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 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
• Current Limit Unaffected by Duty Cycle
• Reverse Overcurrent Protection
• 16-Lead Thermally Enhanced TSSOP Package, 16-Pin PDIP

Typical Application

Description

The LT3845 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 V_IN.

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 LT3845 is available in a 16-lead thermally enhanced TSSOP package and 16-pin through hole N package.