LTC4040EUFD#TRPBF

{
  "slug": "ltc4040eufd-trpbf",
  "version": "0.1.0",
  "type": "component",
  "description": "Analog Devices Battery Management, VQFN-24-EP(4x5). Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.",
  "tags": [
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    "power management (pmic)",
    "ltc4040eufd#trpbf",
    "factory-2.0.0",
    "extractor-text"
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  "component": {
    "mpn": "LTC4040EUFD#TRPBF",
    "manufacturer": "Analog Devices",
    "package": "VQFN-24-EP(4x5)",
    "pin_count": 25,
    "category": "Power Management (PMIC)",
    "subcategory": "Battery Management",
    "datasheet": "https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8589863999937814528",
    "parts": {
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    },
    "distributor_links": {
      "lcsc": "C687163",
      "digikey": "LTC4040EUFD#TRPBFTR-ND",
      "mouser": "584-LTC4040EUFDTRPBF"
    },
    "distributor_check": {
      "checked_at": "2026-10-18T06:47:17Z",
      "source": "Component Ocean /api/assign-pns",
      "digikey": {
        "pn": "LTC4040EUFD#TRPBFTR-ND",
        "status": "found",
        "lifecycle": "Active"
      },
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        "pn": "584-LTC4040EUFDTRPBF",
        "status": "found"
      }
    },
    "pins": [
      {
        "number": "1",
        "name": "VSYS",
        "type": "power_out",
        "description": "System voltage output that powers the external load from the input supply or the backup battery and charges the battery when input power is available; bypass with a low-ESR ceramic capacitor of at least 100µF to GND."
      },
      {
        "number": "2",
        "name": "PROG",
        "type": "passive",
        "description": "Charge current program pin where an external resistor to ground sets full-scale charge current; it servos to 0.8V at full scale, with BAT-to-PROG current ratio internally set to 2500."
      },
      {
        "number": "3",
        "name": "CLPROG",
        "type": "output",
        "description": "VSYS current monitor output whose voltage equals 32 times the VIN-to-CLN differential, and charge current is reduced when it reaches 0.8V."
      },
      {
        "number": "4",
        "name": "CHGOFF",
        "type": "input",
        "description": "Battery charger disable input: tie to GND to enable the charger or to a voltage above 1.2V to disable it, and do not leave it unconnected."
      },
      {
        "number": "5",
        "name": "BSTOFF",
        "type": "input",
        "description": "Backup boost converter disable input: tie to GND to enable backup or to a voltage above 1.2V to disable it, and do not leave it unconnected."
      },
      {
        "number": "6",
        "name": "VIN",
        "type": "power_in",
        "description": "Input supply pin that can be driven directly when OVP is not used, otherwise an external N-channel FET is connected between the supply output VPWR and this pin."
      },
      {
        "number": "7",
        "name": "CLN",
        "type": "input",
        "description": "Negative terminal of the external input current-limit sense resistor between VIN and CLN, which regulates the sense drop to 25mV and does not limit system current if the drop exceeds 25mV."
      },
      {
        "number": "8",
        "name": "CHRG",
        "type": "output",
        "description": "Open-drain charge status output, typically pulled up to a reference voltage, that is pulled low during charging until charge current falls below C/8."
      },
      {
        "number": "9",
        "name": "FAULT",
        "type": "output",
        "description": "Open-drain fault status output, typically pulled up to a reference voltage, that is pulled low on a temperature fault or bad-battery fault during charging."
      },
      {
        "number": "10",
        "name": "RSTFB",
        "type": "input",
        "description": "High-impedance input to the reset comparator with a 0.74V falling threshold and 20mV hysteresis, using an external divider between VSYS, RSTFB and GND."
      },
      {
        "number": "11",
        "name": "RST",
        "type": "output",
        "description": "Open-drain reset output pulled to ground whenever RSTFB falls below 0.74V and becoming high impedance 232ms after RSTFB recovers."
      },
      {
        "number": "12",
        "name": "F2",
        "type": "input",
        "description": "Logic input selecting battery chemistry, where logic high selects Li-Ion and logic low selects LiFePO4, and it must not be left unconnected."
