A4988SETTR-T

{
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  "type": "component",
  "slug": "a4988settr-t",
  "title": "A4988SETTR-T",
  "brief": "Allegro MicroSystems LLC Stepper Motor Driver, WQFN-28-EP(5x5). Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.",
  "version": "0.1.0",
  "license": "CC-BY-SA-4.0",
  "tags": [
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    "motor driver ics",
    "a4988settr-t",
    "factory-2.0.0",
    "extractor-text"
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  "component": {
    "mpn": "A4988SETTR-T",
    "manufacturer": "Allegro MicroSystems LLC",
    "package": "WQFN-28-EP(5x5)",
    "pin_count": 29,
    "category": "Motor Driver ICs",
    "subcategory": "Stepper Motor Driver",
    "datasheet": "https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8586175153008463872",
    "parts": {
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      "lbr": "a4988settr-t.lbr"
    },
    "distributor_links": {
      "lcsc": "C38437",
      "digikey": "620-1343-2-ND",
      "mouser": "250-A4988SETTR-T"
    },
    "distributor_check": {
      "checked_at": "2026-10-18T01:52:56Z",
      "source": "Component Ocean /api/assign-pns",
      "digikey": {
        "pn": "620-1343-2-ND",
        "status": "found",
        "lifecycle": "Active"
      },
      "mouser": {
        "pn": "250-A4988SETTR-T",
        "status": "found"
      }
    },
    "pins": [
      {
        "number": "1",
        "name": "OUT2B",
        "type": "output",
        "description": "DMOS Full Bridge 2 Output B."
      },
      {
        "number": "2",
        "name": "ENABLE",
        "type": "input",
        "description": "Logic input: when set high all FET outputs are disabled, and when set low the internal control enables the outputs as required; STEP, DIR and MSx remain active regardless of its state."
      },
      {
        "number": "3",
        "name": "GND",
        "type": "power_in",
        "description": "Ground; internally fused for thermal dissipation and must be tied together externally to the PAD ground plane under the device."
      },
      {
        "number": "4",
        "name": "CP1",
        "type": "passive",
        "description": "Charge pump capacitor terminal; a 0.1 µF ceramic capacitor is connected between CP1 and CP2."
      },
      {
        "number": "5",
        "name": "CP2",
        "type": "passive",
        "description": "Charge pump capacitor terminal; a 0.1 µF ceramic capacitor is connected between CP1 and CP2."
      },
      {
        "number": "6",
        "name": "VCP",
        "type": "passive",
        "description": "Reservoir capacitor terminal; a 0.1 µF ceramic capacitor is required between VCP and VBB, and an undervoltage on VCP disables the FET outputs."
      },
      {
        "number": "7",
        "name": "NC",
        "type": "unconnected",
        "description": "No connection."
      },
      {
        "number": "8",
        "name": "VREG",
        "type": "passive",
        "description": "Regulator decoupling terminal; nominal output 7 V, to be decoupled with a 0.22 µF ceramic capacitor to ground."
      },
      {
        "number": "9",
        "name": "MS1",
        "type": "input",
        "description": "Logic input for microstep select; MS1 has a 100 kΩ pull-down resistance."
      },
      {
        "number": "10",
        "name": "MS2",
        "type": "input",
        "description": "Logic input for microstep select; MS2 has a 50 kΩ pull-down resistance."
      },
      {
        "number": "11",
        "name": "MS3",
        "type": "input",
        "description": "Logic input for microstep select; MS3 has a 100 kΩ pull-down resistance."
      },
      {
        "number": "12",
        "name": "RESET",
        "type": "input",
        "description": "Logic input that sets the translator to the predefined Home state and turns off all FET outputs; STEP inputs are ignored while RESET is low."
      },
      {
        "number": "13",
        "name": "ROSC",
        "type": "passive",
        "description": "Timing set terminal: tied to VDD or to ground gives a 30 µs fixed off-time, and a resistor to ground sets tOFF ≈ ROSC/825 µs (ROSC in kΩ, tOFF in µs)."
      },
      {
        "number": "14",
        "name": "SLEEP",
        "type": "input",
        "description": "Logic input; a logic low puts the device into Sleep mode, disabling the output FETs, current regulator and charge pump, and a 1 ms delay is needed before a STEP command after leaving Sleep."
      },
      {
        "number": "15",
        "name": "VDD",
        "type": "power_in",
        "description": "Logic supply; operating range 3.0 to 5.5 V, with absolute maximum rating -0.3 to 5.5 V."
