LT8641

RECOMMENDED FOR NEW DESIGNS

65V, 3.5A Synchronous Step-Down Silent Switcher with 2.5μA Quiescent Current

Data Sheet (Rev. C) Product Selection Table

Part Models: 12
1ku List Price: Starting From $5.19

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Overview

Silent Switcher^® Architecture

Ultralow EMI Emissions
Spread Spectrum Frequency 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: 3V to 65V
3.5A Maximum Continuous Output, 5A Peak Transient Output
Fast Minimum Switch-On Time: 35ns

Ultralow Quiescent Current Burst Mode^® Operation

2.5μA I_Q Regulating 12V_IN to 3.3V_OUT
Output Ripple < 10mV_P-P

Low Dropout Under All Conditions: 130mV at 1A
Safely Tolerates Inductor Saturation in Overload
Adjustable and Synchronizable: 200kHz to 3MHz
Peak Current Mode Operation
Output Soft-Start and Tracking
Small 18-Lead 3mm × 4mm QFN
AEC-Q100 Qualified for Automotive Applications

The LT8641 step-down regulator features Silent Switcher architecture designed to minimize EMI/EMC emissions while delivering high efficiency at frequencies up to 3MHz. Assembled in a 3mm × 4mm QFN, the monolithic construction with integrated power switches and inclusion of all necessary circuitry yields a solution with a minimal PCB footprint. An ultralow 2.5μA quiescent current—with the output in full regulation—enables applications requiring highest efficiency at very small load currents. Transient response remains excellent and output voltage ripple is below 10mV_P-P at any load, from zero to full current.

The LT8641 allows high V_IN to low V_OUT conversion at high frequency with a fast minimum top switch on-time of 35ns. Operation is safe in overload even with a saturated inductor.

Essential features are included and easy to use: An open-drain PG pin signals when the output is in regulation. The SYNC/MODE pin selects between Burst Mode, pulse-skipping, or spread spectrum mode, and also allows synchronization to an external clock. Soft-start and tracking functionality is accessed via the TR/SS pin. An accurate enable threshold can be set using the EN/UV pin and a resistor at the RT pin programs switch frequency.

APPLICATIONS

Automotive and Industrial Supplies
General Purpose Step-Down
GSM Power Supplies

Part Models: 12
1ku List Price: Starting From $5.19

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
LT8641EUDC#PBF	20(18)-Lead QFN (3mm x 4mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT8641EUDC#TRPBF	20(18)-Lead QFN (3mm x 4mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT8641HUDC#PBF	20(18)-Lead QFN (3mm x 4mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT8641HUDC#TRPBF	20(18)-Lead QFN (3mm x 4mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT8641HUDC#WPBF	20(18)-Lead QFN (3mm x 4mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT8641HUDC#WTRPBF	20(18)-Lead QFN (3mm x 4mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT8641IUDC#PBF	20(18)-Lead QFN (3mm x 4mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT8641IUDC#TRPBF	20(18)-Lead QFN (3mm x 4mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT8641IUDC#WPBF	20(18)-Lead QFN (3mm x 4mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT8641IUDC#WTRPBF	20(18)-Lead QFN (3mm x 4mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT8641JUDC#WPBF	20(18)-Lead QFN (3mm x 4mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT8641JUDC#WTRPBF	20(18)-Lead QFN (3mm x 4mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys

Part Models	Product Lifecycle	PCN

Sep 30, 2020 - 20_0293 Test Site Transfer from Analog Devices Singapore to UTAC Thailand
		PCN20_0293_Form Material_Report Delta Qualification Matrix Qualification Results Summary Test Correlation Report Test Correlation Report Other Qualification Results Summary
LT8641EUDC#PBF	PRODUCTION
LT8641EUDC#TRPBF	PRODUCTION
LT8641HUDC#PBF	PRODUCTION
LT8641HUDC#TRPBF	PRODUCTION
LT8641IUDC#PBF	PRODUCTION
LT8641IUDC#TRPBF	PRODUCTION
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
LT8641EUDC#PBF	PRODUCTION
LT8641EUDC#TRPBF	PRODUCTION
LT8641HUDC#PBF	PRODUCTION
LT8641HUDC#TRPBF	PRODUCTION
LT8641IUDC#PBF	PRODUCTION
LT8641IUDC#TRPBF	PRODUCTION

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

Software Resources

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Hardware Ecosystem

Parts	Product Life Cycle	Description
Protection Switches & Controllers 1
LT4363	RECOMMENDED FOR NEW DESIGNS	High Voltage Surge Stopper with Current Limit

Parts	Product Life Cycle	Description
LT8641A	RECOMMENDED FOR NEW DESIGNS	65V, 3.5A/5A Peak Synchronous Step-Down Silent Switcher with 2.5μA Quiescent Current

Tools & Simulations

LTspice 1

LT8641 Demo Circuit - 2MHz µPower Ultralow EMI Buck Converter (5.5-65V to 5V @ 3.5A)

Models for the following parts are available in LTspice:

LT8641

LTpowerCAD 1

LT8641 Project - 65V, 3.5A Monolithic µPower Synchronous Buck Silent Switcher (5.5-65V to 5V @ 3.5A)

Design tools for the following parts are available in LTpowerCAD:

LT8641
LT8641A

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

LT8641 Demo Board | Synchronous Buck, Silent Switcher, 5.5V ≤ VIN ≤ 65V, VOUT = 5V @ 3.5A, fSW = 2MHz

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Product Details

Demonstration circuit 2373A is a 65V, 3.5A micropower synchronous step-down Silent Switcher^® with spread spectrum frequency modulation featuring the LT8641. The demo board is designed for 5V output from a 5.5V to 65V input. The wide input range allows a variety of input sources, such as automotive batteries and industrial supplies. The LT8641 is a compact, ultralow emission, high efficiency, high speed synchronous monolithic step-down switching regulator that consumes only 2.5μA of quiescent current when output is regulated at 5V. Top and bottom power switches, compensation components and other necessary circuits are inside of the LT8641 to minimize external components and simplify design.

Resources

DC2373A - Schematic
3/15/2016

DC2373A - Demo Manual
3/15/2016

DC2373A - Design Files
4/21/2016

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LT8641

Overview

Documentation

Data Sheet 1

Reliability Data 1

User Guide 1

Technical Articles 2

Video 1

Book & eBook 1

Solutions Bulletin & Brochure 1

Rarely Asked Question Page 1

Webcast 1