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UM1540S-18

Public Made by Adom

by adom

Union Semiconductor Voltage Regulators - Linear, Low Drop Out (LDO) Regulators, SOT-23-5. Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.

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UM1540S-18

Union Semiconductor · Voltage Regulators - Linear, Low Drop Out (LDO) Regulators · SOT-23-5

UM1540S-18 from Union Semiconductor, in a SOT-23-5. Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin Name Type Function
1 VIN power_in Supply input; the datasheet specifies an input voltage range of 1.8V to 6V, with absolute maximum of -0.3V to +6.5V.
2 GND power_in Ground reference pin for the regulator.
3 SHDN input Shutdown control input: high (VIH min 1.2V) activates the LDO and low (VIL max 0.4V) shuts it down, for VIN between 1.8V and 5V.
4 NC unconnected Not connected.
5 VOUT power_out Voltage regulated output; fixed output from 1.2V to 5.0V with guaranteed output current of 300mA.

Key specifications

Parameter Value
Manufacturer Union Semiconductor
Package SOT-23-5
Category Power Management (PMIC)
Pins 5

Electrical characteristics

Limits as printed in the datasheet (page.json metadata.characteristics carries them as data).

Parameter Symbol Min Typ Max Unit Conditions Page
Input Voltage Range VIN 1.8 6 V 6
Output Voltage Range VOUT 1.2 5 V 6
Output Current IOUT 300 mA 6
Output Voltage Accuracy -2.5 2.5 % 1mA≤IOUT≤250mA 6
Dropout Voltage ΔVDO 250 330 mV IOUT=200mA 6
Output Current Limit ILIMIT 350 450 550 mA RL=1Ω 6
Input Low Voltage VIL 0.4 V VIN=1.8V to 5V 6
Input High Voltage VIH 1.2 V VIN=1.8V to 5V 6
Operating Quiescent Current IQ 1 1.5 μA VIN=5V, IOUT=0mA 6
Shut Down Quiescent Current 1 μA VIN=5V, SHDN=GND 6
Input Current SHDN ISHDN 1 μA SHDN=VIN or GND 6
Line Regulation 0.3 %/V VOUT+0.3V≤VIN≤5V or VIN>1.8V, IOUT=10mA 6
Load Regulation 0.6 % VIN=VOUT+1V or VIN>1.8V, 1mA≤IOUT≤250mA 6
Input Voltage VIN -0.3 6.5 V Supply Voltage on VIN Pin 5
Output Voltage VOUT -0.3 6.5 V Voltage on VOUT Pin 5
Operating Junction Temperature TJ -40 125 °C Note 2, 3 5
Storage Temperature Range TSTG -65 150 °C 5
Lead Temperature for Soldering TL 260 °C 10 Seconds 5
Power Dissipation PD 0.43 W SOT23-5, @25°C, Note 4 5
Output Voltage TC 60 ppm/°C TC -40°C to +125°C 6
Output Voltage Noise 115 μVRMS VOUT=3.0V, f=10Hz to 100kHz, CIN=1μF, IOUT=100mA 6
Power Supply Ripple Rejection f=100Hz PSRR 56 dB VIN=VOUT+1V, IOUT=100mA, f=100Hz 6
Power Supply Ripple Rejection f=1kHz PSRR 42 dB VIN=VOUT+1V, IOUT=100mA, f=1kHz 6
ESD Rating 2 kV Human Body Mode 6
Package Thermal Resistance θJA 230 °C/W SOT23-5 5
Startup Time Response t 80 μs VOUT=3.3V, RL=68Ω, COUT=1μF 6

CAD (KiCad official)

  • Symbol: UM1540S-18
  • Footprint: Package_TO_SOT_SMD:SOT-23-5
  • 3D model: SOT-23-5 (KiCad packages3D, STEP)
  • 3D model files: um1540s-18-etched.step / um1540s-18-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); um1540s-18.step / um1540s-18.glb are the bare package body.

Provenance

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

  • Datasheet: Union Semiconductor datasheet (17 pp, sha256 a2304bd57b300151, retrieved 2026-10-27, tier: manufacturer)
  • Extractor: parts-factory 2.0.0 / extract_pins 0.3, primary claude-haiku-5-5 (text), consensus off (skipped (clean text read)), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish.
  • CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF