LT8640S/LT8640SA

RECOMMENDED FOR NEW DESIGNS

42V, 6A Synchronous Step-Down Silent Switcher 2 with 2.5μA Quiescent Current

Data Sheet (Rev. D) Product Selection Table
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Overview

  • 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 5VOUT
    • Up to 95% Efficiency at 2MHz, 12VIN to 5VOUT
  • Wide Input Voltage Range: 3.4V to 42V
  • Output Voltage Range: 0.97V to 10V(LT8640S/LT8643S); 0.97V to (VIN – 0.5V) (LT8640SA/LT8643SA)
  • 6A Maximum Continuous, 7A Peak Output
  • Ultralow Quiescent Current Burst Mode® Operation
    • 2.5µA IQ Regulating 12VIN to 3.3VOUT (LT8640S/LT8640SA)
    • Output Ripple < 10mVP-P
  • External Compensation: Fast Transient Response and Current Sharing (LT8643S)
  • Robust High VOUT Operation (LT8640SA/LT8643SA)
    • Safely Tolerates High Reverse Current
  • 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
  • AEC-Q100 Qualified for Automotive Applications
LT8640S/LT8640SA
42V, 6A Synchronous Step-Down Silent Switcher 2 with 2.5μA Quiescent Current
LT8640S/LT8643S Application Circuit LT8640S/LT8643S Performance Graph LT8640S/LT8643S Pin Configuration LT8640S/LT8643S Pin Configuration
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Documentation

Data Sheet 1

User Guide 2

Design Note 2

Technical Articles 4

Evaluation Design File 1

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Software Resources

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Hardware Ecosystem

Parts Product Life Cycle Description
Protection Switches & Controllers 2
LTC4380
RECOMMENDED FOR NEW DESIGNS Low Quiescent Current Surge Stopper
LTC4368
RECOMMENDED FOR NEW DESIGNS 100V UV/OV and Reverse Protection Controller with Bidirectional Circuit Breaker
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Tools & Simulations

LTspice

Models for the following parts are available in LTspice:

  • LT8640
  • LT8640-1
  • LT8640A
  • LT8640S-2
  • LT8640SA

LTpowerCAD 1

Design tools for the following parts are available in LTpowerCAD:

  • LT8640
  • LT8640S
  • LT8640SA
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.

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.

Evaluation Kits

eval board
schematic 1
schematic 2
schematic 3
EVAL-LT8640SA-AZ

LT8640SA: 42V, 6A Synchronous Step-Down Silent Switcher 2

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Product Details

The demonstration circuit EVAL-LT8640SA-AZ is a 42V, 6A micropower synchronous step-down second generation Silent Switcher® with spread spectrum frequency modulation featuring the LT8640SA. The demo board is designed for 5V output from a 5.8V to 42V input. The wide input range allows a variety of input sources, such as automotive batteries and industrial supplies. The LT8640SA is a compact, ultra-low emission, high efficiency, and high speed synchronous monolithic step-down switching regulator. The integrated bypass capacitors optimize all the fast current loops and make it easier to minimize EMI/EMC emissions by reducing layout sensitivity. Selectable spread spectrum mode can further improve EMI/EMC performance. Ultra-low quiescent current in Burst Mode® operation achieves high efficiency at very light loads. Fast minimum on-time of 30ns enables high VIN to low VOUT conversion at high frequency.

Please see user guide for the full description.

eval board
schematic 4
schematic 5
schematic 6
schematic 7
DC2530A

LT8640S Demo Board | Synchronous Buck Silent Switcher 2, 5.8V ≤ VIN ≤ 42V, VOUT = 5V @ 6A, fSW = 2MHz

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Product Details

Demonstration circuit 2530A is a 42V, 6A micropower synchronous step-down second generation Silent Switcher® with spread spectrum frequency modulation featuring the LT8640S. The demo board is designed for 5V output from a 5.8V to 42V input. The wide input range allows a variety of input sources, such as automotive batteries and industrial supplies. The LT8640S is a compact, ultralow emission, high efficiency, and high speed synchronous monolithic step-down switching regulator. The integrated bypass capacitors optimize all the fast current loops and make it easier to minimize EMI/EMC emissions by reducing layout sensitivity. Selectable spread spectrum mode can further improve EMI/EMC performance. Ultralow quiescent current in Burst Mode® operation achieves high efficiency at very light loads. Fast minimum on-time of 30ns enables high VIN to low VOUT conversion at high frequency.
EVAL-LT8640SA-AZ
LT8640SA: 42V, 6A Synchronous Step-Down Silent Switcher 2
EVAL-LT8640SA-AZ Board Photo Angle View EVAL-LT8640SA-AZ Board Photo Top View EVAL-LT8640SA-AZ Board Photo Bottom View
DC2530A
LT8640S Demo Board | Synchronous Buck Silent Switcher 2, 5.8V ≤ VIN ≤ 42V, VOUT = 5V @ 6A, fSW = 2MHz
DC2530A Evaluation Board DC2530A Evaluation Board - Top View DC2530A Evaluation Board - Bottom View DC2530A

Reference Designs

NOVPED iMX6 QP Dev Kit
NOVPED iMX6 QP Dev Kit
NOVPED iMX66 Power Tree
NXP NOVPED iMX6 QP Circuits from the lab

NXP iMX6 Platform EVK Hardware Verified Design for IO and Robust Power Supply

View Detailed Reference Design

Features and Benefits

  • Analog Devices has worked closely with FPGA and processor manufacturers to develop verified power solutions that optimize cost, size and efficiency in high performance applications
  • Our reference designs are supported by an intuitive design tool set and IP
  • Our team can provide designs for quick prototypes that can speed time to market in the most complex applications
NXP NOVPED iMX6 QP
NXP iMX6 Platform EVK Hardware Verified Design for IO and Robust Power Supply
NOVPED iMX6 QP Dev Kit
NOVPED iMX66 Power Tree

Latest Discussions

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LT8640s output negative voltage
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Clarification on LT8640S Output Voltage Specification
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Can i use LT8640 (LT8643) in below ways to achieve -10V output
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