LM27403SQ

{
  "slug": "lm27403sq",
  "version": "0.1.0",
  "type": "component",
  "description": "Texas Instruments DC-DC Controllers, QFN-24-EP(4x4). Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.",
  "tags": [
    "component",
    "power management ics",
    "lm27403sq",
    "factory-2.0.0",
    "extractor-text"
  ],
  "dependencies": {},
  "hero": {
    "type": "image",
    "path": "docs/hero.png"
  },
  "files": [
    "page.json",
    "README.md",
    "lm27403sq.kicad_sym",
    "lm27403sq.kicad_mod",
    "lm27403sq.glb",
    "lm27403sq.step",
    "lm27403sq.lbr",
    "docs/hero.png",
    "docs/lm27403sq-datasheet.pdf",
    "viewers/symbol.html",
    "viewers/footprint.html",
    "lm27403sq-hero.glb",
    "lm27403sq-hero.overlay.json",
    "lm27403sq-etched.glb"
  ],
  "component": {
    "mpn": "LM27403SQ",
    "manufacturer": "Texas Instruments",
    "package": "QFN-24-EP(4x4)",
    "pin_count": 25,
    "category": "Power Management ICs",
    "subcategory": "DC-DC Controllers",
    "datasheet": "https://www.ti.com/lit/ds/symlink/lm27403sq.pdf",
    "parts": {
      "symbol": "lm27403sq.kicad_sym",
      "footprint": "lm27403sq.kicad_mod",
      "model_3d": "lm27403sq-hero.glb",
      "model_3d_plain": "lm27403sq-etched.glb",
      "model_3d_step": "lm27403sq-etched.step",
      "model_3d_step_plain": "lm27403sq.step",
      "lbr": "lm27403sq.lbr"
    },
    "distributor_links": {
      "lcsc": "C2650249"
    },
    "distributor_check": {
      "checked_at": "2026-10-30T16:11:51Z",
      "source": "Component Ocean /api/assign-pns",
      "digikey": {
        "pn": null,
        "status": "no match"
      },
      "mouser": {
        "pn": null,
        "status": "no match"
      }
    },
    "pins": [
      {
        "number": "1",
        "name": "SS/TRACK",
        "type": "bidirectional",
        "description": "Soft-start or tracking input: a capacitor to GND sets the startup rate, a 3-µA source charges it until the reference reaches 0.6 V, and it can be driven externally from 0 V to VDD for tracking."
      },
      {
        "number": "2",
        "name": "RS",
        "type": "input",
        "description": "Negative remote sense input that removes the ground drop between GND and the local load ground, with RS limited to -0.1 V to 0.1 V and tied to GND at the IC if unused."
      },
      {
        "number": "3",
        "name": "FB",
        "type": "input",
        "description": "Voltage-mode error amplifier inverting input that sets the output voltage, held at 0.6 V ±1% in closed-loop regulation."
      },
      {
        "number": "4",
        "name": "COMP",
        "type": "output",
        "description": "Error amplifier output that is connected to FB through a compensation network to ensure loop stability."
      },
      {
        "number": "5",
        "name": "FADJ",
        "type": "input",
        "description": "Frequency adjust input whose connected resistor to GND sets the switching frequency, programmable from 200 kHz to 1.2 MHz."
      },
      {
        "number": "6",
        "name": "SYNC",
        "type": "input",
        "description": "Synchronization input for PLL locking to an external clock, limited to 0 V to 5.5 V, defaulting to the FADJ frequency when no clock is present and to be tied to GND if unused."
      },
      {
        "number": "7",
        "name": "UVLO/EN",
        "type": "input",
        "description": "Precision UVLO/enable input with a 1.15-V rising enable threshold, 0.985-V falling threshold, 165-mV voltage hysteresis, and a pin range of 0 V to min(VIN, 5.5 V)."
      },
      {
        "number": "8",
        "name": "OTP",
        "type": "input",
        "description": "Overtemperature protection setpoint pin where a resistor and 0.1-µF capacitor to GND set the OTP threshold from the remote thermal diode, and it is connected to GND if system OTP is not required."
      },
      {
        "number": "9",
        "name": "D+",
        "type": "input",
        "description": "External temperature sense input for a 2N3904-type NPN remote thermal diode (base and collector shorted) used to compensate inductor DCR drift and provide system thermal shutdown."
      },
      {
        "number": "10",
        "name": "D-",
        "type": "input",
        "description": "Return path for the external NPN thermal diode, to be routed as a differential pair with D+ and connected to GND."
      },
      {
        "number": "11",
        "name": "PGOOD",
        "type": "output",
        "description": "Open-drain power-good output that goes low during fault or unregulated conditions, requires an external pullup, includes a 20-µs deglitch filter, and must not exceed 5.5 V."
      },
      {
        "number": "12",
        "name": "VIN",
        "type": "power_in",
        "description": "Input voltage rail operating from 3.0 V to 20 V that provides feedforward and internal bias generation, to be decoupled locally with a 1-µF ceramic capacitor."
      },
      {
        "number": "13",
        "name": "GND",
        "type": "power_in",
        "description": "Common ground for power and signal return, including low-side gate return, soft-start capacitor, OTP resistor, and frequency adjust resistor."
      },
      {
        "number": "14",
        "name": "VDD",
        "type": "power_out",
        "description": "Subregulated 4.7-V bias supply rail (VDD range 2.6 V to 5.5 V) for internal and gate drive circuits, to be decoupled with a 10-µF ceramic capacitor and not used to drive auxiliary loads."
