DESCRIPTION

· The LT1103/LT1105 Offline Switching Regulator is designed for high input voltage applications, utilizing an external FET switch.

· Optimized for 15W to 100W applications, with the LT1105 offering higher power and switch current flexibility.

· Eliminates the need for an optocoupler while maintaining ±1% load and line regulation in a magnetic flux-sensed converter.

· Suitable for transformer-isolated flyback and forward topologies, simplifying offline power supply designs.

FEATURES

· Switch frequency up to 200kHz with internal 2A switch and current sense (LT1103) or 1A totem-pole driver (LT1105).

· Start-up mode draws only 200mA, with full protection against overloads and overvoltage lockout of the main supply.

· Operates in continuous or discontinuous mode, ideal for flyback and forward topologies with fully floating outputs in isolated flyback mode.

APPLICATIONS

· Up to 250W isolated mains converter and up to 50W isolated telecom converter.

· Fully isolated multiple outputs and distributed power conversion networks.

· Typical applications include a fully isolated flyback 100kHz 50W converter with load regulation compensation.