Data Sheet

LT8349

analog.com

Rev B

3 of 29

TABLE OF CONTENTS

Features......................................................................................................................................................................................................1

Applications ...............................................................................................................................................................................................1

General Description...................................................................................................................................................................................1

Typical Application....................................................................................................................................................................................1

Revision History .........................................................................................................................................................................................2

Specifications.............................................................................................................................................................................................4

Absolute Maximum Ratings ......................................................................................................................................................................6

Pin Configurations and Function Descriptions........................................................................................................................................7

Typical Performance Characteristics .......................................................................................................................................................9

Block Diagram..........................................................................................................................................................................................12

Theory of Operation ................................................................................................................................................................................13

Multiphase Operation .........................................................................................................................................................................13

Applications Information ........................................................................................................................................................................15

Programming VIN Turn-On and Turn-Off Thresholds with the EN/UVLO Pin...................................................................................15

Light Load Current Operation ............................................................................................................................................................15

Switching Frequency and Synchronization.......................................................................................................................................17

Spread Spectrum Frequency Modulation .........................................................................................................................................19

FB Resistor Network and the Quiescent Current at No Load ...........................................................................................................19

Overvoltage Lockout...........................................................................................................................................................................20

Start-Up ...............................................................................................................................................................................................20

Inductor Selection...............................................................................................................................................................................21

Input Capacitor Selection...................................................................................................................................................................21

Output Capacitor Selection................................................................................................................................................................22

Frequency Compensation ..................................................................................................................................................................22

Board Layout .......................................................................................................................................................................................23

Thermal Considerations .....................................................................................................................................................................24

Typical Applications ...............................................................................................................................................................................26

PACKAGE DESCRIPTION ..........................................................................................................................................................................27

Related Parts............................................................................................................................................................................................28

Ordering Guide.........................................................................................................................................................................................28