Copyright © Azoteq (Pty) Ltd 2011

IQS128 & IQS128LP Datasheet v2.4

Page 2 of 33

All Rights Reserved

November 2012

Contents

1

OVERVIEW ......................................................................................................................................................... 4

1.1

DEVICE VARIATIONS ................................................................................................................................................ 4

1.2

DEVICE................................................................................................................................................................. 4

1.3

OPERATION........................................................................................................................................................... 4

1.4

APPLICABILITY........................................................................................................................................................ 4

2

PIN-OUT ............................................................................................................................................................. 5

2.1

IQS128 ............................................................................................................................................................... 5

2.1.1

Pin-out........................................................................................................................................................... 5

2.1.2

Schematic...................................................................................................................................................... 5

2.1.3

Typical values ................................................................................................................................................ 5

2.2

IQS128L ............................................................................................................................................................. 6

2.2.1

Pin-out........................................................................................................................................................... 6

2.2.2

Schematic...................................................................................................................................................... 6

2.2.1

Typical values ................................................................................................................................................ 6

3

USER CONFIGURABLE OPTIONS.......................................................................................................................... 7

3.1

CONFIGURING DEVICES ........................................................................................................................................... 7

3.1.1

IQS128 User Selectable Options.................................................................................................................... 7

3.1.2

IQS128L User Selectable Options .................................................................................................................. 9

4

MEASURING CAPACITANCE USING THE CHARGE TRANSFER METHOD...............................................................11

5

DYCAL™.............................................................................................................................................................12

5.1

OPERATING PRINCIPLE .......................................................................................................................................... 13

5.2

NON-TOUCH MODE ............................................................................................................................................. 13

5.3

TOUCH MODE ..................................................................................................................................................... 13

6

CONFIGURABLE SETTINGS .................................................................................................................................14

6.1

EXT_CTRL: EXTERNAL CONTROL............................................................................................................................ 14

6.1.1

Charge Halt ................................................................................................................................................. 14

6.1.2

Halt LTA filter .............................................................................................................................................. 14

6.1.3

Pulse on CTRL: ............................................................................................................................................. 14

6.2

LOGIC............................................................................................................................................................... 15

6.3

RF NOISE ON IQS128/IQS128L............................................................................................................................ 15

6.3.1

ND: RF Noise Detection (IQS128) ................................................................................................................ 15

6.3.2

IQS128/IQS128L RF Noise Immunity ........................................................................................................... 15

6.4

PTHR[1:0] PROXIMITY THRESHOLD............................................................................................................................. 15

6.5

TTHR[2:0]TOUCH THRESHOLD ................................................................................................................................... 16

6.6

CTRL_DIRECTION ............................................................................................................................................. 16

6.7

THALT[1:0] FILTER HALT........................................................................................................................................... 17

6.8

LP[1:0] LOW POWER MODES (IQS128L) .................................................................................................................. 17

7

STREAMING MODE............................................................................................................................................18

8

AUTOMATIC TUNING IMPLEMENTATION (ATI)..................................................................................................19

8.1

ATI ................................................................................................................................................................... 19

8.1.1

ATI Target.................................................................................................................................................... 19

8.1.2

ATIBASE: Significance of ATI Base.................................................................................................................. 19

8.2

SENSITIVITY DUE TO ATI ........................................................................................................................................ 20

8.3

ATI PROCEDURE .................................................................................................................................................. 20

9

DYCAL SPECIFIC SETTINGS .................................................................................................................................21

9.1

REL_TTHR: RELEASE THRESHOLD (IQS128L)............................................................................................................ 21

9.2

DYCAL_OUTPUT (IQS128L) ............................................................................................................................. 21