Datasheet
ADP1828
Rev. C | Page 2 of 36
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 Configurations and Function Descriptions ........................... 8
Typical Performance Characteristics ........................................... 10
Theory of Operation ...................................................................... 15
Input Power ................................................................................. 15
Internal Linear Regulator .......................................................... 15
Soft Start ...................................................................................... 15
Error Amplifier........................................................................... 16
Current-Limit Scheme............................................................... 16
MOSFET Drivers........................................................................ 16
Setting the Output Voltage........................................................ 17
Switching Frequency Control and Synchronization.............. 17
Compensation............................................................................. 18
Power-Good Indicator............................................................... 18
Thermal Shutdown..................................................................... 18
Shutdown Control...................................................................... 18
Tracking....................................................................................... 18
Application Information................................................................ 19
Selecting the Input Capacitor ................................................... 19
Output LC Filter ......................................................................... 19
Selecting the MOSFETs ............................................................. 20
Setting the Current Limit.......................................................... 21
Accurate Current-Limit Sensing .............................................. 21
Feedback Voltage Divider ......................................................... 21
Compensating the Voltage Mode Buck Regulator................. 21
Soft Start ...................................................................................... 25
Switching Noise and Overshoot Reduction............................ 25
Voltage Tracking......................................................................... 25
Coincident Tracking .................................................................. 26
Ratiometric Tracking ................................................................. 26
Thermal Considerations............................................................ 28
PCB Layout Guideline ................................................................... 29
Recommended Component Manufacturers........................... 30
Application Circuits ....................................................................... 31
Outline Dimensions ....................................................................... 33
Ordering Guide .......................................................................... 34
REVISION HISTORY
11/10—Rev. B to Rev. C
Added 20-Lead LFCSP_WQ .............................................Universal
Changes to Features and General Description Sections.............. 1
Changes to Table 2............................................................................ 6
Added Figure 4; Renumbered Sequentially .................................. 8
Changes to Table 3............................................................................ 8
Updated Outline Dimensions....................................................... 33
Added Figure 59; Renumbered Sequentially .............................. 33
Changes to Ordering Guide .......................................................... 34
6/09—Rev. A to Rev. B
Changes to Figure 40...................................................................... 24
4/09—Rev. 0 to Rev. A
Changes to Features Section and General Description Section..1
Changes to IN Input Voltage Parameter and EN Input
Impedance to 5 V Zener Parameter, Table 1..................................3
Changes to Table 2.............................................................................6
Changes to Table 3.............................................................................8
Changes to Theory of Operation Section and Input Power
Section.............................................................................................. 14
Changes to MOSFET Drivers Section ......................................... 15
Updated Outline Dimensions....................................................... 32
Changes to Ordering Guide.......................................................... 32
9/07—Revision 0: Initial Version