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  6. LTC1778/LTC1778-1

Data Sheet Rev. B
PDF
JP
User Guide
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Alternative Parts

LTC3878
LTC3878

Fast, Wide Operating Range No RSENSE Step-Down DC/DC Controller

Overview

Features and Benefits

  • No Sense Resistor Required
  • True Current Mode Control
  • Optimized for High Step-Down Ratios
  • tON(MIN) <=100ns
  • Extremely Fast Transient Response
  • Stable with Ceramic COUT
  • Dual N-Channel MOSFET Synchronous Drive
  • Power Good Output Voltage Monitor (LTC1778)
  • Adjustable On-Time (LTC1778-1)
  • Wide VIN Range: 4V to 36V
  • ±1% 0.8V Voltage Reference
  • Adjustable Current Limit
  • Adjustable Switching Frequency
  • Programmable Soft-Start
  • Output Overvoltage Protection
  • Optional Short-Circuit Shutdown Timer
  • Micropower Shutdown: IQ <30µA
  • Available in a 16-Pin Narrow SSOP Package

Product Details

The LTC1778 is a synchronous stepdown switching regulator controller optimized for CPU power. The controller uses a valley current control architecture to deliver very low duty cycles with excellent transient response without requiring a sense resistor. Operating frequency is selected by an external resistor and is compensated for variations in VIN.

Discontinuous mode operation provides high efficiency operation at light loads. A forced continuous control pin reduces noise and RF interference, and can assist secondary winding regulation by disabling discontinuous operation when the main output is lightly loaded.

Fault protection is provided by internal foldback current limiting, an output overvoltage comparator and optional short-circuit shutdown timer. Soft-start capability for supply sequencing is accomplished using an external timing capacitor. The regulator current limit level is user programmable. Wide supply range allows operation from 4V to 36V at the input and from 0.8V up to (0.9)VIN at the output.

Applications

  • Notebook and Palmtop Computers, PDAs
  • Distributed Power Systems

Product Categories

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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 (2)

Documentation & Resources

  • View All (11)
  • Data Sheet (1)
  • Reliability Data (1)
  • User Guide (2)
  • Design Note (3)
  • Technical Article (4)
    • 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

    LTC1778 Demo Circuit - No Rsense, Synchronous Step-Down Controller (12V to 2.5V @ 10A)

    Models for the following parts are available in LTspice:

    LTC1778
    LTC1778-1

    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
    LTC1778EGN#PBF Material Declaration Reliability Data 16-Lead SSOP (Narrow 0.15 Inch)
    LTC1778EGN#TRPBF Material Declaration Reliability Data 16-Lead SSOP (Narrow 0.15 Inch)
    LTC1778EGN-1#PBF Material Declaration Reliability Data 16-Lead SSOP (Narrow 0.15 Inch)
    LTC1778EGN-1#TRPBF Material Declaration Reliability Data 16-Lead SSOP (Narrow 0.15 Inch)
    LTC1778IGN#PBF Material Declaration Reliability Data 16-Lead SSOP (Narrow 0.15 Inch)
    LTC1778IGN#TRPBF Material Declaration Reliability Data 16-Lead SSOP (Narrow 0.15 Inch)
    Wafer Fabrication Data R384 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
    • LTC1778EGN#PBF Production
    • LTC1778EGN#TRPBF Production
    • LTC1778EGN-1#PBF Production
    • LTC1778EGN-1#TRPBF Production
    • LTC1778IGN#PBF Production
    • LTC1778IGN#TRPBF Production

    Support & Discussions

    LTC1778 Discussions

    RE: LTC1778 maximum inductor value
    All LTC1778 Discussions
    LTC1778 Contact ADI Technical Support »
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    LTC1778 Contact ADI Technical Support » LTC1778 Ask your question »

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    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.

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