LT3575 Isolated Flyback Converter without an Opto-Coupler FEATURES DESCRIPTION n 3V to 40V Input Voltage Range The LT 3575 is a monolithic switching regulator speci c- n 2.5A, 60V Integrated NPN Power Switch ally designed for the isolated yback topology. No third n Boundary Mode Operation winding or optoisolator is required for regulation. The n No Transformer Third Winding or part senses the isolated output voltage directly from the Optoisolator Required for Regulation primary side yback waveform. A 2.5A, 60V NPN power n Improved Primary-Side Winding Feedback switch is integrated along with all control logic into a Load Regulation 16-lead TSSOP package. n V Set with Two External Resistors OUT The LT3575 operates with input supply voltages from n BIAS Pin for Internal Bias Supply and Power 3V to 40V, and can deliver output power up to 14W with NPN Driver no external power switch.The LT3575 utilizes boundary n Programmable Soft-Start mode operation to provide a small magnetic solution with n Programmable Power Switch Current Limit improved load regulation. n Thermally Enhanced 16-Lead TSSOP The output voltage is easily set with two external resistors and the transformer turns ratio. Off the shelf transformers APPLICATIONS are available for many applications. n Industrial, Automotive and Medical Isolated L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks and No RSENSE and ThinSOT is a trademark of Linear Technology Corporation. All other Power Supplies trademarks are the property of their respective owners. TYPICAL APPLICATION 5V Isolated Flyback Converter Load Regulation V IN 12V TO 24V 1 3:1 + V = 24V 10F 357k 0.22F1k V IN OUT V 5V, 1.4A IN SHDN/UVLO 24H 2.6H47F 0 51.1k V V = 12V OUT IN 80.6k R FB LT3575 R REF 1 TC 6.04k R ILIM SS SW VC GND TEST BIAS 2 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 28.7k 10k 11.5k I (A) OUT 3575 TA01b 4.7F 10nF 4.7nF 3575 TA01 3575f 1 OUTPUT VOLTAGE ERROR (%)LT3575 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION SW ............................................................................60V TOP VIEW V , SHDN/UVLO, R , BIAS .....................................40V IN FB 1 NC 16 NC SS, V , TC, R , R ..............................................5V C REF ILIM V 2 NC 15 IN Maximum Junction Temperature .......................... 125C SW 3 GND 14 Operating Junction Temperature Range (Note 2) SW 4 TEST 13 17 LT3575E, LT3575I .............................. 40C to 125C GND BIAS TC 5 12 Storage Temperature Range ..................65C to 150C SHDN/UVLO R 6 11 REF SS R 7 FB 10 R V ILIM 8 C 9 FE PACKAGE 16-LEAD PLASTIC TSSOP T = 125C, = 38C/W, = 10C/W JMAX JA JC EXPOSED PAD (PIN 17) IS GND, MUST BE CONNECTED TO GND ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT3575EFE PBF LT3575EFE TRPBF 3575FE 16-Lead Plastic TSSOP 40C to 125C LT3575IFE PBF LT3575IFE TRPBF 3575FE 16-Lead Plastic TSSOP 40C to 125C Consult LTC Marketing for parts speci ed with wider operating temperature ranges. *The temperature grade is identi ed by a label on the shipping container. For more information on lead free part marking, go to: