LT8645S

RECOMMENDED FOR NEW DESIGNS

65V, 8A Synchronous Step-Down Silent Switcher 2 with 2.5μA Quiescent Current

Data Sheet (Rev. E) Product Selection Table

Part Models: 6
1ku List Price: Starting From $5.83

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Part Details

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, 12V_IN to 5V_OUT
- Up to 94% Efficiency at 2MHz, 12V_IN to 5V_OUT
Wide Input Voltage Range: 3.4V to 65V
Ultralow Quiescent Current Burst Mode Operation
- 2.5μA I_Q Regulating 12V_IN to 3.3V_OUT (LT8645S)
- Output Ripple < 10mV_P-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

Part Models: 6
1ku List Price: Starting From $5.83

Documentation

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. View our quality and reliability program and certifications for more information.

Part Model	Pin/Package Drawing	Documentation	CAD Symbols, Footprints, and 3D Models
LT8645SEV#PBF	32-Lead LQFN (6mm x 4mm x 0.94mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT8645SEV#WPBF	32-Lead LQFN (6mm x 4mm x 0.94mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT8645SIV#PBF	32-Lead LQFN (6mm x 4mm x 0.94mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT8645SIV#TRPBF	32-Lead LQFN (6mm x 4mm x 0.94mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT8645SIV#WPBF	32-Lead LQFN (6mm x 4mm x 0.94mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT8645SIV#WTRPBF	32-Lead LQFN (6mm x 4mm x 0.94mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys

Part Models	Product Lifecycle	PCN

Feb 6, 2024 - 24_0002 Qualification of New Mold Compound, SMT Paste and Pillar Diameter Change for LT8645S, LT8645S-2, LT8646S
		PCN24_0002_Form Material_Report Qualification Results Summary Delta Qualification Matrix Other
LT8645SEV#PBF	PRODUCTION
LT8645SEV#WPBF
LT8645SIV#PBF	PRODUCTION
LT8645SIV#TRPBF	PRODUCTION
LT8645SIV#WPBF	PRODUCTION
LT8645SIV#WTRPBF
Apr 11, 2019 - 19_0067 Notification of Wafer Fab Location Change for 0.35 BCD Process
		PCN19_0067_Form Material_Report Delta Qualification Matrix Qualification Results Summary Detailed Parts List Other
LT8645SEV#PBF	PRODUCTION
LT8645SIV#PBF	PRODUCTION

This is the most up-to-date revision of the Data Sheet.

Hardware Ecosystem

Parts	Product Life Cycle	Description
High Voltage Hot Swap Controllers 1
LTC4380	RECOMMENDED FOR NEW DESIGNS	Low Quiescent Current Surge Stopper
Surge Stopper, Overvoltage, and Overcurrent Protection 1
LTC4368	RECOMMENDED FOR NEW DESIGNS	100V UV/OV and Reverse Protection Controller with Bidirectional Circuit Breaker

Parts	Product Life Cycle	Description
LT8640S/ LT8640SA		42V, 6A Synchronous Step-Down Silent Switcher 2 with 2.5μA Quiescent Current

Tools & Simulations

LTspice 1

LT8645S - Step-Down (Buck) Regulators

LTpowerCAD 1

LT8645S Project - DC2468A 6-65Vin to 5Vout/8A, 2MHz

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^® 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

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

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Product Details

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 V_IN to low V_OUT conversion at high frequency.

Resources

DC2468A - Design Files
1.00M

DC2468A - Demo Manual
648.00K

DC2468A - Schematic
30.00K

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LT8645S

Part Details

Documentation

Data Sheet 1

Reliability Data 1

User Guide 1

Design Note 1

Technical Articles 3

Solutions Bulletin & Brochure 1

Book & eBook 1

Analog Dialogue 1

Webcast 2