IQS231-00000000-TSR - Azoteq - Datasheet.Directory

ProxSense® Series

IQS231 Datasheet v1.5

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IQS231 Datasheet

Single Channel Capacitive Proximity/Touch Controller for SAR applications

Features

 Pin compatible with

IQS127/128/227/228/211

 Replacement solution for the IQS128 to

meet SAR regulations (failsafe & long-term

activation testing) and improve performance

 Improved IQS128 DYCALTM operation with

quick release detection for improved SAR

safety

 Human detection options for start-up

detection and improved user experience

(non-default, FCC approval pending)

 1.75V to 3.6V Input voltage, trimmed to use

proximity detection with 1.8V digital

interface

 External threshold adjustment pin

(minimize need for pre-empted OTP

adjustments)

 Minimal external components (direct input

strap)

 Standalone failsafe mode (backwards

compatible failsafe output, short pulses on

output to indicate operational device)

 Default OTP options focus on safety and

passing SAR lab qualification, OTP

changes offer performance advantages

 Quick release detection – effectively

prevent false triggers

 Quick release

sensitivity options

 Projected capacitive

sensing option (self-

capacitance by default)

 I2C interface option (improved

compatibility)

 Extended controls in I2C mode (setup in

I2C, runtime with standalone output)

 Hand-held power on detection (safety

back-off feature using user interaction)

 Optional input for synchronized

implementations (input to instruct IC when

to sense)

 Synchronization output – failsafe pulses

may be used by the master to synchronize

on. Sensing is done after each pulse

 Synchronization input – Sensing is only

done while Sync input is low

 Low power sensing: 30Hz (default), 100Hz

 Constant sampling rates during all

power modes with rapidly debounced

output changes

Applications

 SAR Sensor

 Integrated hybrid designs (RF and

capacitive sensing combined)

 Movement sensing applications (user

interaction detection, anti-theft)

 Hold detection for screen activation

 On-ear detection

6 pin TSOT23-6

Representations only,

not actual markings

RoHS2

Compliant

TSOT23-6

-40°C to 85°C

IQS231

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IQS231 Datasheet v1.5

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Table of Contents

1 SUMMARY: PACKAGING AND PIN-OUT .............................................................................................................. 4

2 SUMMARY: ONE-TIME-PROGRAMMABLE (OTP) OPTIONS ................................................................................. 5

3 SUMMARY: PROGRAMMING REFERENCE (I2C MEMORY MAP) ........................................................................... 6

4 SUMMARY: FEATURES ........................................................................................................................................ 7

PIN COMPATIBILITY .............................................................................................................................................................. 7

DYCAL / QUICK RELEASE ...................................................................................................................................................... 7

USER INTERFACE SELECTION ................................................................................................................................................... 7

MOVEMENT DETECTION ....................................................................................................................................................... 8

SENSITIVITY ADJUSTMENT...................................................................................................................................................... 8

FAILSAFE HEARTBEAT ............................................................................................................................................................ 8

HIGH CONFIGURABILITY ........................................................................................................................................................ 8

SWITCH I2C TO STANDALONE ................................................................................................................................................. 8

SELF / PROJECTED SENSING ................................................................................................................................................... 9

HAND-HELD DETECTION DURING POWER-ON ............................................................................................................................. 9

SYNC INPUT ........................................................................................................................................................................ 9

AUTOMATIC TUNING (ATI).................................................................................................................................................... 9

REFERENCE SIGNAL BEHAVIOUR .............................................................................................................................................. 9

IMPROVED I2C INTERFACE ..................................................................................................................................................... 9

5 FEATURES: EXTENDED DETAILS .........................................................................................................................10

5.1 ATI (AUTOMATIC TUNING IMPLEMENTATION) ........................................................................................................... 10

5.2 SENSITIVITY ADJUSTMENT ...................................................................................................................................... 10

6 RECOMMENDED SAR CONFIGURATIONS ...........................................................................................................11

6.1 IQS128 REPLACEMENT CONFIGURATION .................................................................................................................. 11

6.2 FULL FEATURE CONFIGURATION ............................................................................................................................... 12

