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Key Specifications
Part Number Description Status SubFamily Regulated Outputs(.) Vin(Min)(V) Vin(Max)(V) Vout(Min)(V) Vout(Max)(V) Iout(Max)(A) Topology Special Features Frequency(kHz) Operating Temperature Range (°C) Pin/Package EV Kit Available?
UM3503QA 1A, 2.5V to 5.5V Input, Low Profile Power Module ACTIVE Step-Down (Buck) Converter 1 2.5 5.5 1 5 1 Synchronous Buck Enable, Pulse Skipping Mode, Integrated Inductor 2250 -40 to 85 24/QFN 4.0×4.0 Y
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Product Description
 
The UM3503QA is a complete 1A, DC/DC step-down power supply intended for low-power applications. It is capable of delivering 1A output current over a wide input voltage range from 2.5V to 5.5V. Switching regulator, inductor and input/output capacitors are integrated into a tiny 4mm×4mm×1.05mm QFN package. Unless the external resistor divider, no additional components are required to accomplish the design. The UM3503QA is engineered to simplify design and to minimize layout constraints. It is ideal replacement of discrete buck converter to save PCB space.
The UM3503QA is based on a synchronous step-down DC-DC converter optimized for battery-powered portable applications. The DC/DC converter enters the pulse skipping mode automatically at light load condition. This can increase efficiency. The operation frequency is set to 2.25MHz at normal load condition. The UM3503QA enters shutdown mode and consumes less than 1µA when EN pin is pulled low.
The UM3503QA is available in a compact and low profile QFN24 4.0mm×4.0mm×1.05mm package.
 
Features
 
- Ultra Small QFN Package 4.0× 4.0×1.05
- High Efficiency: Up to 90%
- 1A Output Current
- 0.6V Minimum Output Voltage
- 2.5V to 5.5V Input Voltage Range
- 2.25MHz Switching Frequency
- 56μA Quiescent Current
- <1µA Shutdown Current
- Excellent Load Transient and Line Transient
- Pulse Skipping Mode Operation
- Low Ripple at Light-Load Pulse Skipping Mode
- Thermal Fault Protection
 
 Typical Application Circuit  
                                                                             
 

Light Load Efficiency



Applications

- LDO Replacement
- FPGA and DSP Point-of-Load Regulator
- Cellular and Smart Phones
- MCU, DSP and FPGA Core Supplies
- Wireless and DSL Modems
- Portable Game Consoles and Instruments
- PDAs, GPS
- Bluetooth Headsets
- Battery-Powered Devices
 
Pin Configurations  
                
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Ordering Information
 
Part Number
Packaging Type
Marking Code
Shipping Qty
UM3503QA
QFN24 4.0×4.0
3503
3000pcs/13Inch
Tape & Reel
 
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