LTC4121EUD#TRPBF

{
  "slug": "ltc4121eud-trpbf",
  "version": "0.1.0",
  "type": "component",
  "description": "Analog Devices Battery Management ICs, QFN-16-EP(3x3). Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.",
  "tags": [
    "component",
    "power management ics",
    "ltc4121eud#trpbf",
    "factory-2.0.0",
    "extractor-text"
  ],
  "dependencies": {},
  "hero": {
    "type": "image",
    "path": "docs/hero.png"
  },
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    "README.md",
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    "ltc4121eud-trpbf.kicad_mod",
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    "ltc4121eud-trpbf.step",
    "ltc4121eud-trpbf.lbr",
    "docs/hero.png",
    "docs/ltc4121eud-trpbf-datasheet.pdf",
    "viewers/symbol.html",
    "viewers/footprint.html",
    "ltc4121eud-trpbf-hero.glb",
    "ltc4121eud-trpbf-hero.overlay.json",
    "ltc4121eud-trpbf-etched.glb"
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  "component": {
    "mpn": "LTC4121EUD#TRPBF",
    "manufacturer": "Analog Devices",
    "package": "QFN-16-EP(3x3)",
    "pin_count": 17,
    "category": "Power Management ICs",
    "subcategory": "Battery Management ICs",
    "datasheet": "https://www.analog.com/media/en/technical-documentation/data-sheets/4121fbc.pdf",
    "parts": {
      "symbol": "ltc4121eud-trpbf.kicad_sym",
      "footprint": "ltc4121eud-trpbf.kicad_mod",
      "model_3d": "ltc4121eud-trpbf-hero.glb",
      "model_3d_plain": "ltc4121eud-trpbf-etched.glb",
      "model_3d_step": "ltc4121eud-trpbf-etched.step",
      "model_3d_step_plain": "ltc4121eud-trpbf.step",
      "lbr": "ltc4121eud-trpbf.lbr"
    },
    "distributor_links": {
      "lcsc": "C687336",
      "digikey": "LTC4121EUD#TRPBFTR-ND",
      "mouser": "584-LTC4121EUD#TRPBF"
    },
    "distributor_check": {
      "checked_at": "2026-10-30T11:59:38Z",
      "source": "Component Ocean /api/assign-pns",
      "digikey": {
        "pn": "LTC4121EUD#TRPBFTR-ND",
        "status": "found"
      },
      "mouser": {
        "pn": "584-LTC4121EUD#TRPBF",
        "status": "found",
        "lifecycle": "Restricted Availability"
      }
    },
    "pins": [
      {
        "number": "1",
        "name": "INTVCC",
        "type": "power_out",
        "description": "Output of the internal LDO from IN that supplies the gate drivers and ILOWBAT; needs a 2.2µF low-ESR capacitor to GND and no external load other than the NTC bias network."
      },
      {
        "number": "2",
        "name": "BOOST",
        "type": "passive",
        "description": "Boosted supply pin; connect a 22nF boost capacitor from this pin to SW."
      },
      {
        "number": "3",
        "name": "IN",
        "type": "power_in",
        "description": "Positive input supply (4.4V to 40V); decouple to GND with a 10µF or larger low-ESR capacitor that must settle within the ~36ms MPPT sample pulse."
      },
      {
        "number": "4",
        "name": "SW",
        "type": "output",
        "description": "Switch pin delivering power from IN to BAT through the step-down regulator; connect an inductor from SW to CHGSNS."
      },
      {
        "number": "5",
        "name": "GND",
        "type": "power_in",
        "description": "Ground pin; connect to the Exposed Pad, which must be soldered to PCB GND."
      },
      {
        "number": "6",
        "name": "MPPT",
        "type": "input",
        "description": "Input voltage regulation programming pin; connect a resistive divider from VIN to MPPT to GND, or tie to INTVCC or IN through at least 10k if unused, keeping parasitic capacitance minimal."
      },
      {
        "number": "7",
        "name": "FREQ",
        "type": "input",
        "description": "Switching frequency select: INTVCC for 1.5MHz or GND for 750kHz; do not float."
      },
      {
        "number": "8",
        "name": "CHGSNS",
        "type": "passive",
        "description": "Battery charge current sense pin, connected through the internal 0.3Ω sense resistor to BAT; connect the inductor from SW to this pin."
      },
      {
        "number": "9",
        "name": "BAT",
        "type": "bidirectional",
        "description": "Battery output pin that delivers charge current through the internal sense resistor and sources ILOWBAT for preconditioning; decouple with a low-ESR 22µF ceramic capacitor to GND."
      },
      {
        "number": "10",
        "name": "FB",
        "type": "input",
        "description": "Battery voltage feedback pin regulated to 2.4V; set float voltage (3.5V to 18V) with a divider from BAT to FB to FBG, ideally 588k Thevenin resistance to cancel the 25nA bias current."
