LTC3861-1

RECOMMENDED FOR NEW DESIGNS

Dual, Multiphase Step-Down Voltage Mode DC/DC Controller with Accurate Current Sharing

Part Models: 4
1ku List Price: Starting From $3.32

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Overview

Operates with Power Blocks, DrMOS or External Gate Drivers and MOSFETs
Constant-Frequency Voltage Mode Control with Accurate Current Sharing
±0.75% 0.6V Voltage Reference
Differential Remote Output Voltage Sense Amplifier
Multiphase Capability—Up to 12-Phase Operation
Programmable Current Limit
Safely Powers a Prebiased Load
Programmable or PLL-Synchronizable Switching Frequency Up to 2.25MHz

Lossless Current Sensing Using Inductor DCR or Precision Current Sensing with Sense Resistor
V_CC Range: 3V to 5.5V
V_IN Range: 3V to 24V
Power Good Output Voltage Monitor
Output Voltage Tracking Capability
Programmable Soft-Start
Available in a 32-Pin 5mm × 5mm QFN Package

The LTC3861-1 is a dual PolyPhase^® synchronous stepdown switching regulator controller for high current distributed power systems, digital signal processors, and other telecom and industrial DC/DC power supplies. It uses a constant-frequency voltage mode architecture combined with very low offset, high bandwidth error amplifiers and a remote output sense differential amplifier for excellent transient response and output regulation.

The controller incorporates lossless inductor DCR current sensing to maintain current balance between phases and to provide overcurrent protection. The chip operates from a V_CC supply between 3V and 5.5V and is designed for stepdown conversion from V_IN between 3V and 24V to output voltages between 0.6V and V_CC – 0.5V.

Inductor current reversal is disabled during soft-start to safely power prebiased loads. The constant operating frequency can be synchronized to an external clock or linearly programmed from 250kHz to 2.25MHz. Up to six LTC3861-1 controllers can operate in parallel for 1-, 2-, 3-, 4-, 6- or 12-phase operation.

The LTC3861-1 is pin-to-pin compatible with the LTC3860. It is available in a 32-pin 5mm × 5mm QFN package. The LTC3861is a 36-pin QFN version of the LTC3861-1, which has dual differential output voltage sense amplifiers.


	# Diff Amps	Config Pin	Package
LTC3861	2	Yes	5 x 6 QFN-36
LTC3861-1	1	No	5 x 5 QFN-32

Applications

High Current Distributed Power Systems
DSP, FPGA and ASIC Supplies
Datacom and Telecom Systems
Industrial Power Supplies

Part Models: 4
1ku List Price: Starting From $3.32

Documentation

ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal. View our quality and reliability program and certifications for more information.

Part Model	Pin/Package Drawing	Documentation	CAD Symbols, Footprints, and 3D Models
LTC3861EUH-1#PBF	32-Lead QFN (5mm x 5mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3861EUH-1#TRPBF	32-Lead QFN (5mm x 5mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3861IUH-1#PBF	32-Lead QFN (5mm x 5mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3861IUH-1#TRPBF	32-Lead QFN (5mm x 5mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys

Part Models	Product Lifecycle	PCN

Jan 20, 2022 - 21_0269 Addition of Alternate Assembly Site ASE Taiwan for Select LFCSP Products
		PCN21_0269_Form Material_Report Detailed Change Description Qualification Results Summary
LTC3861EUH-1#PBF	PRODUCTION
LTC3861EUH-1#TRPBF	PRODUCTION
LTC3861IUH-1#PBF	PRODUCTION
LTC3861IUH-1#TRPBF	PRODUCTION

This is the most up-to-date revision of the Data Sheet.

Software Resources

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Hardware Ecosystem

Parts	Product Life Cycle	Description
Circuit Monitors 1
LTC2960	RECOMMENDED FOR NEW DESIGNS	36V Nano-Current Two-Input Voltage Monitor
Power System Management (PSM) & Sequencers 1
LTC2974	RECOMMENDED FOR NEW DESIGNS	4-Channel PMBus Power System Manager Featuring Accurate Output Current Measurement
Protection Switches & Controllers 1
LT4363	RECOMMENDED FOR NEW DESIGNS	High Voltage Surge Stopper with Current Limit
Switching Regulators & Controllers 1
LTC3880	RECOMMENDED FOR NEW DESIGNS	Dual Output PolyPhase Step-Down DC/DC Controller with Digital Power System Management

Parts	Product Life Cycle	Description
LTC3861	RECOMMENDED FOR NEW DESIGNS	Dual, Multiphase Step-Down Voltage Mode DC/DC Controller with Accurate Current Sharing

Tools & Simulations

LTspice

Models for the following parts are available in LTspice:

LTC3861
LTC3861-1

LTpowerCAD

Design tools for the following parts are available in LTpowerCAD:

LTC3861

LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.

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