z-up, origin, seat, binding)"
      }
    ]
  },
  "metadata": {
    "specs": {
      "Manufacturer": "STMicroelectronics",
      "Package": "DIP-8",
      "Category": "PMIC",
      "Pins": "8"
    }
  },
  "sections": [
    "hero",
    "viewers",
    "readme",
    "breadcrumbs",
    "info"
  ],
  "discovery_triggers": [
    "uc3845bn"
  ],
  "discovery_pitch": "UC3845BN (STMicroelectronics) component page with datasheet-verified CAD.",
  "author": {
    "name": "Ray"
  },
  "dependencies": {},
  "hero": {
    "type": "image",
    "path": "docs/hero.png"
  },
  "files": [
    "page.json",
    "README.md",
    "uc3845bn.kicad_sym",
    "uc3845bn.kicad_mod",
    "uc3845bn.glb",
    "uc3845bn.step",
    "uc3845bn-etched.step",
    "uc3845bn.lbr",
    "docs/hero.png",
    "docs/uc3845bn-datasheet.pdf",
    "viewers/symbol.html",
    "viewers/footprint.html"
  ],
  "visibility": {
    "public": true
  },
  "variants": [
    {
      "mpn": "UC3845BNN",
      "kind": "packaging"
    },
    {
      "mpn": "UC3845BND1",
      "kind": "packaging"
    }
  ],
  "updated_at": "2026-09-25T13:33:03.838Z"
}