LTC3618

LTC3618 Dual 4MHz, ±3A Synchronous Buck Converter for DDR Termination Features n DDR Power Supply, Termination and Reference n High Efficiency: Up to 94% n Dual Outputs with ±3A Output Current Capability n 2.25V to 5.5V Input Voltage Range n ±1% Output Voltage Accuracy n VTT Output Voltage Down to 0.5V n Shutdown Current ≤1µA n VTTR = VDDQIN/2, VFB2 = VTTR n Adjustable Switching Frequency Up to 4MHz n Internal or External Compensation n Selectable 0°/90°/180° Phase Shift Between Channels n Internal or External Soft-Start for VDDQ, Internal Soft-Start for VTT n Power Good Status Outputs n Low Profile 4mm × 4mm QFN-24 and TSSOP-24 Packages Applications n DDR Memory n Supports DDR, DDR2, and DDR3 Standards n Tracking Supplies Description The LTC®3618 is a dual synchronous step-down regulator using a current mode, constant-frequency architecture. It provides a complete DDR solution with an input voltage range from 2.25V to 5.5V. The output of the first step-down regulator offers a high accuracy VDDQ supply. A buffered reference generates VTTR at 50% of VDDQIN and drives loads up to ±10mA. The second regulator generates the DDR termination voltage (VTT) equal to VTTR. Both regulators are capable of delivering ±3A of load current at 1MHz switching frequency. The operating frequency is externally programmable up to 4MHz, allowing the use of small surface mount inductors. 0°, 90°, or 180° of phase shift between the two channels can be selected to minimize input current ripple. For...