AS3688

austriami crosyst ems

Datasheet, Confidential

www.austriamicrosystems.com (ptr,tje)

Revision 1.1.1 / 20060707

4 - 70

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

Analog LDO .............................................................................................................................................. 8

7.1.1

LDO Registers............................................................................................................................... 10

7.2

Step Up DC/DC Converter...................................................................................................................... 12

7.2.1

Feedback Selection....................................................................................................................... 13

7.2.2

Overvoltage Protection in Current Feedback Mode....................................................................... 14

7.2.3

Voltage Feedback ......................................................................................................................... 14

7.2.4

PCB Layout Tips ........................................................................................................................... 15

7.2.5

Step up Registers.......................................................................................................................... 16

7.3

Charge Pump.......................................................................................................................................... 17

7.3.1

Charge Pump Mode Switching ...................................................................................................... 19

7.3.2

Soft Start ....................................................................................................................................... 20

7.3.3

Charge Pump Registers ................................................................................................................ 20

7.3.4

Usage of PCB Wire Inductance..................................................................................................... 23

7.4

Current Sinks .......................................................................................................................................... 24

7.4.1

High Voltage Current Sinks CURR1, CURR2 ............................................................................... 24

7.4.2

High Current Sinks CURR30, CURR31, CURR32, CURR33 ........................................................ 26

7.4.3

RGB Current Sinks RGB1, RGB2, RGB3 (VANA2,cpext) ............................................................. 31

7.4.4

General Purpose Current Sinks CURR41, CURR42, CURR43..................................................... 34

7.4.5

LED Pattern Generator.................................................................................................................. 35

7.4.6

Overtemp comparator ................................................................................................................... 39

7.4.7

External chargepump .................................................................................................................... 40

7.4.8

PWM Generator ............................................................................................................................ 41

7.5

General Purpose Input / Outputs ............................................................................................................ 46

7.5.1

GPIO Characteristics..................................................................................................................... 47

7.5.2

GPIO Registers ............................................................................................................................. 48

7.6

LED Test................................................................................................................................................. 50

7.6.1

Function Testing for single LEDs connected to the Charge Pump ................................................ 50

7.6.2

Function Testing for LEDs connected to the Step Up DCDC Converter........................................ 51

7.7

Analog-To-Digital Converter ................................................................................................................... 52

ADC Registers............................................................................................................................... 53

7.7.1

53

7.8

Power-On Reset ..................................................................................................................................... 55

7.9

Temperature Supervision........................................................................................................................ 55

7.9.1

Temperature Supervision Registers .............................................................................................. 56

7.10

Serial Interface........................................................................................................................................ 56

7.10.1

Serial Interface Features ............................................................................................................... 56

7.10.2

Device Address Selection ............................................................................................................. 56

7.11

Operating Modes .................................................................................................................................... 59

8

Registermap................................................................................................................................................... 60

9

External Components..................................................................................................................................... 62

10

Pinout and Packaging ............................................................................................................................. 64

10.1

Pin Description........................................................................................................................................ 64

10.2

Package Drawings and Markings ........................................................................................................... 66

11

Ordering Information ............................................................................................................................... 68