TX4138

{
  "schema_version": 1,
  "type": "component",
  "slug": "tx4138",
  "title": "TX4138",
  "brief": "XDS DC-DC Converters, SOIC-8-EP. Pinout extracted from the datasheet, KiCad symbol/footprint/3D.",
  "version": "0.2.0",
  "license": "CC-BY-SA-4.0",
  "tags": [
    "component",
    "pmic",
    "tx4138"
  ],
  "component": {
    "mpn": "TX4138",
    "manufacturer": "XDS",
    "package": "SOIC-8-EP",
    "pin_count": 9,
    "category": "PMIC",
    "subcategory": "DC-DC Converters",
    "datasheet": "https://datasheet.lcsc.com/datasheet/pdf/d024c4d04581d564b9ef26614fc64acf.pdf",
    "parts": {
      "symbol": "tx4138.kicad_sym",
      "footprint": "tx4138.kicad_mod",
      "model_3d": "tx4138-etched.glb",
      "model_3d_plain": "tx4138.glb",
      "model_3d_step": "tx4138-etched.step",
      "model_3d_step_plain": "tx4138.step",
      "lbr": "tx4138.lbr"
    },
    "distributor_links": {
      "lcsc": "C329267"
    },
    "pins": [
      {
        "number": "1",
        "name": "SW",
        "type": "output",
        "description": "Switch node output. Source of the internal high-side power MOSFET; connect this pin to the switching end of the inductor and to the cathode of the external freewheeling Schottky diode. Absolute maximum: -0.3V to VIN + 0.3V."
      },
      {
        "number": "2",
        "name": "ILIM",
        "type": "power_in",
        "description": "Programmable maximum peak current pin. Power current flows into the chip through an external accurate sense resistor connected between ILIM and VIN; the sense resistor value (~15-30mΩ) sets the peak current limit (30mΩ for 2A, 20mΩ for 3A, 15mΩ for 4A). Internally tied to the power MOSFET, so heat dissipation on this pin matters. Absolute maximum: 62V."
      },
      {
        "number": "3",
        "name": "VIN",
        "type": "power_in",
        "description": "Supply voltage input, 4.5V to 60V unregulated. Also the drain of the internal high-side power MOSFET and power supply for the whole chip. A local input capacitor (CIN) placed as close to the IC as possible is required to prevent large voltage spikes. Absolute maximum: 62V."
      },
      {
        "number": "4",
        "name": "GND",
        "type": "power_in",
        "description": "Ground return and voltage reference for the regulated output. Should be routed carefully outside the D1-to-CIN high-current ground path to prevent switching current spikes from injecting noise into the part."
      },
      {
        "number": "5",
        "name": "FB",
        "type": "input",
        "description": "Feedback input to the error amplifier. An external resistor divider from VOUT to GND, tapped to FB, sets the output voltage; reference is 0.805V (typ, 0.785-0.825V). When FB falls below 250mV a frequency-fold-back comparator reduces oscillator frequency to prevent short-circuit current-limit runaway. Bias current ~10nA. Absolute maximum: -0.3V to +6.5V."
      },
      {
        "number": "6",
        "name": "EN",
        "type": "input",
        "description": "Enable input. Drive low to disable (turn off) the chip; leave floating (or drive high) to enable. Absolute maximum: -0.3V to +6.5V."
      },
      {
        "number": "7",
        "name": "POK",
        "type": "output",
        "description": "Power-good open-drain output. Pulled low while FB is less than 90% of the 0.8V reference; goes high-Z when output is in regulation. Requires an external pull-up (e.g. 10kΩ) to a system rail up to 45V; can also drive the enable pin of a downstream converter. Tie to GND or leave floating if unused. Absolute maximum: 0V to 45V."
      },
      {
        "number": "8",
        "name": "BS",
        "type": "passive",
        "description": "Bootstrap capacitor pin. Provides the positive supply rail for the high-side MOSFET gate driver (VBST - VSW = 6V typ). Connect a 100nF ceramic capacitor and a series ~5-10Ω resistor between BS and SW. Absolute maximum: VSW + 6.0V."
