component
L4981BD
Public Made by Adomby adom
STMicroelectronics AC-DC Controllers & Regulators, SOIC-20-300mil. Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.
main
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"description": "STMicroelectronics AC-DC Controllers & Regulators, SOIC-20-300mil. Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.",
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"component": {
"mpn": "L4981BD",
"manufacturer": "STMicroelectronics",
"package": "SOIC-20-300mil",
"pin_count": 20,
"category": "Power Management ICs",
"subcategory": "AC-DC Controllers & Regulators",
"datasheet": "https://www.st.com/resource/en/datasheet/l4981bd.pdf",
"parts": {
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"distributor_links": {
"lcsc": "C2970992",
"digikey": "497-5338-5-ND",
"mouser": "511-L4981BD"
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"distributor_check": {
"checked_at": "2026-11-02T17:07:36Z",
"source": "Component Ocean /api/assign-pns",
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"pn": "497-5338-5-ND",
"status": "found"
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},
"pins": [
{
"number": "1",
"name": "P-GND",
"type": "power_in",
"description": "Power ground return for the gate driver and power stage, kept separate from signal ground S-GND (pin 10)."
},
{
"number": "2",
"name": "IPK",
"type": "input",
"description": "Peak current limit input for the L4981B, set by two external resistors between the sense resistor, pin 2 and the reference voltage; pin 2 is limited to -0.3 to 5.5 V (-2 V for 1 µs)."
},
{
"number": "3",
"name": "OVP",
"type": "input",
"description": "Overvoltage protection comparator input, compared against an internal 5.1 V (typ) reference via a divider from the boost output."
},
{
"number": "4",
"name": "IAC",
"type": "input",
"description": "AC current input carrying a current proportional to the rectified mains voltage, rated at 5 mA maximum."
},
{
"number": "5",
"name": "CA-OUT",
"type": "output",
"description": "Current amplifier output; an external RC network sets the current loop gain."
},
{
"number": "6",
"name": "LFF",
"type": "input",
"description": "Load feedforward input, best controlled between 1.5 V and 5.3 V; connect to VREF (pin 11) if unused."
},
{
"number": "7",
"name": "VRMS",
"type": "input",
"description": "Input for the proportional RMS line voltage, best controlled between 1.5 V and 5.5 V; connect to VREF (pin 11) if unused."
},
{
"number": "8",
"name": "MULT-OUT",
"type": "input",
"description": "Multiplier output shared with the current amplifier input; a high-impedance node that must not be taken below -0.5 V."
},
{
"number": "9",
"name": "ISENSE",
"type": "input",
"description": "Current amplifier inverting input that must not be driven below -0.5 V."
},
{
"number": "10",
"name": "S-GND",
"type": "power_in",
"description": "Signal ground reference for the control circuitry, separate from power ground P-GND (pin 1)."
},
{
"number": "11",
"name": "VREF",
"type": "power_out",
"description": "Precise ±2% reference output of 5.1 V (typ) that is internally current limited and can deliver up to 10 mA."
},
{
"number": "12",
"name": "SS",
"type": "passive",
"description": "Soft start capacitor pin; an internal 100 µA (typ) source charges the external capacitor, which is discharged during overvoltage and UVLO conditions."
},
{
"number": "13",
"name": "VA-OUT",
"type": "output",
"description": "Error amplifier output for which an RC network sets the voltage loop gain; the absolute maximum is 8.5 V."
},
{
"number": "14",
"name": "VFEED",
"type": "input",
"description": "Voltage error amplifier inverting input, fed through a divider from the boost output voltage."
},
{
"number": "15",
"name": "P-UVLO",
"type": "input",
"description": "Programmable undervoltage lockout threshold input, set by a divider between VCC and GND (for example 220K to VCC and 33K to GND gives about 12 V turn-on)."
},
{
"number": "16",
"name": "FREQ-MOD",
"type": "bidirectional",
"description": "On the L4981B this is the frequency modulation current input, with a resistor to the rectified line; the L4981A uses it as a CMOS-compatible SYNC input/output, and the absolute maximum is 7 V."
},
{
"number": "17",
"name": "ROSC",
"type": "passive",
"description": "An external resistor to ground sets the constant charging current of COSC; the pin voltage is rated -0.3 to 3 V."
},
{
"number": "18",
"name": "COSC",
"type": "passive",
"description": "An external capacitor to GND sets the switching frequency; the input sink current is rated at 15 mA."
},
{
"number": "19",
"name": "VCC",
"type": "power_in",
"description": "Supply input, rated at 19.5 V maximum operating supply voltage with a self-limiting zener (20 to 30 V) and an absolute maximum of 50 mA ICC."
},
{
"number": "20",
"name": "GDRV",
"type": "output",
"description": "Gate driver output using a bipolar and DMOS totem pole stage that can deliver peak current in excess of 1 A to drive a MOSFET or IGBT, with a peak sink of 2 A and a source of 1.5 A."
}
],
"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 gives SO20 (not 'SOIC-20-300mil') as the SO20 package for ordering number L4981XD, and"
],
"pages_sent": 16,
"cost_usd": 0.0245,
"at": "2026-11-02T17:07:26"
},
"datasheet": {
"url": "https://www.st.com/resource/en/datasheet/l4981bd.pdf",
"pages": 16,
"sha256": "607996fde19865e3",
"source_tier": "mfr"
},
"cad": "KiCad official (CC-BY-SA 4.0)",
"pins": {
"total": 20,
"described": 20,
"cites_pages": true,
"refuses_to_fabricate": true
}
},
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