DESCRIPTION
The LTC®3705 is a controller for a 2-switch forward converter and includes on-chip bottom and top gate drivers that do not require external transformers.
For secondary-side control, combine the LTC3705 with the LTC3706 PolyPhase® secondary-side synchronous forward controller to create a complete forward converter using a minimum of discrete parts. A proprietary scheme is used to multiplex gate drive signals across the isolation barrier through a tiny pulse transformer. The on-chip rectifier and the same pulse transformer provide gate drive bias power.

FEATURES
■ High-Speed Top and Bottom Gate Drivers for
   2-Switch Forward Converter
■ On-Chip Rectifier and Self-Starting Architecture
   Eliminate Need for Separate Gate Drive Bias
   Supply
■ Wide Input Voltage Supply Range: 18V to 80V
■ Tolerant of 100V Input Voltage Transients
■ Linear Regulator Controller for Fast Start-Up
■ Precision UVLO with Adjustable Hysteresis
■ Overcurrent Protection
■ Volt-Second Limit Prevents Transformer Core
   Saturation
■ Voltage Feedforward for Fast Transient Response
■ Available in 16-Lead Narrow SSOP Package

APPLICATIONS
■ Isolated 48V Telecommunication Systems
■ Internet Servers and Routers
■ Distributed Power Step-Down Converters
■ Automotive and Heavy Equipment