ADP1828

Rev. 0 | Page 2 of 32

TABLE OF CONTENTS

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

 

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

 

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

 

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

 

Specifications..................................................................................... 3

 

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

 

ESD Caution.................................................................................. 6

 

Simplified Block Diagram ............................................................... 7

 

Pin Configuration and Function Descriptions............................. 8

 

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

 

Theory of Operation ...................................................................... 14

 

Input Power ................................................................................. 14

 

Internal Linear Regulator .......................................................... 14

 

Soft Start ...................................................................................... 14

 

Error Amplifier ........................................................................... 15

 

Current-Limit Scheme............................................................... 15

 

MOSFET Drivers........................................................................ 15

 

Setting the Output Voltage ........................................................ 16

 

Switching Frequency Control and Synchronization.............. 16

 

Compensation............................................................................. 17

 

Power-Good Indicator ............................................................... 17

 

Thermal Shutdown..................................................................... 17

 

Shutdown Control...................................................................... 17

 

Tracking ....................................................................................... 17

 

Application Information................................................................ 18

 

Selecting the Input Capacitor ................................................... 18

 

Output LC Filter ......................................................................... 18

 

Selecting the MOSFETs ............................................................. 19

 

Setting the Current Limit .......................................................... 20

 

Accurate Current-Limit Sensing .............................................. 20

 

Feedback Voltage Divider ......................................................... 20

 

Compensating the Voltage Mode Buck Regulator................. 20

 

Soft Start ...................................................................................... 24

 

Switching Noise and Overshoot Reduction............................ 24

 

Voltage Tracking......................................................................... 24

 

Coincident Tracking .................................................................. 25

 

Ratiometric Tracking ................................................................. 25

 

Thermal Considerations............................................................ 27

 

PCB Layout Guideline ................................................................... 28

 

Recommended Component Manufacturers........................... 29

 

Application Circuits ....................................................................... 30

 

Outline Dimensions ....................................................................... 32

 

Ordering Guide .......................................................................... 32

 

REVISION HISTORY

9/07—Revision 0: Initial Version