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LT3845A - High Voltage Synchronous Current Mode Step-Down Controller with Adjustable Operating Frequency

The LT3845A is a high voltage, synchronous, current mode controller used for medium to high power, high efficiency supplies. It offers a wide 4V to 60V input range (7.5V minimum start-up voltage). An onboard regulator simplifies the biasing requirements by providing IC power directly from VIN.

Burst Mode® operation maintains high efficiency at light loads by reducing IC quiescent current to 120μA. Light load efficiency is also improved with the reverse inductor current inhibit function which supports discontinuous operation.

Additional features include adjustable fixed operating frequency that can be synchronized to an external clock for noise sensitive applications, gate drivers capable of driving large N-channel MOSFETs, a precision undervoltage lockout, 10μA shutdown current, short-circuit protection and a programmable soft-start.

The LT3845A is available in a 16-lead thermally enhanced TSSOP package.

Features High Voltage Operation: Up to 60V Synchronizable Up to 600kHz Adjustable Constant Frequency: 100kHz to 500kHz Output Voltages Up to 36V Stable Operation in Current Limit Adaptive Nonoverlap Circuitry Prevents Switch Shoot-Through Reverse Inductor Current Inhibit for Discontinuous Operation Improves Efficiency with Light Loads Programmable Soft-Start 120μA No Load Quiescent Current 10μA Shutdown Supply Current 1% Regulation Accuracy Standard Gate N-Channel Power MOSFETs Reverse Overcurrent Protection 16-Lead Thermally Enhanced TSSOP Package Typical Application

Applications 12V and 42V Automotive and Heavy Equipment 48V Telecom Power Supplies Avionics and Industrial Control Systems Distributed Power Converters Packaging

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