LTC3809-1 Datasheet | Linear Technology

No RSENSETM, Low Input Voltage, Synchronous DC/DC Controller with Output Tracking Features n Programmable Output Voltage Tracking n No Current Sense Resistor Required n Constant Frequency Current Mode Operation for Excellent Line and Load Transient Response n Wide VIN Range: 2.75V to 9.8V n Wide VOUT Range: 0.6V to VIN n 0.6V ±1.5% Reference n Low Dropout Operation: 100% Duty Cycle n Selectable Burst Mode®/Pulse-Skipping/Forced Continuous Operation n Auxiliary Winding Regulation n Internal Soft-Start Circuitry n Selectable Maximum Peak Current Sense Threshold n Output Overvoltage Protection n Micropower Shutdown: IQ = 9μA n Tiny Thermally Enhanced Leadless (3mm × 3mm) DFN and 10-lead MSOP Packages APPLICATIONS n 1- or 2-Cell Lithium-Ion Powered Devices n Notebook and Palmtop puters, PDAs n Portable Instruments n Distributed DC Power Systems DESCRIPTION The LTC®3809-1 is a synchronous step-down switching regulator controller that drives external plementary power MOSFETs using few external ponents. The constant frequency current mode architecture with MOSFET VDS sensing eliminates the need for a current sense resistor and improves efficiency. Optional Burst Mode operation provides high efficiency operation at light loads. 100% duty cycle provides low dropout operation, extending operating time in batterypowered systems. Burst Mode is inhibited when the MODE pin is pulled low to reduce noise and RF interference. The LTC3809-1 allows either coincident or ratiometric output voltage tracking. Switching frequency is fixed at 550k Hz. Fault protection is provided by an overvoltage parator and a short-circuit current limit parator. The LTC3809-1 is available in tiny footprint thermally enhanced DFN and 10-lead MSOP packages. , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. Burst is a registered trademark of Linear Technology Corporation. No RSENSE is a trademark of Linear Technology Corporation. All other trademarks are...