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um1550s-18

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by Ray

Union Semiconductor Voltage Regulators - Linear, Low Drop Out (LDO) Regulators, SOT-23-3. Datasheet-verified pinout, KiCad symbol/footprint/3D.

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README

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UM1550S-18

Union Semiconductor · Voltage Regulators - Linear, Low Drop Out (LDO) Regulators · SOT-23-3

UM1550S-18 from Union Semiconductor, in a SOT-23-3. Pinout and pin descriptions extracted from the manufacturer datasheet by ds2sf; symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin Name Type Function
1 GND power_in Ground reference for the regulator. Connect to system ground with a low-impedance path.
2 VOUT power_out Regulated 1.8 V output (UM1550S-18 option). Delivers up to 250 mA. Requires a 1 µF output capacitor to ground for stability.
3 VIN power_in Supply input. Accepts 1.8 V to 8 V (absolute max 10 V). Bypass with a 1 µF capacitor to GND close to the pin.

Key specifications

Parameter Value
Manufacturer Union Semiconductor
Package SOT-23-3
Category PMIC
Pins 3

Ordering variants

  • UM1550S-18S
  • UM1550S-18Y
  • UM1550S-18B
  • UM1550S-18DA
  • UM1550S-18DB

CAD (KiCad official)

  • Symbol: UM1550S-18
  • Footprint: Package_TO_SOT_SMD:SOT-23-3
  • 3D model: SOT-23-3 (KiCad packages3D, STEP)

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

  • Datasheet: Union Semiconductor datasheet (None pp, sha256 5b58f5aaa3517fb0, retrieved 2026-08-17, tier: lcsc)
  • Extractor: ds2sf (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
  • CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF

Symbol & Footprint

Schematic Symbol

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PCB Footprint

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Datasheet

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