Datasheet

ADM8845
Rev. C | Page 2 of 20
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications ....................................................................................... 1
General Description ......................................................................... 1
Functional Block Diagram .............................................................. 1
Revision History ............................................................................... 2
Specifications ..................................................................................... 3
Absolute Maximum Ratings ............................................................ 4
Thermal Characteristics .............................................................. 4
ESD Caution .................................................................................. 4
Pin Configuration and Function Descriptions ............................. 5
Typical Performance Characteristics ............................................. 6
Theory of Operation ...................................................................... 10
Output Current Capability ........................................................ 11
Automatic Gain Control ............................................................ 11
Current Matching ....................................................................... 11
Brightness Control with a Digital PWM Signal ..................... 11
LED Brightness Control Using a PWM Signal Applied to
V
PWM
............................................................................................. 13
LED Brightness Control Using a DC Voltage Applied to
V
BRIGHT
.......................................................................................... 13
Applications ..................................................................................... 14
Layout Considerations and Noise ............................................ 14
White LED Shorting .................................................................. 14
Driving Fewer than Six LEDs ................................................... 14
Driving Flash LEDs .................................................................... 15
Driving Camera Light, Main, and Sub LEDs.......................... 15
Driving Four Backlight White LEDs and Flash LEDs ........... 16
Power Efficiency ......................................................................... 17
Outline Dimensions ....................................................................... 18
Ordering Guide .......................................................................... 18
REVISION HISTORY
1/11—Rev. B to Rev. C
Changes to Figure 18 and Figure 19 ................................................ 8
Changes to Ordering Guide ........................................................... 18
4/10—Rev. A to Rev. B
Changes to Figure 2 ........................................................................... 5
Changes to Figure 4 ........................................................................... 6
Changes to Figure 16 to Figure 19 ................................................... 8
Changes to Brightness Control with a digital PWM
Signal Section ................................................................................... 11
Added Exposed Pad Notation to Outline Dimensions .............. 18
Changes to Ordering Guide ........................................................... 18
7/05—Re
v. 0 to Rev. A
Changes to Table 3 ............................................................................. 5
Changes to Table 7 ........................................................................... 12
Updated Outline Dimensions ........................................................ 18
Changes to Ordering Guide ........................................................... 18
10/04—Revision 0: Initial Version