| Quantity | Unit Price | Total Price |
|---|---|---|
| 1 | $1.88 | $1.88 |
| 15+ | $0.43 | $6.45 |
| 25+ | $0.42 | $10.50 |
| 50+ | $0.40 | $20.00 |
| 100+ | $0.35 | $35.00 |
| N+ | $0.07 | Price Inquiry |
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| Product attributes | Property Value |
| Manufacturer | Union Semiconductor International Limited |
| Product Series | UM1550 |
| Packaging | Tape & Reel (TR) | |
| Output Configuration | Positive |
| Output Type | Fixed |
| Number of Regulators | 1 |
| Voltage - Input (Max) | 8V |
| Voltage - Output (Min/Fixed) | - |
| 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-243AA |
| Supplier Device Package | SOT-89-3 |
| ROHS |
The UM1550B is a high-performance low dropout linear regulator from Union Semiconductor, delivering a fixed 1.0V output with up to 300mA of current. Its ultra-low 3.5µA quiescent current makes it an excellent choice for battery-operated and energy-harvesting applications. The device features a low dropout voltage of 0.3V at 200mA, ensuring efficient operation even with minimal input-to-output headroom. Housed in a compact SOT-89-3 package, the UM1550B offers excellent power supply rejection of 56dB at 100Hz, providing clean and stable power for sensitive electronics.
- Extended Battery Life: Ultra-low 3.5µA quiescent current reduces standby drain, ideal for always-on IoT devices.
- High Efficiency at Low Headroom: Dropout of just 0.3V @ 200mA allows operation close to the output voltage, minimizing power dissipation.
- Compact Footprint: SOT-89-3 package saves PCB space while providing adequate thermal performance for 300mA loads.
- Low Noise Operation: PSRR of 56dB at 100Hz filters mains-frequency ripple, ensuring clean supply for analog circuits.
Battery-Powered IoT Sensors
With a quiescent current of only 3.5µA, the UM1550B minimizes standby power consumption, extending battery life in wireless sensor nodes and smart home devices.
Portable Medical Devices
The 300mA output current and low dropout of 0.3V @ 200mA ensure stable power for glucose monitors and pulse oximeters, even as batteries discharge.
Wearable Electronics
The compact SOT-89-3 package and low quiescent current make it ideal for fitness trackers and smartwatches where PCB space and power efficiency are critical.
Industrial Control Modules
Provides clean, regulated 1.0V supply for microcontrollers and logic ICs in industrial sensors, with PSRR of 56dB at 100Hz to reject low-frequency noise.
Energy Harvesting Systems
The ultra-low quiescent current allows the regulator to operate efficiently with intermittent energy sources like solar cells or thermoelectric generators.
Automotive Interior Lighting
Stable 1.0V output for LED driver control circuits, with dropout performance that maintains regulation during cold-crank voltage dips.
- Q: What is the output voltage of the UM1550B?
- A: The UM1550B is a fixed-output LDO regulator with a 1.0V output (output type: 1).
- Q: What is the maximum output current?
- A: The UM1550B 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 technical data; please refer to the official datasheet for this parameter.
- Q: What is the dropout voltage?
- A: The dropout voltage is 0.3V at 200mA load current, ensuring efficient operation with low headroom.
- Q: What is the quiescent current?
- A: The quiescent current is extremely low at 3.5µA, making it ideal for battery-powered applications.
- Q: What package is available?
- A: The UM1550B is offered in the SOT-89-3 package, suitable for compact PCB layouts.
- Q: What is the output voltage of the UM1550B?
- A: The UM1550B is a fixed-output LDO regulator with a 1.0V output (output type: 1).
- Q: What is the maximum output current?
- A: The UM1550B 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 technical data; please refer to the official datasheet for this parameter.
- Q: What is the dropout voltage?
- A: The dropout voltage is 0.3V at 200mA load current, ensuring efficient operation with low headroom.
- Q: What is the quiescent current?
- A: The quiescent current is extremely low at 3.5µA, making it ideal for battery-powered applications.
- Q: What package is available?
- A: The UM1550B is offered in the SOT-89-3 package, suitable for compact PCB layouts.

UM1550B.pdf