6.3 SHARED ELECTRODE WITH RF ANTENNA .................................................................................................................... 12

6.4 I2C SETUP WITH STANDALONE OUTPUT IN RUNTIME ..................................................................................................... 13

7 I2C PROGRAMMING GUIDE (SUMMARY) ...........................................................................................................14

7.1 ADD I2C CONNECTION .......................................................................................................................................... 14

7.2 I2C COMMAND STRUCTURE .................................................................................................................................... 15

7.3 CONTROL BYTE .................................................................................................................................................... 15

7.4 TEST MODE (ADDRESS 0X45) .................................................................................................................................. 15

7.5 I2C TYPICAL SETUP ............................................................................................................................................... 16

7.6 I2C READ (EVENT REGISTER) ................................................................................................................................... 16

8 CONFIGURATION OPTIONS................................................................................................................................17

8.1 OTP DETAILS: BANK 0 .......................................................................................................................................... 18

MOVEMENT TIME-OUT ....................................................................................................................................................... 18

MOVEMENT THRESHOLD ..................................................................................................................................................... 18

QUICK RELEASE THRESHOLD ................................................................................................................................................. 18

QUICK RELEASE BETA .......................................................................................................................................................... 18

8.2 OTP DETAILS: BANK 1 .......................................................................................................................................... 19

FILTER HALT THRESHOLD ..................................................................................................................................................... 19

PROXIMITY THRESHOLD (LOW/HIGH) .................................................................................................................................... 19

AC FILTER ........................................................................................................................................................................ 19

HAND-HELD POWER ON DETECTION ...................................................................................................................................... 19

TOUCH THRESHOLD ............................................................................................................................................................ 19

8.3 OTP DETAILS: BANK 2 .......................................................................................................................................... 19

TARGET ........................................................................................................................................................................... 20

BASE VALUE ..................................................................................................................................................................... 20

FAILSAFE .......................................................................................................................................................................... 20

QUICK RELEASE ................................................................................................................................................................. 21

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IQS231 Datasheet v1.5

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USER INTERFACE ............................................................................................................................................................... 21

8.4 OTP DETAILS: BANK 3 .......................................................................................................................................... 23

PROJECTED SENSING .......................................................................................................................................................... 23

IO2 FUNCTION .................................................................................................................................................................. 23

IC MODE.......................................................................................................................................................................... 23

SAMPLE RATE ................................................................................................................................................................... 23

9 FULL PROGRAMMING REFERENCE .....................................................................................................................24

10 SPECIFICATIONS ................................................................................................................................................30

10.1 ABSOLUTE MAXIMUM RATINGS ............................................................................................................................... 30

11 PACKAGE INFORMATION ..................................................................................................................................33

11.1 TSOT23-6 ......................................................................................................................................................... 33

11.2 DEVICE PACKAGING CONVENTION ............................................................................................................................ 34

11.2.1 Top .......................................................................................................................................................... 34

11.2.2 Bottom .................................................................................................................................................... 34

11.3 MSL LEVEL ......................................................................................................................................................... 34

12 ORDERING AND PART-NUMBER INFORMATION ................................................................................................35

12.1 ORDERING INFORMATION ...................................................................................................................................... 35

12.2 DEVICE NUMBERING CONVENTION .......................................................................................................................... 35

13 REVISION HISTORY ............................................................................................................................................36

APPENDIX A CONTACT INFORMATION ..................................................................................................................37

ProxSense® Series

IQS231 Datasheet v1.5

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1 Summary: Packaging and Pin-Out

Figure 1.1 IQS231 pin-out (TSOT23-6 package)

Table 1.1 Pin-out description

IQS231 in TSOT23-6

Name

Type

Function

PRIMARY I/O

Digital Input/Output

Multifunction IO1 / SCL (I2C Clock signal)

VSS

Signal GND

SECONDARY I/O

/ Tx

Digital Input/Output

Multifunction IO2 / SDA (I2C Data output) /

VREG

Regulator output

Requires external capacitor

VDDHI

Supply Input

Supply:1.75V – 3.6V

Sense electrode

Connect to conductive area intended for

sensor

Table 1.2 Multifunction pin descriptions

Multifunction pin name

Multifunction pin option

IO1

Proximity output / Proximity output with heartbeat

IO2

Sensitivity input / Synchronization input /

Movement output / Touch output

Figure 1.2 IQS231 reference schematic

IQS

231

IO1 / SCL

VSS

IO2 / SDA / Tx

Cx / Rx

VDDHI

VREG

GND

220nF

GND

100pF

1uF

GND

VDDHI

GND

VIN

VDDHI

GND

470R

GND

VDDHI

Configure these resistors for IQS231 I2C operation.

