Datasheet

ADP1850 Data Sheet
Rev. A | Page 2 of 32
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications ....................................................................................... 1
General Description ......................................................................... 1
Typical Operation Circuit ................................................................ 1
Revision History ............................................................................... 2
Specifications ..................................................................................... 3
Absolute Maximum Ratings ............................................................ 5
ESD Caution .................................................................................. 5
Simplified Block Diagram ............................................................... 6
Pin Configuration and Function Descriptions ............................. 7
Typical Performance Characteristics ............................................. 9
Theory of Operation ...................................................................... 12
Control Architecture .................................................................. 12
Oscillator Frequency .................................................................. 12
Modes of Operation ................................................................... 13
Synchronization .......................................................................... 13
Synchronous Rectifier and Dead Time ................................... 14
Input Undervoltage Lockout ..................................................... 14
Internal Linear Regulator .......................................................... 14
Overvoltage Protection .............................................................. 14
Power Good ................................................................................. 14
Short-Circuit and Current-Limit Protection .......................... 15
Shutdown Control ...................................................................... 15
Thermal Overload Protection ................................................... 15
Applications Information .............................................................. 16
Setting the Output Voltage ........................................................ 16
Soft Start ...................................................................................... 16
Setting the Current Limit .......................................................... 16
Accurate Current-Limit Sensing .............................................. 17
Setting the Slope Compensation .............................................. 17
Setting the Current Sense Gain ................................................ 17
Input Capacitor Selection .......................................................... 18
Input Filter ................................................................................... 18
Boost Capacitor Selection ......................................................... 18
Inductor Selection ...................................................................... 18
Output Capacitor Selection ....................................................... 19
MOSFET Selection ..................................................................... 19
Loop Compensation (Single Phase Operation) ..................... 21
Configuration and Loop Compensation (Dual-Phase
Operation) ................................................................................... 22

Switching Noise and Overshoot Reduction ............................ 22
Voltage Tracking ......................................................................... 23
Indepdendent Power Stage Input Voltage ............................... 24
PCB Layout Guidelines .................................................................. 25
MOSFETs, Input Bulk Capacitor, and Bypass Capacitor ...... 25
High Current and Current Sense Paths ................................... 25
Signal Paths ................................................................................. 25
PGND Plane ................................................................................ 25
Feedback and Current-Limit Sense Paths ............................... 25
Switch Node ................................................................................ 26
Gate Driver Paths ....................................................................... 26
Output Capacitors ...................................................................... 26
Typical Operating Circuits ............................................................ 27
Outline Dimensions ....................................................................... 31
Ordering Guide .......................................................................... 31
REVISION HISTORY
4/12—Rev. 0 to Rev. A
Changes to Setting the Current Sense Gain Section .................. 17
Updated Outline Dimensions ....................................................... 31
11/10—Revision 0: Initial Version