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LTC3852 - Low Input Voltage, Synchronous Step-Down DC/DC Controller

The LTC3852 is a constant frequency, current mode step-down DC/DC controller which can be powered by an onboard charge pump. Input supplies as low as 2.7V, when doubled by the charge pump, provide 5V to the LTC3852’s control logic and gate drives, supporting a wide selection of logic-level N-channel power MOSFETs.

The constant-frequency current mode architecture allows for a phase-lockable fixed frequency of up to 750kHz. The RUN pin provides a precision enable threshold while the TRACK/SS pin combines tracking and adjustable soft-start features.

The MODE/PLLIN pin selects among Burst Mode® operation, pulse-skipping mode, and continuous current mode. Current foldback limits MOSFET power dissipation during short-circuit conditions. Reverse current and current foldback functions are disabled during soft-start. A power good output pin indicates when the output is within ±10% of its designed set point.

Features Charge Pump Input Range: 2.7V to 5.5V Controller Input Range: 4V to 38V Integrated Charge Pump Provides 5V Gate Drive to Logic Level MOSFETs RSENSE or DCR Current Sensing ±1.25% Output Voltage Accuracy Over Temperature Phase-Lockable Fixed Frequency: 250kHz to 750kHz Power Good Output Voltage Monitor Adjustable Soft-Start Voltage Ramping Current Foldback Disabled During Start-Up No Reverse Current During Soft-Start Selectable Constant Frequency, Pulse-Skipping, or Burst Mode Operation Output Overvoltage Protection Very Low Dropout Operation: 99% Duty Cycle Available in a 24-Lead (3mm x 5mm) QFN Package Typical Application

Applications General Purpose 3.3V Systems Lithium-Ion Powered Devices Distributed DC Power Systems Packaging

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