LTC3736-2 Datasheet | Linear Technology

Features n No Current Sense Resistors Required n Out-of-Phase Controllers Reduce Required Input Capacitance n Tracking Function n Wide VIN Range: 2.75V to 9.8V n 0.6V ±1% Voltage Reference n High Current Limit n Constant-Frequency Current Mode Operation n Low Dropout Operation: 100% Duty Cycle n True PLL for Frequency Locking or Adjustment n Selectable Pulse-Skipping/Forced Continuous Operation n Auxiliary Winding Regulation n Internal Soft-Start Circuitry n Power Good Output Voltage Monitor n Output Overvoltage Protection n Micropower Shutdown: IQ = 9μA n Tiny Low Profile (4mm × 4mm) QFN and Narrow SSOP Packages APPLICATIONS n One or Two Lithium-Ion Powered Devices n Notebook and Palmtop puters, PDAs n Portable Instruments n Distributed DC Power Systems Dual 2-Phase, No RSENSETM, Synchronous Controller with Output Tracking DESCRIPTION The LTC®3736-2 is a 2-phase dual synchronous step-down switching regulator controller with tracking that drives external plementary power MOSFETs using few external ponents. The constant-frequency current mode architecture with MOSFET VDS sensing eliminates the need for sense resistors and improves efficiency. Power loss and noise due to the ESR of the input capacitance are minimized by operating the two controllers out-of-phase. Pulse-skipping operation provides high efficiency at light loads. 100% duty cycle capability provides low dropout operation, extending operating time in battery-powered systems. The switching frequency can be programmed up to 750k Hz, allowing the use of small surface mount inductors and capacitors. For noise sensitive applications, the LTC3736-2 switching frequency can be externally synchronized from 250k Hz to 850k Hz. An internal soft-start, which can be lengthened externally, smoothly ramps the output voltage during start-up. The LTC3736-2 is available in the tiny thermally enhanced (4mm × 4mm) QFN and 24-lead narrow SSOP packages. , LT, LTC and LTM are registered trademarks of Linear...