ADP1823

Rev. A | Page 2 of 32

TABLE OF CONTENTS

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

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

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

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

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

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

Absolute Maximum Ratings............................................................ 5

ESD Caution.................................................................................. 5

Functional Block Diagram .............................................................. 6

Pin Configuration and Function Descriptions............................. 7

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

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

Input Power ................................................................................. 13

Start-Up Logic............................................................................. 13

Internal Linear Regulator .......................................................... 13

Oscillator and Synchronization ................................................ 13

Error Amplifier ........................................................................... 14

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

Power OK Indicator ................................................................... 14

Tracking ....................................................................................... 14

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

Current Limit .............................................................................. 15

Applications Information .............................................................. 16

Selecting the Input Capacitor ................................................... 16

Selecting the MOSFETS ............................................................ 17

Setting the Current Limit .......................................................... 18

Feedback Voltage Divider ......................................................... 18

Compensating the Voltage Mode Buck Regulator................. 18

Soft Start ...................................................................................... 22

Voltage Tracking......................................................................... 22

Coincident Tracking .................................................................. 22

Ratiometric Tracking ................................................................. 23

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

PCB Layout Guidelines.................................................................. 25

LFCSP Package Considerations................................................ 26

Application Circuits ....................................................................... 29

Outline Dimensions ....................................................................... 31

Ordering Guide .......................................................................... 31

REVISION HISTORY

11/06—Rev. 0 to Rev. A

Changes to Features and Applications Sections ........................... 1

Changes to Specifications Section .................................................. 3

Changes to Absolute Maximum Ratings Section ......................... 5

Replaced Theory of Operation Section ....................................... 13

Added Feedback Voltage Divider Section ................................... 18

Changes to Ratiometric Tracking Section................................... 23

Replaced PCB Layout Guidelines Section................................... 25

Added Application Circuits Section............................................. 29

Changes to Ordering Guide .......................................................... 31

4/06—Revision 0: Initial Version