Data Sheet

LT83401/LT83402

analog.com

Rev. 0

2 of 44

TABLE OF CONTENTS

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

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

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

Revision History ....................................................................................................................................................................................3

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

Absolute Maximum Ratings ..................................................................................................................................................................8

Pin Configurations and Functional Descriptions .................................................................................................................................9

Typical Performance Characteristics .................................................................................................................................................12

Block Diagram .....................................................................................................................................................................................19

Theory of Operation............................................................................................................................................................................20

Applications Information....................................................................................................................................................................21

Low-Frequency Output Noise ........................................................................................................................................................21

Filtering Switching Ripple and High-Frequency Noise..................................................................................................................21

PCB Layout Recommendations .....................................................................................................................................................22

Forced Continuous Mode (FCM).....................................................................................................................................................24

Pulse-Skipping Mode......................................................................................................................................................................24

Synchronization..............................................................................................................................................................................24

Setting the Switching Frequency ...................................................................................................................................................25

Operating Frequency Selection and Trade-Offs ............................................................................................................................25

Inductor Selection and Maximum Output Current........................................................................................................................26

Overcurrent Protection (OCP) ........................................................................................................................................................28

Input Capacitors .............................................................................................................................................................................28

Output Capacitor and Output Ripple.............................................................................................................................................28

Output Voltage................................................................................................................................................................................29

Output Voltages Above 15V ............................................................................................................................................................31

High VOUT Considerations ................................................................................................................................................................31

Output Voltages Below 0.5V ...........................................................................................................................................................31

Output Sensing and Stability .........................................................................................................................................................31

Frequency Compensation ..............................................................................................................................................................32

EN/UVLO Pin ...................................................................................................................................................................................33

INTVCC Regulator .............................................................................................................................................................................33

SET Pin Capacitor: Noise and Soft-Start ........................................................................................................................................33

Fast Start-Up...................................................................................................................................................................................36

Programmable Power Good...........................................................................................................................................................36