LT3991EMSE-5#PBF

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  "slug": "lt3991emse-5-pbf",
  "title": "LT3991EMSE-5#PBF",
  "brief": "Analog Devices DC-DC Converters, MSOP-10-EP. Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.",
  "version": "0.1.0",
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    "mpn": "LT3991EMSE-5#PBF",
    "manufacturer": "Analog Devices",
    "package": "MSOP-10-EP",
    "pin_count": 11,
    "category": "Power Management ICs",
    "subcategory": "DC-DC Converters",
    "datasheet": "https://www.analog.com/media/en/technical-documentation/data-sheets/3991fa.pdf",
    "parts": {
      "symbol": "lt3991emse-5-pbf.kicad_sym",
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      "lbr": "lt3991emse-5-pbf.lbr"
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    "distributor_links": {
      "lcsc": "C671881",
      "digikey": "LT3991EMSE-5#PBF-ND",
      "mouser": "584-LT3991EMSE-5#PBF"
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    "pins": [
      {
        "number": "1",
        "name": "BD",
        "type": "passive",
        "description": "Connects to the anode of the boost Schottky diode and is normally connected to the output."
      },
      {
        "number": "2",
        "name": "BOOST",
        "type": "power_in",
        "description": "Provides a drive voltage higher than the input voltage to the internal NPN power switch, supplied through an external boost capacitor."
      },
      {
        "number": "3",
        "name": "SW",
        "type": "output",
        "description": "Output of the internal power switch; connects to the inductor, catch diode and boost capacitor."
      },
      {
        "number": "4",
        "name": "VIN",
        "type": "power_in",
        "description": "Supplies current to the internal circuitry and power switch over the 4.3V to 55V input range and must be locally bypassed."
      },
      {
        "number": "5",
        "name": "EN",
        "type": "input",
        "description": "Shutdown when low and active when high, with 1.005V rising and 0.975V falling thresholds; the threshold is only accurate when VIN is above 4.3V."
      },
      {
        "number": "6",
        "name": "VOUT",
        "type": "input",
        "description": "On the LT3991-5 this pin regulates the output to 5V and connects to the internal 10MΩ feedback divider that programs the fixed output voltage."
      },
      {
        "number": "7",
        "name": "SS",
        "type": "passive",
        "description": "A capacitor and series resistor to ground slowly ramp the peak current limit on start-up; the typical soft-start resistor is 100k, and floating the pin disables soft-start."
      },
      {
        "number": "8",
        "name": "RT",
        "type": "passive",
        "description": "A resistor tied between RT and ground sets the switching frequency."
      },
      {
        "number": "9",
        "name": "PG",
        "type": "output",
        "description": "Open-drain power good output that remains low until the FB pin is within 9% of the final regulation voltage and is valid when the part is enabled and VIN is above 4.3V."
      },
      {
        "number": "10",
        "name": "SYNC",
        "type": "input",
        "description": "External clock synchronization input; grounding it gives low-ripple Burst Mode operation at low output loads, while a clock source synchronizes the switching frequency with pulse-skipping at low loads."
      },
      {
        "number": "11",
        "name": "GND",
        "type": "power_in",
        "description": "Ground; the exposed pad must be soldered to the PCB."
      }
    ],
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        "at": "2026-10-28T15:45:15"
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      "datasheet": {
        "url": "https://www.analog.com/media/en/technical-documentation/data-sheets/3991fa.pdf",
        "pages": 24,
        "sha256": "05394db5ad4d382a",
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      "cad": "KiCad official (CC-BY-SA 4.0)",
      "pins": {
        "total": 11,
        "described": 11,
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          "name": "Switch Leakage Current",
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          "kind": "electrical",
          "unit": "μA",
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          "kind": "electrical",
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          "min": 0.95,
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          "name": "LT3991-X PG Threshold Offset from VOUT",
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          "kind": "electrical",
          "unit": "%",
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          "typ": 0.02,
          "max": 1,
          "conditions": "VPG = 3V",
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          "name": "PG Sink Current",
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          "kind": "electrical",
          "unit": "μA",
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          "max": 570,
          "conditions": "VPG = 0.4V, l: full operating temperature range",
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          "name": "SYNC Threshold",
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          "min": 0.6,
          "typ": 0.8,
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          "typ": 0.1,
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          "name": "SS Source Current",
          "symbol": "",
          "kind": "electrical",
          "unit": "μA",
          "min": 0.6,
          "typ": 1,
          "max": 1.6,
          "conditions": "VSS = 1V",
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          "name": "BOOST Pin Above SW Pin",
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          "name": "FB, VOUT, RT, SYNC, SS Voltage",
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          "name": "Boost Diode Current",
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          "name": "Operating Junction Temperature Range (LT3991E)",
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          "name": "Lead Temperature (Soldering, 10 sec) (MSE Only)",
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