Union Semiconductor International Limited UM1550S-18
| Quantity | Unit Price | Total Price |
|---|---|---|
| 1 | $1.40 | $1.40 |
| 15+ | $0.32 | $4.80 |
| 25+ | $0.32 | $8.00 |
| 50+ | $0.30 | $15.00 |
| 100+ | $0.26 | $26.00 |
| N+ | $0.05 | Price Inquiry |
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| Product attributes | Property Value |
| Manufacturer | Union Semiconductor International Limited |
| Product Series | |
| Packaging | Tape & Reel (TR) | |
| Output Configuration | Positive |
| Output Type | Fixed |
| Number of Regulators | 1 |
| Voltage - Input (Max) | 8V |
| Voltage - Output (Min/Fixed) | 1.8V |
| Voltage - Output (Max) | - |
| Voltage Dropout (Max) | 0.3V @ 200mA |
| Current - Output | 300mA |
| Current - Quiescent (Iq) | 3.5 µA |
| Current - Supply (Max) | - |
| PSRR | 56dB ~ 42dB (100Hz ~ 1kHz) |
| Control Features | - |
| Protection Features | Over Current, Over Temperature |
| Operating Temperature | -40°C ~ 125°C (TJ) |
| Grade | - |
| Qualification | - |
| Mounting Type | Surface Mount |
| Package / Case | TO-236-3, SC-59, SOT-23-3 |
| Supplier Device Package | SOT-23-3 |
| ROHS |
The UM1550S-18 is a high-performance low dropout linear regulator from Union Semiconductor, delivering a fixed 1.8V output with up to 300mA of current. Its ultra-low quiescent current of 3.5 µA makes it an excellent choice for battery-operated and energy-efficient designs. The device offers a low dropout voltage of just 0.3V at 200mA, ensuring efficient operation even with minimal input-to-output headroom. Housed in a compact SOT-23-3 package, it is ideal for space-constrained applications requiring stable and clean power delivery.
- Extended Battery Life: Ultra-low 3.5 µA quiescent current minimizes power drain in standby mode, ideal for portable devices.
- High Efficiency at Low Headroom: Low dropout voltage of 0.3V @ 200mA allows operation with small input-output differentials, reducing power dissipation.
- Compact Footprint: SOT-23-3 package saves PCB space, perfect for miniaturized electronics.
- Clean Power Output: PSRR of 56dB to 42dB (100Hz-1kHz) suppresses supply noise, ensuring stable performance for sensitive circuits.
Battery-Powered IoT Sensors
With an ultra-low quiescent current of 3.5 µA, the UM1550S-18 minimizes standby power consumption, significantly extending battery life in wireless sensors and smart home devices.
Portable Medical Devices
The stable 1.8V output and low dropout voltage ensure reliable operation for low-power medical monitors and wearable health trackers, where consistent voltage is critical for accurate readings.
Wearable Electronics
The compact SOT-23-3 package and 300mA current capability make it suitable for space-constrained wearables like smartwatches and fitness bands, providing efficient power conversion from a single-cell battery.
Low-Power Microcontrollers
Modern MCUs operating at 1.8V benefit from the UM1550S-18's clean output and fast transient response, ensuring stable operation during active processing and sleep mode transitions.
Energy Harvesting Systems
For systems powered by solar cells or thermoelectric generators, the low dropout voltage of 0.3V allows efficient regulation even when the input voltage is close to the output, maximizing energy utilization.
Audio and Sensor Signal Conditioning
The PSRR of 56dB to 42dB (100Hz to 1kHz) helps filter power supply noise, making it suitable for analog sensor interfaces and low-noise audio circuits requiring a clean 1.8V rail.
- Q: What is the output voltage of the UM1550S-18?
- A: The UM1550S-18 provides a fixed output voltage of 1.8V.
- Q: What is the maximum output current?
- A: It can deliver up to 300mA of continuous output current.
- Q: What is the input voltage range?
- A: The input voltage range is not specified in the provided data; please refer to the datasheet for the full operating range.
- Q: What is the dropout voltage?
- A: The dropout voltage is 0.3V at a 200mA load.
- Q: What is the quiescent current?
- A: The quiescent current is very low at 3.5 µA, making it ideal for battery-powered applications.
- Q: What package is available?
- A: The UM1550S-18 is available in the compact SOT-23-3 package.
- Q: What is the output voltage of the UM1550S-18?
- A: The UM1550S-18 provides a fixed output voltage of 1.8V.
- Q: What is the maximum output current?
- A: It can deliver up to 300mA of continuous output current.
- Q: What is the input voltage range?
- A: The input voltage range is not specified in the provided data; please refer to the datasheet for the full operating range.
- Q: What is the dropout voltage?
- A: The dropout voltage is 0.3V at a 200mA load.
- Q: What is the quiescent current?
- A: The quiescent current is very low at 3.5 µA, making it ideal for battery-powered applications.
- Q: What package is available?
- A: The UM1550S-18 is available in the compact SOT-23-3 package.

UM1550S-18.pdf