LT8645S
Info : RECOMMENDED FOR NEW DESIGNS
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LT8645S

65V, 8A 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 6
1ku List Price Starting From $5.83
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 95% Efficiency at 1MHz, 12VIN to 5VOUT
    • Up to 94% Efficiency at 2MHz, 12VIN to 5VOUT
  • Wide Input Voltage Range: 3.4V to 65V
  • Ultralow Quiescent Current Burst Mode Operation
    • 2.5μA IQ Regulating 12VIN to 3.3VOUT (LT8645S) 
    • Output Ripple < 10mVP-P
  • External Compensation: Fast Transient Response and Current Sharing (LT8646S)
  • Fast Minimum Switch On-Time: 40ns
  • Low Dropout Under All Conditions: 60mV at 1A
  • Adjustable and Synchronizable: 200kHz to 2.2MHz
  • Peak Current Mode Operation 
  • Output Soft-Start and Tracking
  • Small 32-Lead 6mm × 4mm LQFN Package
  • AEC-Q100 Qualified for Automotive Applications
Additional Details
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The LT8645S/LT8646S 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.

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 40ns minimum on-time allows high step-down ratios even at high switching frequencies. The LT8646S has external compensation to enable current sharing and fast transient response at high switching frequencies.

Burst Mode® operation enables ultralow standby current consumption, pulse-skipping mode allows full switching frequency at lower output loads, or spread spectrum operation can further reduce EMI emissions.

Applications

  • Automotive and Industrial Supplies
  • General Purpose Step-Down
  • GSM Power Supplies
Part Models 6
1ku List Price Starting From $5.83

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Documentation

Documentation

Part Model Pin/Package Drawing Documentation CAD Symbols, Footprints, and 3D Models
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LT8645SIV#PBF
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LT8645SIV#TRPBF
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Product Lifecycle

PCN

Feb 6, 2024

- 24_0002

Qualification of New Mold Compound, SMT Paste and Pillar Diameter Change for LT8645S, LT8645S-2, LT8646S

LT8645SEV#PBF

PRODUCTION

LT8645SEV#WPBF

PRODUCTION

LT8645SIV#PBF

PRODUCTION

LT8645SIV#TRPBF

PRODUCTION

LT8645SIV#WPBF

PRODUCTION

LT8645SIV#WTRPBF

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

Feb 6, 2024

- 24_0002

arrow down

Qualification of New Mold Compound, SMT Paste and Pillar Diameter Change for LT8645S, LT8645S-2, LT8646S

LT8645SEV#PBF

PRODUCTION

LT8645SEV#WPBF

PRODUCTION

LT8645SIV#PBF

PRODUCTION

LT8645SIV#TRPBF

PRODUCTION

LT8645SIV#WPBF

PRODUCTION

LT8645SIV#WTRPBF

PRODUCTION

Apr 11, 2019

- 19_0067

arrow down

Notification of Wafer Fab Location Change for 0.35 BCD Process

Software & Part Ecosystem

Software & Part Ecosystem

Evaluation Kit

Evaluation Kits 1

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DC2468A

LT8645S Demo Board | Sync Buck Silent Switcher, 5.6V ≤ VIN ≤ 65V, VOUT = 5V @ 8A, fSW=2MHz

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DC2468A

LT8645S Demo Board | Sync Buck Silent Switcher, 5.6V ≤ VIN ≤ 65V, VOUT = 5V @ 8A, fSW=2MHz

LT8645S Demo Board | Sync Buck Silent Switcher, 5.6V ≤ VIN ≤ 65V, VOUT = 5V @ 8A, fSW=2MHz

Product Detail

Demonstration circuit 2468A is a 65V, 8A micropower synchronous step-down second generation Silent Switcher® with spread spectrum frequency modulation featuring the LT8645S. The demo board is designed for 5V output from a 5.6V to 65V input. The wide input range allows a variety of input sources, such as automotive batteries and industrial supplies. The LT8645S 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 40ns enables high VIN to low VOUT conversion at high frequency.


 


 


Tools & Simulations

Tools & Simulations 2

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.

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