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  4. Step-Down (Buck) Regulators
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  6. LTC3649

Data Sheet
PDF
JP
User Guides
2 View All

Alternative Parts

LTC3623
LTC3623

15V, ±5A Rail-to-Rail Synchronous Buck Regulator

LTC7149
LTC7149

60V, 4A Synchronous Step-Down Regulator for Inverting Outputs

Overview

Features and Benefits

  • Wide VIN Range: 3.1V to 60V
  • Wide VOUT Range: 0V to (VIN – 0.5V)
  • Single Resistor VOUT Programming
  • Integrated 110mΩ Top N-Channel/50mΩ Bottom N-Channel MOSFETs
  • 95% Efficiency with 12VIN and 5VOUT
  • Regulated IQ: 440μA, Shutdown IQ: 18μA
  • Accurate Current Monitoring (±4%) without Sense Resistor
  • Accurate Resistor Programmable Frequency (300kHz to 3MHz) with ±50% Frequency Sync Range
  • Accurate Programmable Output Current
  • Input Voltage Regulation for MPPT Applications
  • ±0.8% Output Voltage Accuracy
  • Peak Current Mode Operation
  • Programmable Wire Drop Compensation
  • Burst Mode® Operation, Forced Continuous Mode
  • Internal Compensation and Programmable Soft-Start
  • Overtemperature Protection
  • Available in Thermally Enhanced 28-Lead (4mm × 5mm) QFN and TSSOP Packages

Product Details

The LTC3649 is a high efficiency 60V, 4A synchronous monolithic step-down regulator. The regulator features a single resistor programmable output voltage, internal compensation and high efficiencies over a wide VOUT range.

The step-down regulator operates from an input voltage range of 3.1V to 60V and provides an adjustable rail-to-rail output range from (VIN – 0.5V) to ground while delivering up to 4A of output current. The switching frequency is also adjusted with an external resistor. A user-selectable mode input is provided to allow the user to trade off ripple noise for efficiency at light loads; Burst Mode operation provides the highest efficiency at light loads, while forced continuous mode provides low output ripple. The MODE/SYNC pin can also be used to allow the user to synchronize the switching frequency to an external clock.

The LTC3649 operates with a peak current mode architecture that allows for fast transient response with inherent cycle-to-cycle current limit protection. It also features programmable output current limit, current monitoring and input voltage regulation.

Applications

  • Industrial Applications
  • Automotive Applications

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Product Lifecycle icon-recommended Recommended for New Designs

This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.

Evaluation Kits (2)

Documentation & Resources

  • View All (11)
  • Data Sheets (1)
  • Reliability Data (1)
  • User Guides (2)
  • Demo Board Schematic (1)
  • Design Notes (3)
  • Videos (2)
  • Technical Articles (1)
    • Document Type

    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

    LTspice Simulations

    LTC3649 Demo Circuit - High Voltage Synchronous Buck Regulator with Output Voltage Control (10-60V to 5V @ 4A)
    LTC3649 Demo Circuit - High Voltage Monolithic Synchronous Buck Regulator with Output Voltage Control (10-60V to 2.5-7.5V @ 4A)
    LTC3649 Demo Circuit - Hold-Up Circuit Using a Buck Regulator with Vin Boost Capabilities (5.5-60V to 5V @ 4A, 8V Hold-Up)
    LTC3649 Demo Circuit - High Voltage Monolothic Synchronous Buck Regulator with Cable Drop Compensation (4-60V to 5V @ 4A)
    LTC3649 Demo Circuit - High Voltage Monolothic Synchronous Buck Regulator (4-60V to 5V @ 4A)

    Models for the following parts are available in LTspice:

    LTC3649

    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

    LTpowerCAD Project Files

    LTC3649 Project - 60V, 4A Synchronous Step-Down Regulator with Rail-to-Rail Programmable Output (4-60V to 3.3V @ 4A)

    Design tools for the following parts are available in LTpowerCAD:

    LTC3649

    Product Recommendations

    LTC3649 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.View our quality and reliability program and certifications for more information.

    Part Number Material Declaration Reliability Data Pin/Package Drawing CAD Symbols, Footprints & 3D Models
    LTC3649EFE#PBF Material Declaration Reliability Data 28-Lead TSSOP w/ EP
    LTC3649EFE#TRPBF Material Declaration Reliability Data 28-Lead TSSOP w/ EP
    LTC3649EUFD#PBF Material Declaration Reliability Data 28-Lead QFN (4mm x 5mm x 0.75mm w/ EP)
    LTC3649EUFD#TRPBF Material Declaration Reliability Data 28-Lead QFN (4mm x 5mm x 0.75mm w/ EP)
    LTC3649IFE#PBF Material Declaration Reliability Data 28-Lead TSSOP w/ EP
    LTC3649IFE#TRPBF Material Declaration Reliability Data 28-Lead TSSOP w/ EP
    LTC3649IUFD#PBF Material Declaration Reliability Data 28-Lead QFN (4mm x 5mm x 0.75mm w/ EP)
    LTC3649IUFD#TRPBF Material Declaration Reliability Data 28-Lead QFN (4mm x 5mm x 0.75mm w/ EP)
    Wafer Fabrication Data R526 Reliability Data

    PCN-PDN Information

    Select a model from the dropdown below to subscribe to PCN/PDN notifications and view past notifications as well.

    Select Model for PCN Information
    • LTC3649EFE#PBF Production
    • LTC3649EFE#TRPBF Production
    • LTC3649EUFD#PBF Production
    • LTC3649EUFD#TRPBF Production
    • LTC3649IFE#PBF Production
    • LTC3649IFE#TRPBF Production
    • LTC3649IUFD#PBF Production
    • LTC3649IUFD#TRPBF Production

    Support & Discussions

    LTC3649 Discussions

    RE: LTC3649 Top and bottom switch gate charge
    RE: LTC3649 datasheet circuit fails when powered with load
    All LTC3649 Discussions
    LTC3649 Contact ADI Technical Support »
    LTC3649 Ask your question »
    LTC3649 Contact ADI Technical Support » LTC3649 Ask your question »

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