Overview

Features and Benefits

  • Silent Switcher®2 Architecture
    • Ultralow EMI Emissions On Any PCB
    • Eliminates PCB Layout Sensitivity
    • Internal Bypass Capacitors Reduce Radiated EMI
    • Optional Spread Spectrum Modulation
  • High Efficiency at High Frequency
    • Up to 96% Efficiency at 1MHz, 12VIN to 3.3VOUT
    • Up to 95% Efficiency at 2MHz, 12VIN to 3.3VOUT
  • Wide Input Voltage Range: 2.8V to 18V
  • 10A Output Current
  • External Compensation: Fast Transient Response and Current Sharing
  • Low Quiescent Current Burst Mode® Operation
    • n 240µA IQ Regulating 12VIN to 1.2VOUT
    • Output Ripple < 10mVP-P
  • Fast Minimum Switch On-Time: 25ns
  • Low Dropout Under All Conditions: 50mV at 1A
  • Forced Continuous Mode
  • Adjustable and Synchronizable: 200kHz to 3MHz
  • Output Soft-Start and Power Good
  • Small 24-Lead 4mm × 4mm LQFN Package
  • Product Details

    The LT®8642S synchronous step-down regulator features second generation Silent Switcher architecture designed to minimize EMI emissions while delivering high efficiency at high switching frequencies. This includes the integration of bypass capacitors to optimize all the fast current loops inside and make it easy to achieve advertised EMI performance by eliminating layout sensitivity. This performance makes the LT8642S ideal for noise sensitive applications and environments.

    The fast, clean, low-overshoot switching edges enable high efficiency operation even at high switching frequencies, leading to a small overall solution size. Peak current mode control with a 25ns minimum on-time allows high step down ratios even at high switching frequencies. External compensation via the VC pin allows for fast transient response at high switching frequencies. The VC pin also enables current sharing and a CLKOUT pin enables synchronizing other regulators to the LT8642S.

    Burst Mode operation enables low standby current consumption, forced continuous mode can control frequency harmonics across the entire output load range, or spread spectrum operation can further reduce EMI emissions. Soft-start and tracking functionality is accessed via the SS pin, and an accurate input voltage UVLO threshold can be set using the EN/UV pin.

    APPLICATIONS

    • Server Power Applications
    • General Purpose Step-Down

    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 (1)

    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.

    LTspice

    Models for the following parts are available in LTspice:

    lt8642s

    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.

    LTPowerCAD

    Design tools for the following parts are available in LTpowerCAD:

    lt8642s

    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.

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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.