PIN3: IQS231 SDA Pull-up

PIN1: IQS231 SCL Pull-up

4.7K

VDDHI

IO2/SDA

GND

IO1/SCL

IO2/SDA/TX

Optional: LED and current limiting resistor

PIN1: Output LED and current limiting resistor

on primary output

VDDHI

1.0K

DS1

BLUE

IO1/SCL

IO1/SCL IO1/SCL

IO1/SCL

IO2/SDA/TX

4.7pF

GND

LK1

2W-SLink Open

IO2/SDA/TX

IO1/SCL

VREG

CX/RX

VSS

VDDHI

IQS231

Option: Sensitivity input

GND for more sensitivity

Component Min Recommended Max

C1 180nF 220nF 330nF

C5 DNP 4.7pF

(Max recommended)

60pF

200pF

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IQS231 Datasheet v1.5

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2 Summary: One-Time-Programmable (OTP) options

OTP bank 0 IQS231 000000xx TSR

Bit7

Bit 0

Movement time-out

Movement threshold

Quick release threshold

Quick release beta

Prox no mov UI

00 - 2s

01 - 5s

10 - 10s

11 - Disabled (0s)

Prox&Mov UIs

00 - 10s

01 - 30s

10 - 60s

11 - 10min

00 – 4 counts

01 – 6

10 – 8

11 – 10

00 – moderate 100 counts

01 – strict 150

10 – relaxed 50

11 - very strict 250

00 – 2 (fast following)

01 - 3

10 - 4

11 – 5 (slow following)

OTP Bank 1 IQS231 0000xx00 TSR

Bit7

Bit 0

Filter halt

threshold

Proximity Threshold (low/high)

AC Filter

Hand-held

power on

detection

Touch threshold

0 – 3 counts

1 – 6

Filter halt

time-out fixed

at 5 seconds

Sensitivity input low / Sync input active / Mov

output / Touch output

0 – Increased

1 – Normal

0 – Disabled

1 – Enabled

00 – 32 counts

01 – 64

10 – 256

11 – 320

000 – 20 counts

001 – 28

010 – 36

011 – 44

100 – 52

101 – 68

110 – 68

111 – 132

Sensitivity input high (internal 20kΩ pull-up)

000 – 40 counts

001 – 56

010 – 72

011 – 88

100 – 104

101 – 136

110 – 195

111 – 264

OTP Bank 2 IQS231 00xx0000 TSR

Bit7

Bit 0

Reserved

Target

Base value

Failsafe

Quick

release

User interface

n/a

0 = 1200 /

1096

(movement)

1 = 768

00 – 100 counts

01 – 75

10 – 150

11 – 200

0 – Disabled

1 – Enabled

0 – Enabled

1 – Disabled

00 - Prox / No movement

01 - Prox with movement

10 - Prox with movement /

Touch with no movement

11 - Same as '10', touch output

forced on IO2

OTP Bank 3 IQS231 xx000000 TSR

Bit7

Bit 0

Reserved

Projected

sensing

IO2 function

IC mode

Reserved

Sample

rate

n/a

0 – Self

capacitance

1 – Projected

capacitance

00 - Sensitivity input (proximity

threshold adjust)

01 - Sync input

10 - Movement output

11 - Ignore input, no output

0 – Standalone

1 – I2C

Sample-to-sample time

(Response time) Includes 6

sample debounce burst of

24ms

0 – 30 Hz (57ms)

1 – 100 Hz (34ms)

