UC3845BD1R2G

{
  "schema_version": 1,
  "type": "component",
  "slug": "uc3845bd1r2g",
  "title": "UC3845BD1R2G",
  "brief": "onsemi AC-DC Controllers and Regulators, SOIC-8. Pinout extracted from the datasheet, KiCad symbol/footprint/3D.",
  "version": "0.2.0",
  "license": "CC-BY-SA-4.0",
  "tags": [
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  "component": {
    "mpn": "UC3845BD1R2G",
    "manufacturer": "onsemi",
    "package": "SOIC-8",
    "pin_count": 8,
    "category": "PMIC",
    "subcategory": "AC-DC Controllers and Regulators",
    "datasheet": "https://www.onsemi.com/pdf/datasheet/uc3845bd1r2-d.pdf",
    "parts": {
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      "lbr": "uc3845bd1r2g.lbr"
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    "distributor_links": {
      "lcsc": "C98715"
    },
    "pins": [
      {
        "number": "1",
        "name": "Compensation",
        "type": "output",
        "description": "Error amplifier output / compensation node. External RC network to Voltage Feedback (pin 2) sets the closed-loop gain and frequency response of the error amplifier used for output regulation."
      },
      {
        "number": "2",
        "name": "Voltage Feedback",
        "type": "input",
        "description": "Inverting input of the on-chip 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 (VFB regulation set point ~2.5 V)."
      },
      {
        "number": "3",
        "name": "Current Sense",
        "type": "input",
        "description": "Non-inverting input of the current-sense comparator. Monitors the MOSFET source current across a sense resistor; the internal PWM latch is reset (output terminates) when this pin reaches the threshold set by the error amp output (nominal max threshold 1.0 V)."
      },
      {
        "number": "4",
        "name": "RT/CT",
        "type": "passive",
        "description": "Oscillator timing pin. External resistor RT to Vref and timing capacitor CT to GND set the oscillator frequency (fOSC ≈ 1.72 / (RT·CT) for RT > 5 kΩ). Output switching frequency equals oscillator frequency."
      },
      {
        "number": "5",
        "name": "GND",
        "type": "power_in",
        "description": "Device ground and current return for control circuitry and totem-pole output stage. In the SOIC-8/PDIP-8 package the signal and power grounds share this pin (the SOIC-14 D-suffix splits them)."
      },
      {
        "number": "6",
        "name": "Output",
        "type": "output",
        "description": "High-current totem-pole gate-drive output for the external power MOSFET. Capable of ±1 A peak source/sink; typical VOH ≈ 13.5 V and VOL ≈ 0.1 V at 20 mA. Rise/fall times ~50 ns into 1 nF."
      },
      {
        "number": "7",
        "name": "VCC",
        "type": "power_in",
        "description": "Positive supply for the control IC and output driver. UVLO thresholds for the UC3845B are 8.5 V (on) / 7.6 V (off). Absolute max 36 V (internally zener-clamped); typical startup current 0.3 mA, operating current ~12 mA."
      },
      {
        "number": "8",
        "name": "Vref",
        "type": "power_out",
        "description": "Buffered 5.0 V ±1% precision reference output (4.95-5.05 V at 25 °C, 1 mA). Sources up to ~50 mA to bias external circuitry and to feed the oscillator timing resistor RT. Short-circuit protected (~85 mA typ)."
      }
    ],
    "provenance": {
      "extractor": "ds2sf",
      "datasheet": {
        "url": "https://www.onsemi.com/pdf/datasheet/uc3845bd1r2-d.pdf",
        "pages": 22,
        "sha256": "811d8a44f6a2a239",
        "source_tier": "mfr"
      },
      "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": [
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      "corner": "top-left",
      "source": "silk-marker",
      "derived_from": "SOIC-8_3.9x4.9mm_P1.27mm@sha256:074ecb2092b24fa4",
      "mark": "drawn"
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        "zmin_mm": 0,
        "centre_offset_mm": 0,
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        "sha256": "07f46cff378d30e6c27dfd5a03092c795323f86d91c71fc7e743f4f418dc553a",
        "checked": "2026-10-07",
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        "sha256": "ecbafa2b9ea8ecc55e63d5c0fd22fa8af8ed678862bbda25745fe1134aef93ad",
        "checked": "2026-10-07",
        "checked_by": "factory/step_pose.py (Z-up, origin, seat, binding)"
      }
    ]
  },
  "metadata": {
    "specs": {
      "Manufacturer": "onsemi",
      "Package": "SOIC-8",
      "Category": "PMIC",
      "Pins": "8"
    }
  },
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  "discovery_triggers": [
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  "discovery_pitch": "UC3845BD1R2G (onsemi) component page with datasheet-verified CAD.",
  "author": {
    "name": "Ray"
  },
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  "variants": [
    {
      "mpn": "UC3845BD1R2G",
      "kind": "packaging"
    },
    {
      "mpn": "UC3845BD1R2GD1G",
      "kind": "packaging"
    },
    {
      "mpn": "UC3845BD1R2GN",
      "kind": "packaging"
    },
    {
      "mpn": "UC3845BD1R2GNG",
      "kind": "packaging"
    },
    {
      "mpn": "UC3845BD1R2GD",
      "kind": "packaging"
    },
    {
      "mpn": "UC3845BD1R2GDG",
      "kind": "packaging"
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    {
      "mpn": "UC3845BD1R2GDR2G",
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  ],
  "updated_at": "2026-09-25T13:32:47.328Z"
}