      },
      {
        "number": "11",
        "name": "FBG",
        "type": "passive",
        "description": "Feedback ground pin that presents a low resistance RFBG to GND when sensing the battery and is high impedance in disabled or shutdown modes."
      },
      {
        "number": "12",
        "name": "NTC",
        "type": "input",
        "description": "Input to the thermistor monitoring circuit, needing a bias resistor from INTVCC and an NTC thermistor to GND; tie to GND to disable NTC qualified charging."
      },
      {
        "number": "13",
        "name": "PROG",
        "type": "passive",
        "description": "Charge current program and monitor pin; connect a 1% resistor of 3.01k (400mA) to 24.3k (50mA) to GND, regulates to 1.227V in constant-current mode with ICHG = hPROG·VPROG/RPROG."
      },
      {
        "number": "14",
        "name": "CHRG",
        "type": "output",
        "description": "Open-drain charge status output that is pulled low while charging and high impedance at timer expiry or when charge current falls below 10% of the programmed value; sinks up to 5mA and can be pulled up to IN."
      },
      {
        "number": "15",
        "name": "FAULT",
        "type": "output",
        "description": "Open-drain fault status output pulled low for an NTC temperature fault or bad battery fault; sinks up to 5mA and can be pulled up to IN."
      },
      {
        "number": "16",
        "name": "RUN",
        "type": "input",
        "description": "Run pin: below VEN (2.45V rising) the device is disabled and below VSD it enters shutdown; use a divider from VIN to program the charging enable voltage and do not float."
      },
      {
        "number": "17",
        "name": "GND",
        "type": "power_in",
        "description": "Exposed pad is GND and must be soldered to PCB GND for low electrical and thermal impedance (θJA 54°C/W)."
      }
    ],
    "provenance": {
      "extractor": "extract_pins 0.3",
      "factory_chain": {
        "factory": "2.0.0",
        "extractor": "extract_pins 0.3",
        "primary_model": "claude-sonnet-5-5",
        "primary_mode": "text",
        "consensus_model": "claude-sonnet-5-5",
        "consensus": "agreed",
        "guards": "pin_guards 0.1: passed",
        "guard_notes": [
          "extractor flagged: MPN LTC4121EUD#TRPBF is the programmable-float LTC4121 (not -4.2), so pin 10 is FB and pin 11 is FBG"
        ],
        "pages_sent": 12,
        "cost_usd": 0.1655,
        "at": "2026-10-30T11:59:21"
      },
      "datasheet": {
        "url": "https://www.analog.com/media/en/technical-documentation/data-sheets/4121fbc.pdf",
        "pages": 30,
        "sha256": "637cc566763ce54c",
        "source_tier": "mfr"
      },
      "cad": "KiCad official (CC-BY-SA 4.0)",
      "pins": {
        "total": 17,
        "described": 17,
        "cites_pages": true,
        "refuses_to_fabricate": true
      }
    },
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    "models_3d": [
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        "role": "plain",
        "up": "Z",
        "units": "mm",
        "origin": "footprint origin = pad-pattern centre",
        "seat": "z = 0",
        "extents_mm": [
          3.0,
          3.0,
          0.785
        ],
        "zmin_mm": 0.0,
        "centre_offset_mm": 0.0,
        "footprint_binding": "identity",
        "sha256": "3eb81ffac423a66cdcfead8efe56401da171edaf1f2257049aad7b2d3900f6c8",
        "checked": "2026-10-30",
        "checked_by": "factory/step_pose.py (Z-up, origin, seat, binding)"
      },
      {
        "file": "ltc4121eud-trpbf-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": 0.0,
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        "footprint_binding": "identity",
        "sha256": "96ffc0eadae7f9ca1b3661278d7a3316c7369c60ffa20c5d05b706108a979a83",
        "checked": "2026-10-30",
        "checked_by": "factory/step_pose.py (Z-up, origin, seat, binding)"
      }
    ],
    "package_dims": {
      "package_code": "UD16",
      "source_page": 28,
      "D": {
        "nom_mm": 3.0,
        "range_mm": [
          null,
          null
        ]
      },
      "E1": {
        "nom_mm": 3.0,
        "range_mm": [
          null,
          null
        ]
      },
      "e": {
        "nom_mm": 0.5,
        "range_mm": [
          null,
          null
        ]
      },
      "A": {
        "nom_mm": 0.7,
        "range_mm": [
          null,
          null
        ]
      },
      "source": "datasheet package drawing, every number found on its page (extract_pins --task dims)",
      "model_check": {
        "file": "ltc4121eud-trpbf.step",
        "verdict": "PASS",
        "reasons": [
          "height within the datasheet's package drawing"
        ],
        "by": "factory/package_fit.py"
      }
    }
  }
}