Recommended base configurations: IQS128 replacement: IQS231 00000000 TSR | Full featured: IQS231 000A0600 TSR | Shared

electrode: IQS231 08000000 TSR | I2C mode (optional: jump to standalone): IQS231 04000000 TSR

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IQS231 Datasheet v1.5

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3 Summary: Programming reference (I2C memory map)

I2C Communications Layout

Address/

Command/

Byte

R/W

Default

Value

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

xxH

MAIN_EVENTS

n/a

DEBUG

SENSING

DISABLED

WARM

BOOT

COLD BOOT

RELEASE

TOUCH

PROX

Each read instruction returns ‘MAIN_EVENTS’ byte as first byte, followed by the data at the specified address

00H

PRODUCT_NUMBER

0x40

01H

SOFTWARE_VERSION

0x04

02H

DEBUG_EVENTS

n/a

RESERVED

ATI_ERROR

CH0_ATI

RESERVED

QUICK

RELEASE

EXIT MOV

DETECT

ENTER

MOV

DETECT

MOVEMENT

03H

EVENTS_ENABLED

R/W

0x03F

RESERVED

DEBUG

SENSING

DISABLED

WARM

BOOT

COLD BOOT

RELEASE

TOUCH

PROX

04H

COMMANDS

R/W

0x00

ATI_CH0

DISABLE

SENSING

ENABLE

SENSING

TOGGLE

AC FILTER

TOGGLE

MOVEMENT

ALGORITHM

TOGGLE ULP

MODE

TOGGLE

EVENT

MODE

WARM

BOOT

05H

OTP Bank 1

R/W

0x00

Filter halt

Proximity threshold

Read only

AC Filter

Hand-held

power on

detection

Touch threshold

Read only

06H

OTP Bank 2

R/W

0x00

RESERVED

Target

Base value

Failsafe

Quick release

User interface selection

07H

OTP Bank 3

R/W

0x00

RESERVED

Projected

sensing

IO2 Function

IC mode

(Standalone /

I2C)

RESERVED

Sample

rate

08H

QUICK RELEASE

R/W

0x00

Quick release threshold LUT

Quick release beta

0xC = 500

0xD = 750

0xE = 850

0xF = 1000

0x8 = 75

0x9 = 200

0xA = 300

0xB = 400

0x4 = 10

0x5 = 20

0x6 = 25

0x7 = 30

0x0 = 100

0x1 = 150

0x2 = 50

0x3 = 250

09H

MOVEMENT

R/W

0x30

(2s, 4)

Filter halt time

Movement threshold = (Value × 2) + 4

Available range: 4 – 34

0xC = 10min

0xD = 30min

0xE = 60min

0xF = 90min

0x8 = 30s

0x9 = 1min

0xA = 2min

0xB = 5min

0x4 = 4s

0x5 = 5s

0x6 = 10s

0x7 = 20s

0x0 = 0s

0x1 = 0.5s

0x2 = 1s

0x3 = 2s

0AH

TOUCH THRESHOLD

R/W

0x07

(32)

Touch threshold = (Value × 4) + 4

Available range: 4 – 1024

0BH

PROXIMITY

THRESHOLD

R/W

0x00

Reserved

Proximity threshold = (OTP value +1) x 4

x2 if IO2 is high in standalone

Available range: 20 – 132 (IO2 low)

Available range: 40 – 264 (IO2 high)

