LTC1435 Datasheet | Linear Technology

LTC1435 High Efficiency Low Noise Synchronous Step-Down Switching Regulator Features s s s s s s s s s s s s DESCRIPTION The LTC®1435 is a synchronous step-down switching regulator controller that drives external N-channel power MOSFETs using a fixed frequency architecture. Burst Mode TM operation provides high efficiency at low load currents. A maximum duty cycle limit of 99% provides low dropout operation which extends operating time in battery-operated systems. The operating frequency is set by an external capacitor allowing maximum flexibility in optimizing efficiency. A secondary winding feedback control pin, SFB, guarantees regulation regardless of load on the main output by forcing continuous operation. Burst Mode operation is inhibited when the SFB pin is pulled low which reduces noise and RF interference. Soft start is provided by an external capacitor which can be used to properly sequence supplies. The operating current level is user-programmable via an external current sense resistor. Wide input supply range allows operation from 3.5V to 30V (36V maximum). , LTC and LT are registered trademarks of Linear Technology Corporation. Burst Mode is a trademark of Linear Technology Corporation. s s U APPLICATIONS s s s s s Dual N-Channel MOSFET Synchronous Drive Programmable Fixed Frequency Wide VIN Range: 3.5V to 36V Operation Ultrahigh Efficiency Very Low Dropout Operation: 99% Duty Cycle Low Standby Current Secondary Feedback Control Programmable Soft Start Remote Output Voltage Sense Logic Controlled Micropower Shutdown: IQ < 25µA Foldback Current Limiting (Optional) Current Mode Operation for Excellent Line and Load Transient Response Output Voltages from 1.19V to 9V Available in 16-Lead Narrow SO and SSOP Packages Notebook and Palmtop puters, PDAs Cellular Telephones and Wireless Modems Portable Instruments Battery-Operated Devices DC Power Distribution Systems TYPICAL APPLICATION COSC 68p F COSC CSS 0.1µF CC 330p F RC 10k SGND 100p F VOSENSE SENSE -...