Features

• 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: 0.2 Ohms
• 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

Typical Application

Description

The LT1956/LT1956-5 are 500kHz monolithic buck switching regulators with an input voltage capability up to 60V. A high efficiency 1.5A, 0.2 Ohm 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.