LT1111 - Micropower DC/DC Converter Adjustable and Fixed 5V, 12V

Features

  • 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

Typical Application

LT1111 Typical Application
LT1111 Typical Application

Description

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.

Packaging

CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.

For complete and up to date package information and drawings, please refer to our packaging page

Part Number Package Code Temp Package
Drawing
RoHS
LT1111CN8-12#PBF N-8 N C 05-08-1510 (N8) Yes
LT1111CN8-5#PBF N-8 N C 05-08-1510 (N8) Yes
LT1111CN8#PBF N-8 N C 05-08-1510 (N8) Yes
LT1111CS8-12#PBF SO-8 S8 C 05-08-1610 (S8) Yes
LT1111CS8-12#TRPBF SO-8 S8 C 05-08-1610 (S8) Yes
LT1111CS8-5#PBF SO-8 S8 C 05-08-1610 (S8) Yes
LT1111CS8-5#TRPBF SO-8 S8 C 05-08-1610 (S8) Yes
LT1111CS8#PBF SO-8 S8 C 05-08-1610 (S8) Yes
LT1111CS8#TRPBF SO-8 S8 C 05-08-1610 (S8) Yes
LT1111IS8#PBF SO-8 S8 I 05-08-1610 (S8) Yes
LT1111IS8#TRPBF SO-8 S8 I 05-08-1610 (S8) Yes


LT1111 Package Drawing
LT1111 Package Drawing

Order Info

  • Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
  • Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
  • Please refer to our general ordering information or the product datasheet for more details

Package Variations and Pricing

Part Number Package Temp Price
(1-99)
Price
(1k)*
RoHS
LT1111CN8-12#PBF N-8 C $2.83 $2.30 Yes
LT1111CN8-5#PBF N-8 C $2.83 $2.30 Yes
LT1111CN8#PBF N-8 C $2.83 $2.30 Yes
LT1111CS8-12#PBF SO-8 C $3.25 $2.65 Yes
LT1111CS8-12#TRPBF SO-8 C $2.71 Yes
LT1111CS8-5#PBF SO-8 C $3.25 $2.65 Yes
LT1111CS8-5#TRPBF SO-8 C $2.71 Yes
LT1111CS8#PBF SO-8 C $3.25 $2.65 Yes
LT1111CS8#TRPBF SO-8 C $2.71 Yes
LT1111IS8#PBF SO-8 I $4.25 $3.45 Yes
LT1111IS8#TRPBF SO-8 I $3.51 Yes
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* The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Linear Technology sales office or authorized distributor.

Demo Boards

Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.

Click here to view our complete list of demo boards

Applications

  • 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

Product Notifications

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Design Tools

LTspice

LTspice® software is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice

To launch a ready to run LTspice demonstration circuit for this part:

  • Step 1: If you have not installed LTspice on this computer, download and install LTspice
  • Step 2: Once LTspice is installed, click on the link(s) below to launch the simulation
  • Step 3: If LTspice does not automatically open after clicking the link above, you can instead run the simulation by right clicking on the link and selecting "Save Target As." After saving the file to your computer, start LTspice and open the demonstration circuit by selecting 'Open' from the 'File' menu

To explore other ready to run LTspice demonstration circuits, please visit our Demo Circuits Collection.

Models for the following parts are available in LTspice:
LT1111
LT1111-12
LT1111-5

Technical Support