0CH

RESERVED

R/W

n/a

0DH

CH0 Multipliers

R/W

n/a

Reserved

CH0 Sensitivity Multiplier

CH0 Compensation multiplier

0 – 3

0 – 15

0EH

CH0 Compensation

R/W

n/a

0 – 255

0FH

CH1 Multipliers

R/W

n/a

Reserved

CH1 Sensitivity Multiplier

CH1 Compensation multiplier

0 – 3

0 – 15

10H

CH1 Compensation

R/W

n/a

0 – 255

11H

System flags

n/a

AC FILTER

ACTIVE

Reserved

CH1_ACTIVE

Reserved

CH0_LTA_HALTED

ATI_MODE

ZOOM MODE

12H

UI flags

n/a

Reserved

ULP_MODE

Reserved

HAND_HELD

PWR ON

QUICK_RELEASE

Reserved

OUTPUT

ACTIVE

13H

ATI flags

n/a

Reserved

14H

Event flags

n/a

CH1_ATI

ERROR

Reserved

CH1

MOVEMENT

CH0_ATI

ERROR

CH0

UNDEBOUNCED

CH0_ TOUCH

CH0_PROX

15H

CH0 ACF_H

n/a

Proximity channel: Filtered count value

0 – 2000

16H

CH0 ACF_L

n/a

17H

CH0 LTA_H

n/a

Proximity channel: Reference count value (Long term average)

0 – 2000

18H

CH0 LTA_L

n/a

19H

CH0 QRD_H

n/a

Proximity channel: Quick release detect reference value

0 – 2000

1AH

CH0 QRD_L

n/a

1BH

CH1 ACF_H

n/a

Movement channel: Filtered count value

0 – 2000

1CH

CH1 ACF_L

n/a

1DH

CH1 UMOV_H

n/a

Movement channel: Upper reference count value

0 – 2000

1EH

CH1 UMOV_L

n/a

1FH

CH1 LMOV_H

n/a

Movement channel: Lower reference count value

0 – 2000

20H

CH1 LMOV_L

n/a

21H

HALT_TIMER_H

n/a

Countdown timer to give active feedback on the time-out. Movement events will reset this timer

(0 – 255) × 100ms | Timer range: 0 – 90min

22H

HALT_TIMER_L

n/a

23H

TIMER.ATI_CH0

n/a

Countdown timer to give active feedback on the time until re-calibration is attempted after ATI-error

(0 – 255) × 100ms | Timer range: 0 – 25s

24H

TIMER.ATI_CH1

n/a

Countdown timer to give active feedback on the time until re-calibration is attempted after ATI-error

(0 – 255) × 100ms | Timer range: 0 – 25s

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IQS231 Datasheet v1.5

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4 Summary: Features

compatibility

Many older designs using the IQS128 will benefit from a “drop-in”

replacement on a production device for evaluation.

DYCAL / Quick release

A DYCAL-type implementation (referring to dynamic threshold

calibration) is recommended as main stability feature for the

latest SAR user interface. Passing the device SAR qualification

with this type of interface has been proven successful.

“Quick release” detection is the improved “DYCAL”-type

implementation and focusses on a release characteristic within a

time window.

Movement features add a second level of protection against stuck

conditions with the quick release detection.

The quick release will be detected on the proximity channel (not

the secondary movement channel) and the signal slope will be

monitored to enable the quick release. A single action from a

touch/proximity state will trigger the quick release event and the

event will only remain as long the proximity state holds.

User interface selection

The device offers 3 main UIs intended for SAR use. These are:

 Proximity UI, no continuous movement sensing

 Proximity UI, continuous movement sensing

 Proximity & touch UI, continuous movement sensing

during proximity, no movement sensing during touch (No

time-out during long duration stationary SAR tests)

In all cases the use of the quick release feature is recommended

to prevent typical non-human activations from remaining.

In all cases “no movement” and “movement sensing” refers to the

capacitive movement sensing during normal activation. “Hand held

detection” and “quick release” features will enable movement

sensing with a no-movement time-out, irrespective of which UI is

selected.

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Summary: Features (Continued 1…)

Movement detection

Movement detection is designed to function as human presence

detection in a localized area. This device can’t be used to fulfil an

accelerometer function (“G-sensor” function).

Human presence detection requires an exception in SAR testing

because the qualification testing only uses stationary “phantom

bodies”. Optimized human detection is offered through an integrated

separate channel, dedicated towards human detection.

Sensitivity

adjustment

Default input use: internal pull-up (20kΩ) by default, tie directly to

GND for more sensitive option.

Apart from the simple external adjustment, an external capacitor

is recommended for sensitivity adjustments. 1pF is considered a

small change in sensitivity, while 10pF changes are considered

large. A maximum of 60pF load is recommended for effective

proximity sensing.

