Features

• 4.5V to 100V Input Voltage Range
• Internal 420mA, 150V Power Switch
• Boundary Mode Operation
• No Transformer Third Winding or Opto-Isolator Required for Regulation
• Improved Primary-Side Winding Feedback Load Regulation
• V_OUT Set with Two External Resistors
• BIAS Pin for Internal Bias Supply and Power Switch Driver
• No External Start-Up Resistor
• 16-Lead MSOP Package

Typical Application

Description

The LT3512 is a high voltage monolithic switching regulator specifically designed for the isolated flyback topology. No third winding or opto-isolator is required for regulation as the part senses output voltage directly from the primary-side flyback waveform. The device integrates a 420mA, 150V power switch, high voltage circuitry, and control into a high voltage 16-lead MSOP package with four leads removed.

The LT3512 operates from an input voltage range of 4.5V to 100V and delivers up to 4.5W of isolated output power. Two external resistors and the transformer turns ratio easily set the output voltage. Off-the-shelf transformers are available for several applications. The high level of integration and the use of boundary mode operation results in a simple, clean, tightly regulated application solution to the traditionally tough problem of isolated power delivery.