LT3748 100V Isolated Flyback Controller Features Description n 5V to 100V Input Voltage Range The LT 3748 is a switching regulator controller specifically n 1.9A Average Gate Drive Source and Sink Current designed for the isolated flyback topology and capable of n Boundary Mode Operation high power. It drives a low side external N-channel power n No Transformer Third Winding or Opto-Isolator MOSFET from an internally regulated 7V supply. No third winding or opto-isolator is required for regulation as the Required for Regulation n part senses the isolated output voltage directly from the Primary-Side Winding Feedback Load Regulation n primary-side flyback waveform. V Set with Two External Resistors OUT n INTV Pin for Control of Gate Driver Voltage CC The LT3748 utilizes boundary mode to provide a small n Programmable Soft Start magnetic solution without compromising load regulation. n Programmable Undervoltage Lockout Operating frequency is set by load current and transformer n Available in MSOP Package magnetizing inductance. The gate drive of the LT3748 combined with a suitable external MOSFET allow it to deliver load power up to several tens of watts from input a voltages as high as 100V. n Isolated Telecom Converters The LT3748 is available in a high voltage 16-lead MSOP n High Power Automotive Supplies package with four leads removed. n Isolated Industrial Power Supplies L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear n Military and High Temperature Applications Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents, including 5438499 and 7471522. t a 25W, 12V Output, Isolated Telecom Supply Output Load and Line Regulation + V OUT 4:1 V 12.6 IN 12V 36V TO 72V 2A 10F 412k 12.4 100F 60.8H 3.8H V IN EN/UVLO 243k V R 15.4k OUT 12.2 FB R REF 12.0 6.04k LT3748 11.8 TC GATE V = 72V IN 11.6 SS SENSE V = 48V IN V = 36V V GND INTV IN C CC 0.033 11.4 0 0.5 1.0 1.5 2.0 56.2k 2nF 10k 3748 TA01a LOAD CURRENT (A) 4700pF 4.7F 3748 TA01b 3748fb 1 For more information www.linear.com/LT3748 V (V) OUT pplication ypical pplicationsLT3748 a Maxi Mu M r p c F (Note 1) TOP VIEW V , R ...................................................................100V IN FB V 1 16 R IN FB V to R ..................................................................5V IN FB EN/UVLO 3 14 R REF EN/UVLO ......................................................0.3V, 100V INTV 5 12 TC CC INTV ....................................................V + 0.3V, 20V CC IN GATE 6 11 V C SENSE 7 10 SS SS, V , TC, R ..........................................................6V C REF GND 8 9 GND SENSE ......................................................................0.4V MS PACKAGE 16 (12)-LEAD PLASTIC MSOP Operating Junction Temperature Range (Note 2) T = 150C, = 90C/W JMAX JA LT3748E/LT3748I ............................... 40C to 125C LT3748H ............................................ 40C to 150C LT3748MP ......................................... 55C to 150C Storage Temperature Range ..................65C to 150C D F M LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT3748EMS PBF LT3748EMS TRPBF 3748 16-Lead Plastic MSOP 40C to 125C LT3748IMS PBF LT3748IMS TRPBF 3748 16-Lead Plastic MSOP 40C to 125C LT3748HMS PBF LT3748HMS TRPBF 3748 16-Lead Plastic MSOP 40C to 150C LT3748MPMS PBF LT3748MPMS TRPBF 3748 16-Lead Plastic MSOP 55C to 150C Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. For more information on lead free part marking, go to: