High Voltage, 3A, 500kHz Step-Down Switching Regulator

The LT3431 is a 500kHz monolithic buck switching regulator that accepts input voltages up to 60V. A high efficiency 3A, 0.1Ω switch is included on the die along with all the necessary oscillator, control and logic circuitry. A current mode architecture provides fast transient response and good loop stability.

Special design techniques and a new high voltage process achieve high efficiency over a wide input range. Efficiency is maintained over a wide output current range by using the output to bias the circuitry and by utilizing a supply boost capacitor to saturate the power switch. Patented circuitry maintains peak switch current over the full duty cycle range. A shutdown pin reduces supply current to 30µA and the device can be externally synchronized from 580kHz to 700kHz with logic level inputs.

The LT3431 is available in a thermally enhanced 16-pin TSSOP package.

Applications

* Industrial and Automotive Power Supplies

* Portable Computers

* Battery Chargers

* Distributed Power Systems

* Wide Input Range: 5.5V to 60V

* 3A Peak Switch Current

* Small Thermally Enhanced 16-Pin TSSOP Package

* Constant 500kHz Switching Frequency

* Saturating Switch Design: 0.1Ω

* Peak Switch Current Maintained Over Full Duty Cycle Range

* Effective Supply Current: 2.5mA

* Shutdown Current: 30µA

* 1.2V Feedback Reference Voltage

* Easily Synchronizable

* Cycle-by-Cycle Current Limiting