Features

• 5.5V to 100V Input Voltage Range
• 450mA, 150V Internal DMOS Power Switch
• Up to 5W of Output Power
• Low Quiescent Current:
   70μA in Sleep Mode
   280μA in Active Mode
• Boundary Mode Operation at Heavy Load
• Low-Ripple Burst Mode® Operation at Light Load
• Minimum Load <0.5% (Typ) of Full Output
• V_OUT Set with a Single External Resistor
• No Transformer Third Winding or Opto-Isolator
• Required for Regulation
• Accurate EN/UVLO Threshold and Hysteresis
• Internal Compensation and Soft-Start
• 5-Lead TSOT-23 Package

Typical Application

Description

The LT8303 is a micropower high voltage isolated flyback converter. By sampling the isolated output voltage directly from the primary-side flyback waveform, the part requires no third winding or opto-isolator for regulation. The output voltage is programmed with a single external resistor. Internal compensation and soft-start further reduce external component count. Boundary mode operation provides a small magnetic solution with excellent load regulation. Low ripple Burst Mode operation maintains high efficiency at light load while minimizing the output voltage ripple. A 450mA, 150V DMOS power switch is integrated along with all high voltage circuitry and control logic into a 5-lead thinSOT™ package.

The LT8303 operates from an input voltages range of 5.5V to 100V and can deliver up to 5W of isolated output power. The high level of integration and the use of boundary and low ripple burst modes result in a simple to use, low component count, and high efficiency application solution for isolated power delivery.