Alternative Parts

  • LTC3861
    LTC3861

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

Overview

Features and Benefits

  • Operates with Power Blocks, DrMOS or External Gate Drivers and MOSFETs
  • Voltage Mode Control with Accurate Current Sharing
  • ±0.75% 0.6V Voltage Reference
  • Quad Differential Output Voltage Sense Amplifiers
  • Multiphase Capability
  • Phase-Lockable Fixed Frequency 250kHz to 2.25MHz
  • Lossless Current Sensing Using Inductor DCR or Precision Current Sensing with Sense Resistor or DrMOS with Integrated Current Sensing
  • VCC Range: 3V to 5.5V
  • VOUT Range: 0.6V to VCC – 0.5V
  • Power Good Output Voltage Monitor
  • Output Voltage Tracking Capability with Soft-Start
  • Available in 58-Lead 5mm × 9mm QFN Package

Product Details

The LTC7851/LTC7851-1 are quad output multiphase synchronous step-down switching regulator controllers that employ a constant frequency voltage mode architecture. They maintain excellent current balance between channels when paralleled with their internal current sharing loop. Lossless DCR or a low value RSENSE is used for output current sensing. Multiple LTC7851/LTC7851-1 devices can be used for high phase count operation.

A very low offset, high bandwidth error amplifier, combined with remote output voltage sensing, provides excellent transient response and output regulation. The LTC7851/ LTC7851-1 operates with a VCC supply voltage from 3V to 5.5V and is designed for step-down conversion with VIN from 3V to 27V and produces an output voltage from 0.6V to VCC – 0.5V.

The LTC7851-1 is identical to the LTC7851 except it has a lower current sense amplifier gain, making it ideal for DrMOS devices with internal current sense.

Applications

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

Product Lifecycle icon-recommended Production

At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.

Evaluation Kits (3)

Tools & Simulations

LTspice

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.

To launch ready-to-run LTspice demonstration circuits for this part:

Step 1: Download and install LTspice on your computer.

Step 2: Click on the link in the section below to download a demonstration circuit.

Step 3: If LTspice does not automatically open after clicking the link below, you can instead run the simulation by right clicking on the link and selecting “Save Target As.” After saving the file to your computer, start LTspice and open the demonstration circuit by selecting ‘Open’ from the ‘File’ menu.

LTspice

Models for the following parts are available in LTspice:

LTC7851
LTC7851-1

LTpowerCAD

LTpowerCAD® is a power supply design program which selects power stage components, provides detailed power efficiency, shows quick loop Bode plot stability and load transient analysis, and can export to LTspice for simulation.

To open the project file for this circuit:

Step 1: Download and install LTpowerCAD on your computer.

Step 2: Click on the link(s) in the section below to download part-specific project files.

Step 3: If the project file doesn't run, right-click the link and select "Save Target As." Then start the LTpowerCAD tool and open the project file by selecing "Open Project" from the "File" menu.

LTPowerCAD

Design tools for the following parts are available in LTpowerCAD:

LTC7851
LTC7851 Parallel
LTC7851-1
LTC7851-1 Parallel
ltc7851-1Parallel
ltc7851Parallel

Product Recommendations

LTC7851 Companion Parts

Recommended Related Parts

Design Resources

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.

Discussions

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The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.


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Evaluation Boards Pricing displayed is based on 1-piece.
Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.