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LTC3811 - High Speed Dual, Multiphase Step-Down DC/DC Controller

The LTC3811 is a dual, PolyPhase synchronous step- down switching regulator controller optimized for output voltages up to 3.3V. The LTC3811 includes high bandwidth error amplifiers as well as a high speed differential remote sense amplifier. The sense voltage range is programmable from 24mV to 85mV, allowing the use of either the inductor DCR or a discrete sense resistor. Multiphase operation is made possible using the MODE/SYNC input, the CLKOUT output and the PHASEMODE control pin, allowing 1-, 2-, 3-, 4-, 6- or 12-phase operation. Large internal gate drivers minimize switching losses and allow the use of multiple power MOSFETs connected in parallel for high current applications. The operating frequency of the LTC3811 can be programmed from 250kHz to 750kHz and can also be synchronized to an external clock using the internal PLL.

Tracking and sequencing are possible with the LTC3811, and soft-start is programmed with an external capacitor. Shutdown reduces supply current to 20µA.

Features Fixed Frequency, Peak Current Mode Control ±0.5% Output Accuracy Over Temperature Optimized for Low VOUT Applications (Up to 3.3V) Dual or Single Output, Multiphase Operation Wide VIN Range: 4.5V to 30V Operation High Speed Differential Remote Sense Amplifier Inductor DCR or Sense Resistor Capable Adjustable Peak Current Sense Voltage: 24mV to 85mV Very Low Duty Cycle Operation: tON(MIN) = 65ns (Typ) Powerful Internal Gate Drivers Output Voltage Soft-Start, Tracking and Sequencing Programmable Load Line for Reduced COUT Clock Input and Output for Up to 12-Phase Operation Fixed Frequency Operation from 250kHz to 750kHz PLL Synchronization from 150kHz Up to 900kHz Selectable CCM or DCM Operation Available in 5mm x 7mm QFN and G36 Packages Typical Application

Applications Network Servers High Current ASIC Supplies Low Voltage Power Distribution Packaging

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