LT1111 Datasheet

• Operates at Supply Voltages from 2V to 30V
• Works with Surface Mount Inductors
• 72kHz Oscillator
• Only Three External Components Required
• Step-Up or Step-Down Mode
• Low-Battery Detector Comparator On-Chip
• User Adjustable Current Limit
• Internal 1A Power Switch
• Fixed or Adjustable Output Voltage Versions
• Space Saving 8-Pin MiniDIP or SO-8 Package

• 3V to 5V, 5V to 12V Converters
• 9V to 5V, 12V to 5V Converters
• Remote Controls
• Peripherals and Add-On Cards
• Battery Backup Supplies
• Uninterruptible Supplies
• Laptop and Palmtop Computers
• Cellular Telephones
• Portable Instruments
• Flash Memory VPP Generators

The LT1111 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, step-down, 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 step-down 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.