      },
      {
        "number": "9",
        "name": "ILIM (EP)",
        "type": "power_in",
        "description": "Exposed thermal pad, internally connected to the ILIM node (same net as pin 2). Provides the primary heat-dissipation path for the internal power MOSFET and must be soldered to a copper pour that also carries the ILIM/sense-resistor current back to VIN."
      }
    ],
    "provenance": {
      "extractor": "ds2sf",
      "datasheet": {
        "url": "https://datasheet.lcsc.com/datasheet/pdf/d024c4d04581d564b9ef26614fc64acf.pdf",
        "pages": 7,
        "sha256": "cd9a50cd55184667",
        "source_tier": "lcsc"
      },
      "cad": "KiCad official (CC-BY-SA 4.0)",
      "pins": {
        "total": 9,
        "described": 9,
        "cites_pages": true,
        "refuses_to_fabricate": true
      }
    },
    "viewers": {
      "symbol": "viewers/symbol.html",
      "footprint": "viewers/footprint.html"
    },
    "pin1": {
      "pad": "1",
      "at": [
        -2.475,
        -1.905
      ],
      "corner": "top-left",
      "source": "silk-marker",
      "derived_from": "SOIC-8-1EP_3.9x4.9mm_P1.27mm_EP2.29x3mm@sha256:a7971720bdda0353",
      "mark": "drawn"
    },
    "models_3d": [
      {
        "file": "tx4138.step",
        "role": "plain",
        "up": "Z",
        "units": "mm",
        "origin": "footprint origin = pad-pattern centre",
        "seat": "z = 0",
        "extents_mm": [
          6,
          4.9,
          1.55
        ],
        "zmin_mm": 0,
        "centre_offset_mm": 0,
        "footprint_binding": "identity",
        "sha256": "2d6f7e774e8143e3320cbd59eb5be9f3b7864614644e3b072006e1eb05fb7fa6",
        "checked": "2026-10-07",
        "checked_by": "factory/step_pose.py (Z-up, origin, seat, binding)"
      },
      {
        "file": "tx4138-etched.step",
        "role": "eda",
        "up": "Z",
        "units": "mm",
        "origin": "footprint origin = pad-pattern centre",
        "seat": "z = 0",
        "extents_mm": [
          6,
          4.9,
          1.55
        ],
        "zmin_mm": 0,
        "centre_offset_mm": 0,
        "footprint_binding": "identity",
        "sha256": "b3d499a5f3291afa83808762ef31ac0bb1b456bf0fe03305d19d6d0f5af36246",
        "checked": "2026-10-07",
        "checked_by": "factory/step_pose.py (Z-up, origin, seat, binding)"
      }
    ]
  },
  "metadata": {
    "specs": {
      "Manufacturer": "XDS",
      "Package": "SOIC-8-EP",
      "Category": "PMIC",
      "Pins": "9"
    }
  },
  "sections": [
    "hero",
    "viewers",
    "readme",
    "breadcrumbs",
    "info"
  ],
  "discovery_triggers": [
    "tx4138"
  ],
  "discovery_pitch": "TX4138 (XDS) component page with datasheet-verified CAD.",
  "author": {
    "name": "Ray"
  },
  "dependencies": {},
  "hero": {
    "type": "image",
    "path": "docs/hero.png"
  },
  "files": [
    "page.json",
    "README.md",
    "tx4138.kicad_sym",
    "tx4138.kicad_mod",
    "tx4138.glb",
    "tx4138.step",
    "tx4138-etched.step",
    "tx4138.lbr",
    "docs/hero.png",
    "docs/tx4138-datasheet.pdf",
    "viewers/symbol.html",
    "viewers/footprint.html"
  ],
  "variants": [
    {
      "mpn": "TX4138",
      "kind": "packaging"
    }
  ],
  "updated_at": "2026-09-25T13:16:25.705Z"
}