LT3748 Datasheet | Linear Technology

Features n n n n Description The LT®3748 is a switching regulator controller specifically designed for the isolated flyback topology and capable of high power. It drives a low side external N-channel power MOSFET from an internally regulated 7V supply. No third winding or opto-isolator is required for regulation as the part senses the isolated output voltage directly from the primary-side flyback waveform. The LT3748 utilizes boundary mode to provide a small magnetic solution without promising load regulation. Operating frequency is set by load current and transformer magnetizing inductance. The gate drive of the LT3748 bined with a suitable external MOSFET allow it to deliver load power up to several tens of watts from input voltages as high as 100V. The LT3748 is available in a high voltage 16-lead MSOP package with four leads removed. L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents, including 5438499 and 7471522. n n n n n n 5V to 100V Input Voltage Range 1.9A Average Gate Drive Source and Sink Current Boundary Mode Operation No Transformer Third Winding or Opto-Isolator Required for Regulation Primary-Side Winding Feedback Load Regulation VOUT Set with Two External Resistors INTVCC Pin for Control of Gate Driver Voltage Programmable Soft Start Programmable Undervoltage Lockout Available in MSOP Package Applications Isolated Tele Converters High Power Automotive Supplies n Isolated Industrial Power Supplies n n Typical Application 25W, 12V Output, Isolated Tele Supply VIN 36V TO 72V 10µF 412k EN/UVLO 15.4k VIN RFB RREF LT3748 TC SS VC 56.2k 2n F 10k 4700p F 4.7µF GND GATE SENSE INTVCC 0.033Ω 3748 TA01a 4:1 60.8µH 243k 3.8µH VOUT+ 12V 2A 100µF VOUT- Output Load and Line Regulation 12.6 14.4 12.2 VOUT (V) 12.0 11.8 11.6 11.4 VIN = 72V VIN = 48V VIN = 36V 0 0.5 1.0 1.5 LOAD CURRENT (A)...