Features

• Wide Input Voltage Range: 3V to 60V
• Low Quiescent Current: 6mA
• Internal 5A Switch
  (2.5A for LT1171, 1.25A for LT1172)
• Shutdown Mode Draws Only 50μA Supply Current
• Very Few External Parts Required
• Self-Protected Against Overloads
• Operates in Nearly All Switching Topologies
• Flyback-Regulated Mode Has Fully Floating Outputs
• Comes in Standard 5-Pin Packages
• LT1172 Available in 8-Pin MiniDIP and Surface Mount Packages
• Can Be Externally Synchronized

Typical Application

Description

The LT®1170/LT1171/LT1172 are monolithic high power switching regulators. They can be operated in all standard switching configurations including buck, boost, flyback, forward, inverting and “Cuk.” A high current, high efficiency switch is included on the die along with all oscillator, control and protection circuitry. Integration of all functions allows the LT1170/LT1171/LT1172 to be built in a standard 5-pin TO-3 or TO-220 power package as well as the 8-pin packages (LT1172). This makes them extremely easy to use and provides “bust proof” operation similar to that obtained with 3-pin linear regulators.

The LT1170/LT1171/LT1172 operate with supply voltages from 3V to 60V, and draw only 6mA quiescent current. They can deliver load power up to 100W with no external power devices. By utilizing current-mode switching techniques, they provide excellent AC and DC load and line regulation.

The LT1170/LT1171/LT1172 have many unique features not found even on the vastly more difficult to use low power control chips presently available. They use adaptive antisat switch drive to allow very wide ranging load currents with no loss in efficiency. An externally activated shutdown mode reduces total supply current to 50μA typically for standby operation.