LT8643S
Info : RECOMMENDED FOR NEW DESIGNS
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LT8643S

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

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Info : RECOMMENDED FOR NEW DESIGNS tooltip
Info : RECOMMENDED FOR NEW DESIGNS tooltip
Part Details
Part Models 8
1ku List Price Starting From $5.48
Features
  • 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
  • 6A Maximum Continuous, 7A Peak Output
  • Ultralow Quiescent Current Burst Mode® Operation
    • 2.5μA IQ Regulating 12VIN to 3.3VOUT (LT8640S)
    • Output Ripple < 10mVP-P
  • External Compensation: Fast Transient Response and Current Sharing (LT8643S)
  • 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
Additional Details
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The LT8640S/LT8643S 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 reducing layout sensitivity. This performance makes the LT8640S/LT8643S ideal for noise-sensitive applications and environments.

Peak current mode control with a 30ns minimum on-time allows high step-down ratios even at high switching frequencies. The LT8643S 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
Part Models 8
1ku List Price Starting From $5.48

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Documentation

Documentation

Part Model Pin/Package Drawing Documentation CAD Symbols, Footprints, and 3D Models
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Product Lifecycle

PCN

Sep 15, 2023

- 23_0182

Notification of Qualification of Pillar Size Update for LT3977, LT3978, LT8636, LT8637, LT8640S, LT8640S-2, LT8643S, LT8643S-2

LT8643SEV#PBF

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PRODUCTION

Apr 11, 2019

- 19_0067

Notification of Wafer Fab Location Change for 0.35 BCD Process

Filter by Model

reset

Reset Filters

Part Models

Product Lifecycle

PCN

Sep 15, 2023

- 23_0182

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Notification of Qualification of Pillar Size Update for LT3977, LT3978, LT8636, LT8637, LT8640S, LT8640S-2, LT8643S, LT8643S-2

LT8643SEV#PBF

PRODUCTION

LT8643SEV#TRPBF

PRODUCTION

LT8643SEV#WPBF

PRODUCTION

LT8643SEV#WTRPBF

PRODUCTION

LT8643SIV#PBF

PRODUCTION

LT8643SIV#TRPBF

PRODUCTION

LT8643SIV#WPBF

PRODUCTION

LT8643SIV#WTRPBF

PRODUCTION

Apr 11, 2019

- 19_0067

arrow down

Notification of Wafer Fab Location Change for 0.35 BCD Process

Software and Part Ecosystem

Software and Part Ecosystem

Evaluation Kit

Evaluation Kits 1

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DC2658A

LT8643S Demo Board | VIN = 5.8V to 42V with VOUT = 5V at 6A @ 2MHz

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DC2658A

LT8643S Demo Board | VIN = 5.8V to 42V with VOUT = 5V at 6A @ 2MHz

LT8643S Demo Board | VIN = 5.8V to 42V with VOUT = 5V at 6A @ 2MHz

Product Detail

Demonstration circuit 2658A is a 42V, 6A synchronous step-down second generation SILENT SWITCHER with spread spectrum frequency modulation featuring the LT8643S. 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 LT8643S 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. Fast minimum on-time of 30ns enables high VIN to low VOUT conversion at high frequency.

Tools & Simulations

Tools & Simulations 1

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