High Voltage, 1.5A, 500kHz Step-Down Switching Regulators

The LT1956/LT1956-5 are 500kHz monolithic buck switching regulators with an input voltage capability up to 60V. A high efficiency 1.5A, 0.2Ω 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 25µA and the device can be externally synchronized from 580kHz to 700kHz with a logic level input.

The LT1956/LT1956-5 are available in fused-lead 16-pin SSOP and thermally enhanced TSSOP packages.

Applications

* High Voltage, Industrial and Automotive

* Portable Computers

* Battery-Powered Systems

* Battery Chargers

* Distributed Power Systems

* Wide Input Range: 5.5V to 60V

* 1.5A Peak Switch Current

* Small 16-Pin SSOP Package or Thermally Enhanced TSSOP Package

* Saturating Switch Design: 0.2Ω

* Peak Switch Current Maintained Over Full Duty Cycle Range

* Constant 500kHz Switching Frequency

* Effective Supply Current: 2.5mA

* Shutdown Current: 25µA

* 1.2V Feedback Reference (LT1956)

* 5V Fixed Output (LT1956-5)

* Easily Synchronizable

* Cycle-by-Cycle Current Limiting