LTC3856 Datasheet

• PolyPhase^® Controller Reduces Input and Output Capacitance and Power Supply Induced Noise
• Wide V_IN Range: 4.5V to 38V Operation
• ±0.75%, 0.6V Reference Voltage Accuracy
• High Efficiency: Up to 95%
• Programmable Burst Mode^® Operation or Stage Shedding^™ for Highest Light Load Efficiency
• Active Voltage Positioning (AVP)
• R_SENSE or DCR Current Sensing
• Programmable DCR Temperature Compensation
• Phase-Lockable Fixed Frequency: 250kHz to 770kHz
• True Remote Sense Differential Amplifier
• Dual N-Channel MOSFET Synchronous Drive
• V_OUT Range: 0.6V to 5V without Differential Amplifier
• V_OUT Range: 0.6V to 3.3V with Differential Amplifier
• Adjustable Soft-Start or V_OUT Tracking
• Stackable for Up to 12-Phase Operation
• 32-Pin (5mm × 5mm) QFN and 38-Pin TSSOP Packages

• Telecom and Datacom Systems
• Industrial and Medical Instruments
• DC Power Distribution Systems
• Computer Systems

The LTC3856 is a single output, dual channel PolyPhase synchronous step-down DC/DC controller that drives all N-channel power MOSFET stages. This device includes a high speed differential amplifier for remote output voltage sense. Power loss and supply noise are minimized by operating the two controller output stages out-of-phase and up to 12-phase operation can be achieved.

The LTC3856 monitors the output current by sensing the voltage drop across the output inductor (DCR) or by using a sense resistor. DCR temperature compensation maintains an accurate current sense threshold over a broad temperature range. A constant-frequency, current mode architecture allows a phase-lockable frequency of up to 770kHz.

A wide 4.5V to 38V input supply range encompasses most intermediate bus voltages and battery chemistries. Burst Mode operation, continuous or Stage Shedding modes are supported. A TK/SS pin shared by both channels ramps the output voltage during start-up.