ADI LTC1698ES#PBF

The LTC1698 is a precision secondary-side forward converter controller that synchronously drives external N -channel MOSFETs. It is designed for use with the LT3781 primary-side synchronous forward converter controller to create a completely isolated power supply. The LT3781 synchronizes the LTC1698 through a small pulse transformer and the LTC1698 drives a feedback optocoupler to close the feedback loop. Output accuracy of ±0.8% and high efficiency over a wide range of load currents are obtained. The LTC1698 provides accurate secondary-side current limit using an external current sense resistor. The input voltage at the MARGIN pin provides ±5% output voltage adjustment. A power good flag and overvoltage input are provided to ensure proper power supply conditions. An auxiliary 3.3V logic supply is included that supplies up to 10mA of output current.

• High Efficiency Over Wide Load Current Range
• ±0.8% Output Voltage Accuracy
• Dual N-Channel MOSFET Synchronous Drivers
• Pulse Transformer Synchronization Optocoupler Feedback Driver
• Programmable Current Limit Protection
• ±5% Margin Output Voltage Adjustment
• Adjustable Overvoltage Fault Protection
• Power Good Flag
• Auxiliary 3.3V Logic Supply
• Available in 16-Lead SSOP and SO Packages

• 48V Input Isolated DC/DC Converters
• Isolated Telecommunication Power Systems
• Distributed Power Step-Down Converters
• Industrial Control Systems
• Automotive and Heavy Equipment