2A Step-Down Converter with Adjustable Input Current Limit

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Manufacturer Skyworks


Description :

The AAT1138 is a 2A synchronous step-down converter with an integrated current-limiting load switch designed for precise input current control applications. By guarding against excessive input current, the AAT1138 enables the system designer to maximize the output current from the step-down converter while protecting the input supply. It is designed for protection of 5V USB ports and 3.3V supplies from heavy load transient conditions commonly seen with high data rate modem applications. The AAT1138 integrates a programmable current limited P-channel MOSFET load switch to protect the input supply against large currents which may cause the supply to fall out of regulation. Current limit threshold is programmed by an external resistor from SET to ground. It can be adopted to control loads of the input supply that requires up to 1.4A. The AAT1138's internal step-down converter is a 2A, 1.2MHz constant frequency current mode PWM step-down converter. The step-down converter can run at 100% duty cycle for low dropout operation. The output voltage can be regulated as low as 0.6V. The AAT1138 is available in a Pb-free, low profile, 16-pin 3mm x 4mm TDFN package. The product is rated over the -40°C to 85°C temperature range.

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    • VIN Range: 2.5V to 5.5 V
    • VOUT Range: 0.6V to VPVIN
    • System Current Limited Load Switch
    • Programmable Over-Current Threshold
    • < 1μs Fast Transient Response to Short Current
    • 145mΩ Typical RDS(ON)
    • Step-Down Converter
    • Up to 2A Output Current
    • 95% Peak Efficiency
    • 1.2MHz Switching Frequency
    • 135mΩ Low RDS(ON) Internal Switches
    • 100% Duty Cycle Low Dropout Operation
    • Soft Start
    • Under-Voltage Lockout
    • Independent Enable Pins
    • <2μA Shutdown Current
    • Over-Temperature and Current Limit Protection
    • Low Profile 16-pin 3mm x 4mm TDFN Package
    • -40°C to 85°C Temperature Range

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Features Similar products
Control scheme Slope Compensated Peak Current Mode Control  

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Switching frequency (kHz) 1200  
Max Input Voltage (V) 2.5 to 5.5  
Output Voltage (V) 0.6 to 5.5  
Typ. Active Current (µA) 300  
Typ. Dropout Voltage @ Max. lout (mV) 400 Max  
Output Capacitor Type X5R or X7R Ceramic Capacitor  
Output Current (mA) 2000  
Operating Temperature (°C) -40 to +85  
Package TDFN34-16