Overview

Features and Benefits

  • Silent Switcher® Architecture
    • Ultralow EMI Emissions
    • Optional Spread Spectrum Modulation
  • High Efficiency at High Frequency
    • Up to 96% Efficiency at 1MHz, 12VIN to 5VOUT
    • Up to 95% Efficiency at 2MHz, 12VIN to 5VOUT
  • Wide Input Voltage Range: 3.4V to 42V
  • 6A Maximum Continuous, 7A Peak Output
  • Ultralow Quiescent Current Burst Mode® Operation
    • 2.5μA IQ Regulating 12VIN to 3.3VOUT (LT8640S-2)
    • Output Ripple < 10mVP-P
  • External Compensation: Fast Transient Response and Current Sharing (LT8643S-2)
  • Fast Minimum Switch On-Time: 30ns
  • Low Dropout Under All Conditions: 100mV at 1A
  • Forced Continuous Mode
  • Adjustable and Synchronizable: 200kHz to 3MHz
  • Output Soft-Start and Tracking
  • Small 24-Lead 4mm × 4mm LQFN Package

Product Details

The LT8640S-2/LT8643S-2 synchronous step-down regulator features Silent Switcher architecture designed to minimize EMI emissions while delivering high efficiency at high switching frequencies. Peak current mode control with a 30ns minimum on-time allows high step-down ratios even at high switching frequencies. The LT8643S-2 has external compensation to enable current sharing and fast transient response at high switching frequencies.

Burst Mode operation enables ultralow 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.

Applications

  • Automotive and Industrial Supplies
  • 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.

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:

LT8640
LT8640-1

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.

LTPowerCAD

Design tools for the following parts are available in LTpowerCAD:

LT8640

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.

PCN-PDN Information

Discussions

LT8640S-2 Discussions

RE: Fail safe feature of ADM3485EARZ
1 day(s) ago in Interface and Isolation
RE: ADL5317 Voltage Noise
2 day(s) ago in RF and Microwave
LT8640S-2 Didn't find what you were looking for? Ask the Analog community »

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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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