LTC3718 Datasheet | Linear Technology

Low Input Voltage DC/DC Controller for DDR/QDR Memory Termination Features s Very Low VIN(MIN): 1.5V s Ultrafast Transient Response s True Current Mode Control s 5V Drive for N-Channel MOSFETs Eliminates Auxillary 5V Supply s No Sense Resistor Required s Uses Standard 5V Logic-Level N-Channel MOSFETs s VOUT(MIN): 0.4V s VOUT Tracks 1/2 VIN or External VREF s Symmetrical Source and Sink Output Current Limit s Adjustable Switching Frequency s t ON(MIN) <100ns s Power Good Output Voltage Monitor s Programmable Soft-Start s Output Overvoltage Protection s Optional Short-Circuit Shutdown Timer s Small 24-Lead SSOP Package U APPLICATIO S s Bus Termination: DDR/QDR Memory, SSTL, HSTL, ... s Servers, RAID Systems s Distributed Power Systems s Synchronous Buck with General Purpose Boost DESCRIPTIO The LTC®3718 is a high current, high efficiency synchronous switching regulator controller for DDR and QDRTM memory termination. It operates from an input as low as 1.5V and provides a regulated output voltage equal to (0.5)VIN. The controller uses a valley current control architecture to enable high frequency operation with very low on-times without requiring a sense resistor. Operating frequency is selected by an external resistor and is pensated for variations in VIN and VOUT. The LTC3718 uses a pair of standard 5V logic level N-channel external MOSFETs, eliminating the need for expensive P-channel or low threshold devices. Forced continuous operation reduces noise and RF interference. Fault protection is provided by internal foldback current limiting, an output overvoltage parator and an optional short-circuit timer. Soft-start capability for supply sequencing can be acplished using an external timing capacitor. OPTI-LOOP® pensation allows the transient response to be optimized over a wide range of loads and output capacitors. , LTC and LT are registered trademarks of Linear Technology Corporation. OPTI-LOOP is a registered trademark of Linear...