Power Management Switching Regulator Step-Up (Boost) Regulators Internal Power Switch Boost

LT1109 - Micropower Low Cost DC/DC Converter Adjustable and Fixed 5V, 12V

Features

  • Uses Off-the-Shelf Inductors
  • Only 33µH Inductor Required
  • Low Cost
  • 3-Lead TO-92, SO8, or 8-Pin DIP
  • Adjustable or Fixed 5V or 12V Output
  • Adjustable or Fixed 5V or 12V Output
  • Only Three External Components Required
  • 320µA IQ
  • 1.6V Minimum Start-Up Voltage
  • Logic Controlled Shutdown

Typical Application

LT1109 Typical Application
LT1109 Typical Application
LT1109 Typical Application

Description

The LT1109 is a simple step-up DC/DC converter. Avail-able in 8-pin SO, 3-lead TO-92 (fixed output only) or miniDIP packages, the devices require only three external components to construct a complete DC/DC converter. Current drain is just 320uA at no load, making the device ideal for cost-sensitive applications where standby current must be kept to a minimum. The LT1109-5 can deliver 5V at 100mA from a 3V input and the LT1109-12 can deliver 12V at 60mA from a 5V input. The 8-pin versions also feature a logic controlled SHUTDOWN pin that turns off the oscillator when taken low. The gated-oscillator design requires no frequency compensation components. The high frequency 120kHz oscillator permits the use of small surface mount inductors and capacitors. For a 5V to 12V at 120mA converter, see the LT1109A. For a 5V to 12V at 200mA converter with 20µA shutdown current, see the LT1301.

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
LT1109CN8-12#PBF N-8 N C 05-08-1510 (N8) Yes
LT1109CN8-5#PBF N-8 N C 05-08-1510 (N8) Yes
LT1109CN8#PBF N-8 N C 05-08-1510 (N8) Yes
LT1109CS8-12#PBF SO-8 S8 C 05-08-1610 (S8) Yes
LT1109CS8-12#TRPBF SO-8 S8 C 05-08-1610 (S8) Yes
LT1109CS8-5#PBF SO-8 S8 C 05-08-1610 (S8) Yes
LT1109CS8-5#TRPBF SO-8 S8 C 05-08-1610 (S8) Yes
LT1109CS8#PBF SO-8 S8 C 05-08-1610 (S8) Yes
LT1109CS8#TRPBF SO-8 S8 C 05-08-1610 (S8) Yes
LT1109CZ-12#PBF TO-92 Z C 05-08-1410 Yes
LT1109CZ-5#PBF TO-92 Z C 05-08-1410 Yes


LT1109 Package Drawing
LT1109 Package Drawing
LT1109 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
LT1109CN8-12#PBF N-8 C $2.92 $2.35 Yes
LT1109CN8-5#PBF N-8 C $2.92 $2.35 Yes
LT1109CN8#PBF N-8 C $2.92 $2.35 Yes
LT1109CS8-12#PBF SO-8 C $2.92 $2.35 Yes
LT1109CS8-12#TRPBF SO-8 C $2.41 Yes
LT1109CS8-5#PBF SO-8 C $2.92 $2.35 Yes
LT1109CS8-5#TRPBF SO-8 C $2.41 Yes
LT1109CS8#PBF SO-8 C $2.92 $2.35 Yes
LT1109CS8#TRPBF SO-8 C $2.41 Yes
LT1109CZ-12#PBF TO-92 C $2.25 $1.80 Yes
LT1109CZ-5#PBF TO-92 C $2.25 $1.80 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.

Part Number Description Price Documentation
DC019A LT1109CS8 | +5V TO +12V FLASH MEMORY Vpp GENERATOR Contact Factory
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Click here to view our complete list of demo boards

Applications

  • Flash Memory VPP Generators
  • 3V to 5V Converters
  • 5V to 12V Converters
  • Disk Drives
  • PC Plug-In Cards
  • Peripherals
  • Battery-Powered Equipment

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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

Models for the following parts are available in LTspice:
LT1109
LT1109-12
LT1109-5
LT1109A
LT1109A-12
LT1109A-5

Technical Support