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

Part Models: 10
1ku List Price: Starting From $5.48

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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 96% Efficiency at 1MHz, 12V_IN to 5V_OUT
- Up to 95% Efficiency at 2MHz, 12V_IN to 5V_OUT
Wide Input Voltage Range: 3.4V to 42V
Output Voltage Range: 0.97V to 10V(LT8640S/LT8643S); 0.97V to (V_IN – 0.5V) (LT8640SA/LT8643SA)
6A Maximum Continuous, 7A Peak Output
Ultralow Quiescent Current Burst Mode^® Operation
- 2.5µA IQ Regulating 12V_IN to 3.3V_OUT (LT8640S/LT8640SA)
- Output Ripple < 10mV_P-P

External Compensation: Fast Transient Response and Current Sharing (LT8643S)
Robust High V_OUT 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

Part Models: 10
1ku List Price: Starting From $5.48

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
LT8640SAAV#PBF	24-Lead LQFN (4mm x 4mm x 0.94mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT8640SAAV#TRPBF	24-Lead LQFN (4mm x 4mm x 0.94mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT8640SEV#PBF	24-Lead LQFN (4mm x 4mm x 0.94mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT8640SEV#TRPBF	24-Lead LQFN (4mm x 4mm x 0.94mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT8640SEV#WPBF	24-Lead LQFN (4mm x 4mm x 0.94mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT8640SEV#WTRPBF	24-Lead LQFN (4mm x 4mm x 0.94mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT8640SIV#PBF	24-Lead LQFN (4mm x 4mm x 0.94mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT8640SIV#TRPBF	24-Lead LQFN (4mm x 4mm x 0.94mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT8640SIV#WPBF	24-Lead LQFN (4mm x 4mm x 0.94mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT8640SIV#WTRPBF	24-Lead LQFN (4mm x 4mm x 0.94mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys

Part Models	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
		PCN23_0182_Form Material_Report Qualification Results Summary Delta Qualification Matrix
LT8640SEV#PBF	PRODUCTION
LT8640SEV#TRPBF	PRODUCTION
LT8640SEV#WPBF
LT8640SEV#WTRPBF
LT8640SIV#PBF	PRODUCTION
LT8640SIV#TRPBF	PRODUCTION
LT8640SIV#WPBF	PRODUCTION
LT8640SIV#WTRPBF
May 17, 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
LT8640SEV#PBF	PRODUCTION
LT8640SIV#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
LT8645S	RECOMMENDED FOR NEW DESIGNS	65V, 8A Synchronous Step-Down Silent Switcher 2 with 2.5μA Quiescent Current

Tools & Simulations

LTspice 1

LT8640S - Step-Down (Buck) Regulators

Models for the following parts are available in LTspice:

LT8640
LT8640-1
LT8640A
LT8640S-2

LTpowerCAD 1

LT8640S Project - DC2530A 5.8V-42VIN to 5V/6A

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

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 V_IN to low V_OUT conversion at high frequency.

Resources

DC2530A - Schematic
33.00K

DC2530A - Design Files
1.00M

DC2530A - Demo Manual
562.00K

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 V_OUT conversion at high frequency.

Please see user guide for the full description.

Resources

EVAL-LT8640SA-AZ User Guide: LT8640SA | 42V, 6A Synchronous Step-Down Silent Switcher 2 (Rev.0)
756.68 K

EVAL-LT8640SA-AZ Design File
3.37 M

Reference Designs

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

Part Used

Latest Discussions

1 Years Ago

LT8640S/
LT8640SA

Part Details

Documentation

Data Sheet 1

Reliability Data 1

User Guide 2

Design Note 2

Technical Articles 4

Evaluation Design File 1

Solutions Bulletin & Brochure 1

Book & eBook 2

Rarely Asked Question Page 1

Webcast 2

Hardware Ecosystem

Tools & Simulations

LTspice 1

Models for the following parts are available in LTspice:

LTpowerCAD 1

Evaluation Kits

Product Details

Resources

Product Details

Resources

Reference Designs

Features and Benefits

Part Used

Latest Discussions

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