LT3837 Datasheet | Linear Technology

LT3837 Isolated No-Opto Synchronous Flyback Controller Features Senses Output Voltage Directly from Primary Side Winding- No Optoisolator Required n Synchronous Driver for High Efficiency n Supply Voltage Range 4.5V to 20V n Accurate Regulation Without User Trims n Programmable Switching Frequency from 50k Hz to 250k Hz .. n Synchronizable n Load pensation n Undervoltage Lockout n Available in a Thermally Enhanced 16-Lead TSSOP Package n DESCRIPTION The LT®3837 is an isolated switching regulator controller designed for medium power flyback topologies. A typical application is 10W to 60W with the part powered from a DC supply. The LT3837 is a current mode controller that regulates an output voltage based on sensing the secondary voltage via a transformer winding during flyback. This allows for tight output regulation without the use of an optoisolator, improving dynamic response and reliability. Synchronous rectification increases converter efficiency and improves output cross regulation in multiple output converters. The LT3837 operates in forced continuous conduction mode which improves cross regulation in multiple winding applications. Switching frequency is user programmable and can be externally synchronized. The part also has load pensation, undervoltage lockout and soft-start circuitry. The LT3837 is available in a thermally enhanced 16-pin TSSOP package. APPLICATIONS n n n Isolated Medium Power (10W to 60W) Supplies Instrumentation Power Supplies Isolated Medical Supplies , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents including 6498466, 5841643. TYPICAL APPLICATION 9V - 18V to 3.3V at 10A Isolated Converter VIN 22.1k 10μF BAS16 2N3906 22μF VCC FB 3k 20k 3.3n F 100k 150k 12k PGDLY 1.37k 0.1μF RCMP CCMP GND SENSE- SG 330Ω VC 1n F 47p F OSC SFST t ON ENDLY Si7336ADP PG SENSE + Efficiency vs Load Current 90 88 86 EFFICIENCY...