LT3845EFE

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

DESCRIPTION

The LT®3845 is a high voltage, synchronous, current mode controller used for medium to high power, high effi ciency supplies. It offers a wide 4V to 60V input range 7.5V minimum start-up voltage. An onboard regulator simplifi es 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.

FEATURES

■ High Voltage Operation: Up to 60V

■ Synchronizable Up to 600kHz

■ Adjustable Constant Frequency: 100kHz to 500kHz

■ Output Voltages Up to 36V

■ Adaptive Nonoverlap Circuitry Prevents Switch Shoot-Through

■ Reverse Inductor Current Inhibit for Discontinuous

   Operation Improves Effi ciency with Light Loads

■ Programmable Soft-Start

■ 120μA No Load Quiescent Current

■ 10μA Shutdown Supply Current

■ 1% Regulation Accuracy

■ Standard Gate N-Channel Power MOSFETs

■ Current Limit Unaffected by Duty Cycle

■ Reverse Overcurrent Protection

■ 16-Lead Thermally Enhanced TSSOP Package, 16-Pin PDIP

APPLICATIONS

■ 12V and 42V Automotive and Heavy Equipment

■ 48V Telecom Power Supplies

■ Avionics and Industrial Control Systems

■ Distributed Power Converters