      },
      {
        "number": "16",
        "name": "STEP",
        "type": "input",
        "description": "Logic input; each low-to-high transition advances the motor one microstep."
      },
      {
        "number": "17",
        "name": "REF",
        "type": "input",
        "description": "Gm reference voltage input; VREF operating range is 0 to 4 V and sets the maximum current trip level via ITripMAX = VREF/(8×RS)."
      },
      {
        "number": "18",
        "name": "GND",
        "type": "power_in",
        "description": "Ground; internally fused for thermal dissipation and must be tied together externally to the PAD ground plane under the device."
      },
      {
        "number": "19",
        "name": "DIR",
        "type": "input",
        "description": "Logic input that sets the direction of rotation; changes take effect only on the next STEP rising edge."
      },
      {
        "number": "20",
        "name": "NC",
        "type": "unconnected",
        "description": "No connection."
      },
      {
        "number": "21",
        "name": "OUT1B",
        "type": "output",
        "description": "DMOS Full Bridge 1 Output B."
      },
      {
        "number": "22",
        "name": "VBB1",
        "type": "power_in",
        "description": "Load supply for Bridge 1; operating range 8 to 35 V, with absolute maximum rating 35 V."
      },
      {
        "number": "23",
        "name": "SENSE1",
        "type": "passive",
        "description": "Sense resistor terminal for Bridge 1; the sense voltage must not exceed the 0.5 V maximum rating."
      },
      {
        "number": "24",
        "name": "OUT1A",
        "type": "output",
        "description": "DMOS Full Bridge 1 Output A."
      },
      {
        "number": "25",
        "name": "NC",
        "type": "unconnected",
        "description": "No connection."
      },
      {
        "number": "26",
        "name": "OUT2A",
        "type": "output",
        "description": "DMOS Full Bridge 2 Output A."
      },
      {
        "number": "27",
        "name": "SENSE2",
        "type": "passive",
        "description": "Sense resistor terminal for Bridge 2; the sense voltage must not exceed the 0.5 V maximum rating."
      },
      {
        "number": "28",
        "name": "VBB2",
        "type": "power_in",
        "description": "Load supply for Bridge 2; operating range 8 to 35 V, with absolute maximum rating 35 V."
      },
      {
        "number": "29",
        "name": "PAD",
        "type": "passive",
        "description": "Exposed pad (from the footprint; not named in the datasheet pin table)."
      }
    ],
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        "guards": "pin_guards 0.1: passed",
        "guard_notes": [
          "exposed pad 29 added from the footprint",
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        "at": "2026-10-18T01:51:14"
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          "name": "Output On Resistance, Source Driver",
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          "unit": "mΩ",
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          "name": "Output On Resistance, Sink Driver",
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          "conditions": "fPWM < 50 kHz",
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          "conditions": "fPWM < 50 kHz",
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          "conditions": "Outputs off",
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        },
        {
          "name": "Logic Input Current (high)",
          "symbol": "IIN(1)",
          "kind": "electrical",
          "unit": "µA",
          "min": -20,
          "typ": 1,
          "max": 20,
          "conditions": "VIN = VDD×0.7",
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        {
          "name": "Logic Input Current (low)",
          "symbol": "IIN(0)",
          "kind": "electrical",
          "unit": "µA",
          "min": -20,
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          "conditions": "VIN = VDD×0.3",
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        {
          "name": "Logic Input Hysteresis",
          "symbol": "VHYS(IN)",
          "kind": "electrical",
          "unit": "%",
          "min": 5,
          "typ": 11,
          "max": 19,
          "conditions": "As a % of VDD",
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        {
          "name": "Blank Time",
          "symbol": "tBLANK",
          "kind": "timing",
          "unit": "μs",
          "min": 0.7,
          "typ": 1,
          "max": 1.3,
          "conditions": "",
          "source_page": 4,
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        {
          "name": "Fixed Off-Time",
          "symbol": "tOFF",
          "kind": "timing",
          "unit": "μs",
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          "max": 40,
          "conditions": "OSC = VDD or GND",
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          "conditions": "ROSC = 25 kΩ",
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          "name": "VDD Undervoltage Lockout",
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          "name": "Output Current",
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          "name": "Logic Input Voltage (absolute maximum)",
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          "name": "Maximum Junction Temperature",
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