Failsafe heartbeat

A single pulse of 500µs is integrated on IO1. This pulse is the

failsafe heartbeat, sent on each sensing event. This pulse will be

sent during the “stabilize time” as shown in Figure 8.1.

The failsafe indicator signal will precede the conversions

(sampling). The failsafe signal will be repeated during burst mode

in order to offer synchronization output to the master, indicating

exactly when sensitive measurements are done. Measurement

times have a fixed maximum which the user can implement.

The failsafe signal is disabled by default and may be enabled via

OTP option or I2C initialize with standalone setup.

Through I2C the IQS231 can be used in many different ways and the

configuration can be updated during later stages of development

than with the OTP route.

Switch I2C to standalone

Configure the device via a dedicated I2C type connection and switch

to any standalone mode for runtime operation. This minimises the

processor load and spurious content from communication signals.

The failsafe heartbeat is integral to detecting an unexpected reset

event. When the heartbeat disappears, default state is assumed and

the master device should reconfigure the device through I2C.

IQS

231

IO2

VDDHI

SENSITIVE

IO1

VREG

IQS

231

IO2

VDDHIVSS

LESS

SENSITIVE

IQS

231

IO2

VSS

VDDHIVSS

SENSITIVE

Cx Cx

IO1 IO1

VREG VREG

IO1

IQS

231

IO2

VDDHI

IO1

VREG

IQS

231

SDA

VDDHI

SCL

VREG

High

configurability

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Summary: Features (Continued 2…)

Self / Projected

Sensing

Projected is offered for future implementations with advantages in

proximity detection for SAR and on-ear. Electrode design is a

major design element in such application.

Projected sensing is permanently disabled when I2C mode is

chosen.

Hand-held detection

during power-on

Movement detection information will be used for power-on safety

detection. During the start-up period, the threshold detection

cannot be accurately used due to calibration at this time. Human

movement characteristics are used as an alternative.

A touch event is considered a more substantial indication of

actual threshold trigger and therefore this will clear the hand-held

detection state when a proximity & touch UI is selected.

Sync input

In order to ensure a stable sensing environment, sensing may be

done in strategic time windows controlled by a master device.

Automatic tuning

(ATI)

The Automatic tuning implementation (ATI) ensures optimal

sensitivity during runtime for various sensor environments.

Two channels are calibrated (proximity channel and movement

channel). Both run on the same Cx pin in different time slots.

An ATI-block time is defined to prevent re-ATI loops during touch

release events. The ATI-block is fixed for the movement channel,

and fixed for the standard touch/proximity channel

Reference signal

behaviour

Long-term-average (LTA: signal reference) behavior is optimized

for SAR where trigger tests are important in product qualification.

The LTA will therefore be slow while still able to prevent typical

temperature drift from causing activations.

Improved I2C

interface

Standard I2C polling for:

 Debugging & normal use

 Device polling optimized for guaranteed response (within

tCLK_stretch – clock stretching will be applied to the bus SCL

line)

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5 Features: Extended details

5.1 ATI (Automatic Tuning Implementation)

External sensor connections are calibrated in the following ways:

 Power On Reset (proximity channel is calibrated at each POR)

 Movement channel is only calibrated with POR when hand-held detection is enabled

 Proximity & movement channel is calibrated when the reference is out of bounds (1/8 of

target counts). The reference of the proximity channel is rapidly adapted when

capacitance moves away from the trigger threshold OR when an automatic “reseed” is

done (Reseed: reference = actual sensor value). The reference of the movement

channel is rapidly adapted in any direction of capacitive changes.

 Redo-ATI of the proximity channel can be initiated by the user in I2C mode using an I2C

command.

During each proximity channel ATI event, the proximity output is activated to indicate the event

and ensure a safe output during the event and in the case of an ATI-error.

Known issues: When 125 kHz charge transfer frequency selected for large capacitive and

resistive loads, the calibration has instability around the ATI boundaries.

5.2 Sensitivity adjustment

Apart from the simple external adjustment, an external capacitor is recommended for

sensitivity adjustments. 1pF is considered a small change in sensitivity, while 10pF changes

are considered large. A maximum of 60pF load is recommended for effective proximity

sensing.

