LT3512 Monolithic High Voltage Isolated Flyback Converter FeaTuresDescripTion n 4.5V to 100V Input Voltage Range The LT3512 is a high voltage monolithic switching regula- n Internal 420mA, 150V Power Switch tor specifically designed for the isolated flyback topology. n Boundary Mode Operation No third winding or opto-isolator is required for regula- n No Transformer Third Winding or tion as the part senses output voltage directly from the Opto-Isolator Required for Regulation primary-side flyback waveform. The device integrates a n Improved Primary-Side Winding Feedback 420mA, 150V power switch, high voltage circuitry, and Load Regulation control into a high voltage 16-lead MSOP package with n VOUT Set with Two External Resistors four leads removed. n BIAS Pin for Internal Bias Supply and Power The LT3512 operates from an input voltage range of 4.5V Switch Driver to 100V and delivers up to 4.5W of isolated output power. n No External Start-Up Resistor Two external resistors and the transformer turns ratio n 16-Lead MSOP Package easily set the output voltage. Off-the-shelf transformers are available for several applications. The high level of applicaTions integration and the use of boundary mode operation results in a simple, clean, tightly regulated application solution to n Isolated Telecom Power Supplies the traditionally tough problem of isolated power delivery. n Isolated Auxiliary/Housekeeping Power Supplies L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks n Isolated Industrial, Automotive and Medical Power and No RSENSE is a trademark of Linear Technology Corporation. All other trademarks are the Supplies property of their respective owners. Protected by U.S. Patents, including 5438499, 7471522. Typical applicaTion48V to 5V Isolated Flyback ConverterOutput Load and Line Regulation VIN V + 5.25 36V TO 72V OUT 4:1 5V 1µF 1M 5.20 V 0.5A IN • EN/UVLO 5.15 175µH 11µH 47µF 43.2k • 5.10 V LT3512 169k V – IN = 48V VIN = 36V R OUT 5.05 FB R (V) REF 5.00 10k V OUT 4.95 VIN = 72V 4.90 TC SW 4.85 VC GND BIAS 4.80 57.6k 12.7k 4.75 0 100 200 300 400 500 4.7nF 4.7µF LOAD CURRENT (mA) 3512 TA01a 3512 TA01b 3512fb 1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts
