LTC3900 Datasheet | Linear Technology

Synchronous Rectifier Driver for Forward Converters Features n N-Channel Synchronous Rectifier MOSFET Driver n Programmable Timeout Protection n Reverse Inductor Current Protection n Pulse Transformer Synchronization n Wide VCC Supply Range: 4.5V to 11V n 15ns Rise/Fall Times at VCC = 5V, CL = 4700p F n Undervoltage Lockout n Small SO-8 Package Applications n 48V Input Isolated DC/DC Converters n Isolated Tele Power Supplies n High Voltage Distributed Power Step-Down Converters n Industrial Control System Power Supplies n Automotive and Heavy Equipment Description The LTC®3900 is a secondary-side synchronous rectifier driver designed to be used in isolated forward converter power supplies. The chip drives N-channel rectifier MOSFETs and accepts pulse sychronization from the primary-side controller via a pulse transformer. The LTC3900 incorporates a full range of protection for the external MOSFETs. A programmable timeout function is included that disables both drivers when the synchronization signal is missing or incorrect. Additionally, the chip senses the output inductor current through the drain-source resistance of the catch MOSFET, shutting off the MOSFET if the inductor current reverses. The LTC3900 also shuts off the drivers if the supply voltage is too low. L, LT, LTC, LTM, Linear Technology, Burst Mode and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Typical Application VIN 36V TO 72V ISOLATION BARRIER T1 GATE Q1 Q3 470Ω ISENSE LT1952 10mΩ SOUT GND P SG T2 L0 D3 + COUT RCS2 RCS1 CS+ Q4 RCS3 CS-...