LTC3856 Series

2-Phase Synchronous Step-Down DC/DC Controller with Diffamp

Catalog

2-Phase Synchronous Step-Down DC/DC Controller with Diffamp

Part	Function	Output Configuration	Mounting Type	Duty Cycle (Max) [Max]	Frequency - Switching [Max]	Frequency - Switching [Min]	Voltage - Supply (Vcc/Vdd) [Max]	Voltage - Supply (Vcc/Vdd) [Min]	Supplier Device Package	Control Features	Number of Outputs	Output Phases	Topology	Output Type	Operating Temperature [Min]	Operating Temperature [Max]	Package / Case
Analog Devices LTC3856IUH#PBF	Step-Down	Positive	Surface Mount	94 %	770 kHz	250 kHz	38 V	4.5 V	32-QFN (5x5)	Current Limit Enable Frequency Control Phase Control Power Good Soft Start Tracking	2	2	Buck	Transistor Driver	-40 °C	125 ¯C
Analog Devices LTC3856EUH#PBF	Step-Down	Positive	Surface Mount	94 %	770 kHz	250 kHz	38 V	4.5 V	32-QFN (5x5)	Current Limit Enable Frequency Control Phase Control Power Good Soft Start Tracking	2	2	Buck	Transistor Driver	-40 °C	125 ¯C
Analog Devices LTC3856EFE#TRPBF	Step-Down	Positive	Surface Mount	94 %	770 kHz	250 kHz	38 V	4.5 V	38-TSSOP-EP	Current Limit Enable Frequency Control Phase Control Power Good Soft Start Tracking	2	2	Buck	Transistor Driver	-40 °C	125 ¯C	38-TFSOP

Catalog

2-Phase Synchronous Step-Down DC/DC Controller with Diffamp

Key Features

• PolyPhase®Controller Reduces Input and Output Capacitance and Power Supply Induced Noise

• Wide VINRange: 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)

• RSENSEor 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

• VOUTRange: 0.6V to 5V without Differential Amplifier

• VOUTRange: 0.6V to 3.3V with Differential Amplifier

• Adjustable Soft-Start or VOUTTracking

• Stackable for Up to 12-Phase Operation

• 32-Pin (5mm × 5mm) QFN and 38-Pin TSSOP Packages

Description

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.ApplicationsTelecom and Datacom SystemsIndustrial and Medical InstrumentsDC Power Distribution SystemsComputer Systems