Power Management Power Control Offline Controllers/PFC

Obsolete

For New Designs

LT1725 - General Purpose Isolated Flyback Controller

LT1105 - Offline Switching Regulator

Features

  • Obsolete - Datasheet For Information Purposes Only.  Contact Linear Technology for Potential Replacement
  • ±1% Line and Load Regulation with No Optocoupler
  • Switch Frequency Up to 200kHz
  • Internal 2A Switch and Current Sense (LT1103)
  • Internal 1A Totem-Pole Driver (LT1105)
  • Start-Up Mode Draws Only 200µA
  • Fully Protected Against Overloads
  • Overvoltage Lockout of Main Supply
  • Protected Against Underdrive or Overdrive to FET
  • Operates in Continuous or Discontinuous Mode
  • Ideal for Flyback and Forward Topologies
  • Isolated Flyback Mode Has Fully Floating Outputs

Typical Application

LT1105 Typical Application
LT1105 Typical Application

Description

Obsolete - Datasheet For Information Purposes Only.  Contact Linear Technology for Potential Replacement

The LT®1103 Offline Switching Regulator is designed for high input voltage applications using an external FET switch whose source is driven by the open collect or output of the LT1103. The LT1103 is optimized for 15W to 100W applications. For higher power applications or additional switch current flexibility, the LT1105 is available and its totem pole output drives the gate of an external FET. Unique design of the LT1103/LT1105 eliminates the need for an optocoupler while still providing ±1% load and line regulation in a magnetic flux-sensed converter. This significantly simplifies the design of offline power supplies and reduces the number of components which must cross the isolation barrier to one, the transformer.

The LT1103/LT1105 current mode switching techniques are well suited to transformer isolated flyback and forward topologies while providing ease of frequency compensation with a minimum of external components. Low external part count for a typical application combines with a

Packaging

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

LT1105 Package Drawing
LT1105 Package Drawing
LT1105 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

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

  • Up to 250W Isolated Mains Converter
  • Up to 50W Isolated Telecom Converter
  • Fully Isolated Multiple Outputs
  • Distributed Power Conversion Networks

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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:
LT1105

Technical Support