AS3687/87XM

Datasheet

www.austriamicrosystems.com/AS3687

1v3-4

4 - 54

Table of Contents

1

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

2

Key Features.................................................................................................................................................. 1

3

Application ..................................................................................................................................................... 1

4

Block Diagram................................................................................................................................................ 2

5

Characteristics ............................................................................................................................................... 5

5.1

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

5.2

Operating Conditions .............................................................................................................................. 5

6

Typical Operating Characteristics .................................................................................................................. 6

7

Detailed Functional Description ..................................................................................................................... 8

7.1

Step Up DC/DC Converter...................................................................................................................... 8

7.1.1

Feedback Selection ......................................................................................................................... 9

7.1.2

Overvoltage Protection in Current Feedback Mode ......................................................................... 9

7.1.3

Voltage Feedback.......................................................................................................................... 10

7.1.4

PCB Layout Hints .......................................................................................................................... 11

7.1.5

Step up Registers .......................................................................................................................... 11

7.2

Charge Pump........................................................................................................................................ 13

7.2.1

Charge Pump Mode Switching ......................................................................................................15

7.2.2

Soft Start........................................................................................................................................ 16

7.2.3

Charge Pump Registers ................................................................................................................ 16

7.3

Current Sinks ........................................................................................................................................ 18

7.3.1

High Voltage Current Sinks CURR1, CURR2, CURR6.................................................................. 19

7.3.2

Current Sinks CURR30, CURR31, CURR32, CURR33................................................................. 21

7.3.3

LED Pattern Generator .................................................................................................................. 24

7.3.4

PWM Generator............................................................................................................................. 28

7.4

LED Test............................................................................................................................................... 33

7.4.1

Function Testing for single LEDs connected to the Charge Pump ................................................ 33

7.4.2

Function Testing for LEDs connected to the Step Up DCDC Converter ........................................ 34

7.5

Analog-To-Digital Converter ................................................................................................................. 34

7.5.1

ADC Registers ............................................................................................................................... 35

7.6

Audio controlled RGB LEDs (only AS3687XM)..................................................................................... 37

7.6.1

AGC............................................................................................................................................... 39

7.6.2

Audio Control Registers................................................................................................................. 41

7.7

Power-On Reset ................................................................................................................................... 42

7.7.1

Reset control register..................................................................................................................... 43

7.8

Temperature Supervision...................................................................................................................... 43

7.8.1

Temperature Supervision Registers .............................................................................................. 44

7.9

Serial Interface...................................................................................................................................... 44

7.9.1

Serial Interface Features ............................................................................................................... 44

7.9.2

Device Address Selection.............................................................................................................. 45

7.10 Operating Modes .................................................................................................................................. 47

8

Register Map................................................................................................................................................ 48

9

External Components .................................................................................................................................. 50

10 Pinout and Packaging .................................................................................................................................. 51

10.1 Pin Description...................................................................................................................................... 51

10.2 Package Drawings and Markings ......................................................................................................... 52

11 Ordering Information .................................................................................................................................... 53