      },
      {
        "number": "15",
        "name": "LG",
        "type": "output",
        "description": "Low-side MOSFET gate drive output that connects to the low-side N-FET gate."
      },
      {
        "number": "16",
        "name": "SW",
        "type": "power_out",
        "description": "Power stage switch-node connection that also serves as the high-side N-FET gate driver return, tolerating negative spikes to -10 V and positive spikes to 30 V for up to 10 ns."
      },
      {
        "number": "17",
        "name": "HG",
        "type": "output",
        "description": "High-side MOSFET gate drive output that connects to the high-side N-FET gate."
      },
      {
        "number": "18",
        "name": "CBOOT",
        "type": "power_in",
        "description": "High-side bootstrap connection supplying the high-side N-FET gate driver, with a 100-nF ceramic capacitor between CBOOT and SW and spikes up to 35 V tolerated for 10 ns."
      },
      {
        "number": "19",
        "name": "NC",
        "type": "unconnected",
        "description": "No connection; the datasheet says to connect this pin directly to GND."
      },
      {
        "number": "20",
        "name": "NC",
        "type": "unconnected",
        "description": "No connection; the datasheet says to connect this pin directly to GND."
      },
      {
        "number": "21",
        "name": "NC",
        "type": "unconnected",
        "description": "No connection; the datasheet says to connect this pin directly to GND."
      },
      {
        "number": "22",
        "name": "NC",
        "type": "unconnected",
        "description": "No connection; the datasheet says to connect this pin directly to GND."
      },
      {
        "number": "23",
        "name": "CS+",
        "type": "input",
        "description": "Noninverting input to the current-sense comparator for DCR-based overcurrent sensing, with CS+ to CS- limited to ±1 V."
      },
      {
        "number": "24",
        "name": "CS-",
        "type": "input",
        "description": "Inverting input to the current-sense comparator, with 9.9 µA of nominal offset current at room temperature used to adjust the current-limit setpoint."
      },
      {
        "number": "25",
        "name": "EP",
        "type": "passive",
        "description": "Exposed pad (from the footprint; not named in the datasheet pin table)."
      }
    ],
    "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 datasheet lists these as NC and says to connect them directly to GND. I used KiCad 'unconnected'; The exposed pad is labelled 'EP' in the datasheet, not given a numeric pin. Its type is set to power; The datasheet marks SW and VDD as type P without a direction. I assigned power_out, since SW is the ",
          "exposed pad 25 added from the footprint",
          "dropped thermal pad ['EP'] absent from footprint",
          "1/25 pins cited to the wrong page (name found elsewhere): ['21:NC@p4']"
        ],
        "pages_sent": 8,
        "cost_usd": 0.0675,
        "at": "2026-10-30T16:11:33"
      },
      "datasheet": {
        "url": "https://www.ti.com/lit/ds/symlink/lm27403sq.pdf",
        "pages": 56,
        "sha256": "b9d9b331b0096516",
        "source_tier": "mfr"
      },
      "cad": "KiCad official (CC-BY-SA 4.0)",
      "pins": {
        "total": 25,
        "described": 25,
        "cites_pages": true,
        "refuses_to_fabricate": true
      }
    },
    "viewers": {
      "symbol": "viewers/symbol.html",
      "footprint": "viewers/footprint.html"
    },
    "models_3d": [
      {
        "file": "lm27403sq.step",
        "role": "plain",
        "up": "Z",
        "units": "mm",
        "origin": "footprint origin = pad-pattern centre",
        "seat": "z = 0",
        "extents_mm": [
          4.0,
          4.0,
          0.77
        ],
        "zmin_mm": 0.0,
        "centre_offset_mm": 0.0,
        "footprint_binding": "identity",
        "sha256": "096fc110543e6d324c5120c2d38e3dca87a389da9b6fac234f1fe40856295ef4",
        "checked": "2026-10-30",
        "checked_by": "factory/step_pose.py (Z-up, origin, seat, binding)"
      },
      {
        "file": "lm27403sq-etched.step",
        "role": "eda",
        "up": "Z",
        "units": "mm",
        "origin": "footprint origin = pad-pattern centre",
        "seat": "z = 0",
        "extents_mm": [
          4.0,
          4.0,
          0.77
        ],
        "zmin_mm": 0.0,
        "centre_offset_mm": 0.0,
        "footprint_binding": "identity",
        "sha256": "fbc345db935ccb62078e9b3f5115ff476d5084c13d0fed395ec8f1cd972a587f",
        "checked": "2026-10-30",
        "checked_by": "factory/step_pose.py (Z-up, origin, seat, binding)"
      }
    ],
    "package_dims": {
      "package_code": "RTW0024A (WQFN-24)",
      "source_page": 53,
      "D": {
        "nom_mm": 4.0,
        "range_mm": [
          3.9,
          4.1
        ]
      },
      "E1": {
        "nom_mm": 4.0,
        "range_mm": [
          3.9,
          4.1
        ]
      },
      "e": {
        "nom_mm": 0.5,
        "range_mm": [
          null,
          null
        ]
      },
      "A": {
        "nom_mm": 0.8,
        "range_mm": [
          null,
          0.8
        ]
      },
      "source": "datasheet package drawing, every number found on its page (extract_pins --task dims)",
      "model_check": {
        "file": "lm27403sq.step",
        "verdict": "PASS",
        "reasons": [
          "height within the datasheet's package drawing"
        ],
        "by": "factory/package_fit.py"
      }
    }
  }
}