LT1111 Datasheet | Linear Technology

Features s Operates at Supply Voltages from 2V to 30V s Works with Surface Mount Inductors s 72k Hz Oscillator s Only Three External ponents Required s Step-Up or Step-Down Mode s Low-Battery Detector parator On-Chip s User Adjustable Current Limit s Internal 1A Power Switch s Fixed or Adjustable Output Voltage Versions s Space Saving 8-Pin Mini DIP 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 puters s Cellular Telephones s Portable Instruments s Flash Memory VPP Generators 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 ponents 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 72k Hz, optimizing the device to work with off-the-shelf surface mount inductors. The device can deliver 5V at 100m A from a 3V input in step-up mode or 5V at 200m A 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 amplifier. For input sources of less than 2V use the LT1110. , LTC and LT are registered trademarks of Linear Technology Corporation TYPICAL APPLICATIO All Surface Mount 3V to 5V Step-Up Converter 3V INPUT SUMIDA CD54-220M 22µH MBRS120T3 5V 100m A ILIM V IN + SW1 10µF- LT1111CS8-5 SENSE GND SW2 + 33 µ F - OPTIONAL - TA01 OUTPUT VOLTAGE (V) Typical Load Regulation 5 4 VIN = 2V 2.2 2.4 2.6 2.8 3V 0 0 25 50 75 100 125 150 175...