Datasheet

ADP1851 Data Sheet
Rev. 0 | Page 2 of 24
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications ....................................................................................... 1
General Description ......................................................................... 1
Typical Operation Circuit ................................................................ 1
Revision History ............................................................................... 2
Simplified Block Diagram ............................................................... 3
Specifications ..................................................................................... 4
Absolute Maximum Ratings ............................................................ 6
ESD Caution .................................................................................. 6
Pin Configuration and Function Descriptions ............................. 7
Typical Performance Characteristics ............................................. 9
Theory of Operation ...................................................................... 11
Control Architecture .................................................................. 11
Oscillator Frequency .................................................................. 11
Synchronization .......................................................................... 12
PWM and Pulse Skip Modes of Operation ............................. 12
Synchronous Rectifier and Dead Time ................................... 13
Input Undervoltage Lockout ..................................................... 13
Internal Linear Regulator .......................................................... 13
Overvoltage Protection .............................................................. 13
Power Good ................................................................................. 13
Short-Circuit and Current-Limit Protection .......................... 14
Enable/Disable Control ............................................................. 14
Thermal Overload Protection .................................................. 14
Applications Information .............................................................. 15
ADIsimPower Design Tool ....................................................... 15
Setting the Output Voltage ........................................................ 15
Soft Start ...................................................................................... 15
Setting the Current Limit .......................................................... 15
Accurate Current-Limit Sensing .............................................. 15
Input Capacitor Selection .......................................................... 15
VIN Pin Filter ............................................................................. 16
Boost Capacitor Selection ......................................................... 16
Inductor Selection ...................................................................... 16
Output Capacitor Selection....................................................... 16
MOSFET Selection ..................................................................... 17
Loop Compensation—Voltage Mode ...................................... 18
Loop Compensation—Current Mode ..................................... 19
Switching Noise and Overshoot Reduction ............................ 20
Voltage Tracking ......................................................................... 21
PCB Layout Guidelines.............................................................. 21
Typical Operating Circuits ............................................................ 22
Outline Dimensions ....................................................................... 23
Ordering Guide .......................................................................... 23
REVISION HISTORY
8/12—Revision 0: Initial Version