      },
      {
        "number": "13",
        "name": "F1",
        "type": "input",
        "description": "Logic input selecting one of four charge voltage settings for the chosen chemistry, and it must not be left unconnected."
      },
      {
        "number": "14",
        "name": "F0",
        "type": "input",
        "description": "Logic input selecting one of four charge voltage settings for the chosen chemistry, and it must not be left unconnected."
      },
      {
        "number": "15",
        "name": "IGATE",
        "type": "output",
        "description": "Gate drive from an internal charge pump for the external N-channel pass FETs, where the first FET (VPWR to VIN) is part of the optional OVP and the second FET (VIN to VSYS) is mandatory for backup disconnect."
      },
      {
        "number": "16",
        "name": "OVSNS",
        "type": "input",
        "description": "Overvoltage protection sense input that connects through a 6.2k resistor to the input connector and FET drain if OVP is used, or is shorted to VIN if not; IGATE is pulled to GND when it exceeds about 6V."
      },
      {
        "number": "17",
        "name": "NTC",
        "type": "passive",
        "description": "Thermistor monitoring input that uses a low-drift bias resistor from VIN and a thermistor to GND to pause charging when the battery is too hot or too cold, and should be grounded if NTC is not used."
      },
      {
        "number": "18",
        "name": "BSTFB",
        "type": "input",
        "description": "Feedback input for the backup boost regulator that servos to 0.8V during steady-state backup operation."
      },
      {
        "number": "19",
        "name": "PFI",
        "type": "input",
        "description": "High-impedance power-fail comparator input with a 1.19V falling threshold and 30mV hysteresis that sets the input voltage below which boost backup starts."
      },
      {
        "number": "20",
        "name": "PFO",
        "type": "output",
        "description": "Open-drain power-fail status output that is pulled to ground when PFI is below its falling threshold and becomes high impedance once PFI rises above the rising threshold."
      },
      {
        "number": "21",
        "name": "SW",
        "type": "passive",
        "description": "Switch node for the buck charger and boost backup converter, requiring a 1µH to 2.2µH inductor connected from SW to BAT."
      },
      {
        "number": "22",
        "name": "SW",
        "type": "passive",
        "description": "Switch node for the buck charger and boost backup converter, requiring a 1µH to 2.2µH inductor connected from SW to BAT."
      },
      {
        "number": "23",
        "name": "BAT",
        "type": "bidirectional",
        "description": "Single-cell Li-Ion or LiFePO4 battery connection that supplies VSYS through the boost converter in backup and is charged from VSYS through the buck charger; bypass with a low-ESR ceramic capacitor of at least 10µF to GND."
      },
      {
        "number": "24",
        "name": "VSYS",
        "type": "power_out",
        "description": "System voltage output that powers the external load from the input supply or the backup battery and charges the battery when input power is available; bypass with a low-ESR ceramic capacitor of at least 100µF to GND."
      },
      {
        "number": "25",
        "name": "GND",
        "type": "power_in",
        "description": "Exposed pad that must be soldered to the PCB to provide a low electrical and thermal impedance connection to ground."
      }
    ],
    "provenance": {
      "extractor": "extract_pins 0.3",
      "factory_chain": {
        "factory": "2.0.0",
        "extractor": "extract_pins 0.3",
        "primary_model": "claude-haiku-5-5",
        "primary_mode": "text",
        "consensus_model": "claude-sonnet-5-5",
        "consensus": "agreed",
        "guards": "pin_guards 0.1: passed",
        "guard_notes": [
          "extractor flagged: The top-view drawing text on page 2 is garbled, so pin numbers were taken from the Pin Functions sec; The datasheet does not state a pin type for PROG, NTC, and the SW pins; these were classified as pas; BAT both sources power to VSYS in backup and sinks charge current, so it was classed as bidirectiona"
        ],
        "pages_sent": 10,
        "cost_usd": 0.0893,
        "at": "2026-10-18T06:45:05"
      },
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        "pages": 26,
        "sha256": "957228362ca0845d",
        "source_tier": "lcsc"
      },
      "cad": "KiCad official (CC-BY-SA 4.0)",
      "pins": {
        "total": 25,
        "described": 25,
        "cites_pages": true,
        "refuses_to_fabricate": true
      }
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}