LTC3805 Datasheet | Linear Technology

Features n VIN and VOUT Limited Only by External ponents n Adjustable Slope pensation n Adjustable Overcurrent Protection with Automatic Restart n Adjustable Operating Frequency (70k Hz to 700k Hz) with One External Resistor n Synchronizable to an External Clock n ±1.5% Reference Accuracy n Current Mode Operation for Excellent Line and Load Transient Response n RUN Pin with Precision Threshold and Adjustable Hysteresis n Programmable Soft-Start with One External Capacitor n Low Quiescent Current: 360µA n Small 10-Lead MSOP and 3mm × 3mm DFN Applications n Tele Power Supplies n 42V and 12V Automotive Power Supplies n Isolated Electronic Equipment Adjustable Frequency Current Mode Flyback DC/DC Controller Description The LTC®3805 is a current mode controller for flyback DC/DC converters designed to drive an N-channel MOSFET in high input and output voltage converter applications. Operating frequency and slope pensation can be programmed by external resistors. Programmable overcurrent sensing protects the converter from short-circuits. Soft-start can be programmed using an external capacitor and the soft-start capacitor also programs an automatic restart feature. The LTC3805 provides ±1.5% output voltage accuracy and consumes only 360µA of quiescent current during normal operation and only 40µA during micropower startup. Using a 9.5V internal shunt regulator, the LTC3805 can be powered from a high VIN through a resistor or it can be powered directly from a low impedance DC voltage of 9V or less. The LTC3805 is available in the 10-lead MSOP package and the 3mm × 3mm DFN package. L,LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks, No RSENSE and Thin SOT are trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Typical Application 36V - 72V to 5V/2A Nonisolated Flyback Converter 36V TO 72V 2.2µF ×2 221k 100k 8.66k 20k 470p...