component
UM1540S-33
Public Made by Adomby adom
Union Semiconductor Voltage Regulators - Linear, Low Drop Out (LDO) Regulators, SOT23-5. Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.
3D Model
Open in new tab ↗
Loads when you scroll to it. Unloads after 5 minutes in the background.
Symbol & Footprint
Schematic Symbol
Open full view ↗Loads when you scroll to it. Unloads after 5 minutes in the background.
PCB Footprint
Open full view ↗Loads when you scroll to it. Unloads after 5 minutes in the background.
Datasheet
Open in new tab ↗Loads when you scroll to it. Unloads after 5 minutes in the background.
README
markdownUM1540S-33
Union Semiconductor · Voltage Regulators - Linear, Low Drop Out (LDO) Regulators · SOT23-5
UM1540S-33 from Union Semiconductor, in a SOT23-5. 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 for the LDO, with an input voltage range of 1.8V to 6V and an absolute maximum of -0.3V to +6.5V. |
| 2 | GND | power_in | Ground pin for the regulator, which the datasheet says should be connected to ground. |
| 3 | SHDN | input | Shutdown control input: high (VIH min 1.2V) activates the LDO and low (VIL max 0.4V) shuts it down. |
| 4 | NC | unconnected | Not connected. |
| 5 | VOUT | power_out | Regulated output of the LDO; the UM1540S-33 gives a fixed 3.3V output, with up to 300mA output current guaranteed. |
Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | Union Semiconductor |
| Package | SOT23-5 |
| 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 |
|---|---|---|---|---|---|---|---|
| Supply Voltage on VIN Pin | VIN | -0.3 | 6.5 | V | 5 | ||
| Voltage on VOUT Pin | VOUT | -0.3 | 6.5 | V | 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 @25°C (SOT23-5) | PD | 0.43 | W | Note 4, SOT23-5, @25°C | 5 | ||
| Package Thermal Resistance (SOT23-5) | θJA | 230 | °C/W | SOT23-5 | 5 | ||
| Input Voltage Range | VIN | 1.8 | 6 | V | 6 | ||
| Output Voltage Range | VOUT | 1.2 | 5 | V | 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 | ISHDN | 1 | μA | SHDN=VIN or GND | 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 |
| Startup Time Response | t | 80 | μs | VOUT=3.3V, RL=68Ω, COUT=1μF | 6 | ||
| Input Low Voltage (SHDN) | VIL | 0.4 | V | VIN=1.8V to 5V | 6 | ||
| Input High Voltage (SHDN) | VIH | 1.2 | V | VIN=1.8V to 5V | 6 | ||
| Output Voltage Temperature Coefficient | 60 | ppm/°C | TC -40°C to +125°C | 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 | |||
| Output Voltage Noise | 115 | μVRMS | VOUT=3.0V, f=10Hz to 100kHz, CIN=1μF, IOUT=100mA | 6 | |||
| Power Supply Ripple Rejection | PSRR | 56 | dB | VIN=VOUT+1V, IOUT=100mA, f=100Hz | 6 | ||
| Power Supply Ripple Rejection | PSRR | 42 | dB | VIN=VOUT+1V, IOUT=100mA, f=1kHz | 6 | ||
| ESD Rating Human Body Mode | 2 | kV | Human Body Mode | 6 |
CAD (KiCad official)
- Symbol:
UM1540S-33 - Footprint:
Package_TO_SOT_SMD:SOT-23-5 - 3D model: SOT23-5 (KiCad packages3D, STEP)
- 3D model files:
um1540s-33-etched.step/um1540s-33-etched.glbcarry the MPN laser-etched on the die in a toggleableAdom.LaserEtchgroup (Fusion-ready);um1540s-33.step/um1540s-33.glbare the bare package body.
Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- Datasheet: Union Semiconductor datasheet (17 pp, sha256
a2304bd57b300151, retrieved 2026-10-17, tier: lcsc) - Extractor: parts-factory
2.0.0/extract_pins 0.3, primaryclaude-haiku-5-5(text), consensusclaude-sonnet-5-5(agreed), 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).