Features

• Wide Input Range: 5.5V to 60V
• 1.5A Peak Switch Current
• Constant 200kHz Switching Frequency
• Saturating Switch Design: 0.2Ω
• Peak Switch Current Rating Maintained Over Full Duty Cycle Range
• Low Effective Supply Current: 2.5mA
• Low Shutdown Current: 25μA
• 1.2V Feedback Reference Voltage (LT1766)
• 5V Fixed Output (LT1766-5)
• Easily Synchronizable
• Cycle-by-Cycle Current Limiting
• Small 16-Pin SSOP and Thermally Enhanced TSSOP Packages

Typical Application

Description

The LT1766/LT1766-5 are 200kHz monolithic buck switching regulators that accept input voltages 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 control architecture delivers fast transient response and excellent 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 228kHz to 700kHz with logic-level inputs.

The LT1766/LT1766-5 are available in a 16-pin fused-lead SSOP package or a TSSOP package with exposed backside for improved thermal performance.