Description
The TOPSwitchfamily implements, with only three terminals, all functions necessary for a DC to DC, converter: high voltage N-channel power MOSFET with controlled turn-on gate driver, voltage mode PWM controller with integrated 120 kHz oscillator, high voltage start-up bias circuit, bandgap derived reference, bias shunt regulator/error amplifier for loop compensation and fault protection circuitry.

Product Highlights
Low Cost Replacement for Discrete Switchers
• Up to 15 fewer components - cuts cost, increases reliability
• Allows for a smaller and lighter solution under 12 mm height, all surface mount components

Over 80% Efficiency in Flyback Topology
• Built-in start-up and current limit reduce DC losses
• Low capacitance MOSFET cuts switching losses
• CMOS controller/gate driver consumes only 7 mW
• 70% maximum duty cycle minimizes conduction losses

Simplifies Design - Reduces Time to Market
• Integrated PWM Controller and high power MOSFET
• Only one external capacitor needed for compensation, bypass and start-up/auto-restart functions

System Level Fault Protection Features
• Auto-restart and cycle by cycle current limiting functions handle both primary and secondary faults
• On-chip latching thermal shutdown protects the entire system against overload

Highly Versatile
• Implements Buck, Boost, Flyback or Forward topology
• Easily interfaces with both opto and primary feedback
• Supports continuous or discontinuous mode of operation
• Specified for operation down to 16 V DC input