LT1111

U U FEATURES s Operates at Supply Voltages from 2V to 30V s Works with Surface Mount Inductors s 72kHz Oscillator s Only Three External Components Required s Step-Up or Step-Down Mode s Low-Battery Detector Comparator On-Chip s User Adjustable Current Limit s Internal 1A Power Switch s Fixed or Adjustable Output Voltage Versions s Space Saving 8-Pin MiniDIP or SO-8 Package U APPLICATIO S s 3V to 5V, 5V to 12V Converters s 9V to 5V, 12V to 5V Converters s Remote Controls s Peripherals and Add-On Cards s Battery Backup Supplies s Uninterruptible Supplies s Laptop and Palmtop Computers s Cellular Telephones s Portable Instruments s Flash Memory VPP Generators LT1111 Micropower DC/DC Converter Adjustable and Fixed 5V, 12V DESCRIPTIO The LT®1111 is a versatile micropower DC/DC converter. The device requires only three external components to deliver a fixed output of 5V or 12V. Supply voltage ranges from 2V to 12V in step-up mode and to 30V in step-down mode. The LT1111 functions equally well in step-up, stepdown, or inverting applications. The LT1111 oscillator is set at 72kHz, optimizing the device to work with off-the-shelf surface mount inductors. The device can deliver 5V at 100mA from a 3V input in step-up mode or 5V at 200mA from a 12V input in stepdown mode. Switch current limit can be programmed with a single resistor. An auxiliary open-collector gain block can be configured as a low-battery detector, linear post regulator, undervoltage lock-out circuit, or error amplifi...