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6 Recommended SAR configurations

Configuration name

Configuration

Details

IQS128 replacement

IQS231 00000000 TSR

Backwards compatible / with

quick release

Full-feature (base)

IQS231 000A0600 TSR

Touch threshold, Hand-held

power on detect, quick-

release, failsafe, prox&touch

UI,

Full-feature (no failsafe

heartbeat)

IQS231 00020600 TSR

Touch threshold, Hand-held

power on detect, quick-

release, prox&touch UI

Shared electrode

IQS231 08000000 TSR

Synchronization input

I2C Mode

IQS231 04000000 TSR

I2C enabled

See below sections for details on recommended configurations.

6.1 IQS128 replacement configuration

The IQS128 replacement mode is the default OTP configuration:

 DYCAL release is replaced with the quick release (enabled by default)

 The available input (IO2) may be used floating (has internal pull-up)

o Float / pull high: Less sensitive proximity threshold of 8 counts

o Shorting this pin to GND: More sensitive proximity threshold of 4 counts.

 The default base value of the IQS231 is decreased (100 compared to IQS128 @ 200)

to give more sensitivity for a lower target count

o add a larger Cx capacitance if this sensitivity boost is applied in an environment

with a low signal-to-noise ratio.

 The default quick release settings make the feature function towards the safe side. A

design with 20mm trigger distance should activate the feature if a quick release action

is done from a deep touch on the electrode.

 Reference part number: IQS231 00000000 TSR

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6.2 Full feature configuration

With the standalone mode using movement, all important features of the IQS231 are

recommended to enable:

 Enable hand held detection: This feature offers improved user protecting when

powering up the device in-hand.

 Enable failsafe output: This feature will place short pulses on the output which can

easily be ignored by a debounce algorithm and detected by an interrupt. When failsafe

pulses disappear, the output IQS231 output should be ignored and the device should

enter a safe state.

 Enable the proximity & touch UI with movement. This UI will effectively time-out when

a proximity state is activated, but with no user interaction (device placed on table / in

bag etc.). When in a touch state, no time-out will occur. This time-out blocking is

beneficial for the long term SAR qualification testing.

 When the touch UI is enabled the touch level becomes active. Select a touch threshold

 Keep quick release enabled. The feature will improve user experience with a quick 2

second no-movement time-out. The time-out is fixed (2 sec) when any proximity &

movement UI is chosen.

 Reference part number: IQS231 000A0600 TSR (or IQS231 00020600 TSR no

failsafe heartbeat)

6.3 Shared electrode with RF antenna

When using the device in an advanced implementation using the RF antenna as sensing

electrode, the following settings are recommended:

 Enable the synchronization input to take control of when sensing is allowed (pull IO2

low) and when sensing is paused (IO2 high with internal pull-up). This feature may be

used to multiplex RF transmit, receive and capacitive sensing. Sensing requires a

minimum IO2 low time of 10ms to do a proper charge transfer. The proximity threshold

will default to the low option.

 Use the mode described next: “I2C setup with standalone output in runtime”. This mode

will ensure full control of settings while offering a connection to the RF module without

the frequency harmonics produced by I2C communications.

 Reference part number: IQS231 08000000 TSR

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6.4 I2C setup with standalone output in runtime

For full control of the settings, an I2C device may be used (I2C enabled with OTP) to do the IC

setup, while runtime offers a standalone output. The advantage is that detailed settings can be

flexible and determined separately from the procurement phase (OTPs are required to be fixed

early enough to satisfy the lead-time for an OTP-specific solution). Details about this mode are

as follows:

 From about 20ms from power-up, the device may be polled by address.

 The device will acknowledge the correct address within about 5ms from any R/W event

(expect clock stretching during IQS231 wake-up)

 Send write commands via I2C until all the required settings are written

 Send the mode switch bit “IC mode” -> “Standalone” only after all settings are written.

After writing this setting, the next I2C stop sent will automatically instruct a soft reset to

put the IC in standalone mode, keeping all the settings written through I2C. A soft reset

will also ensure that a recalibration is done.

 Quick reference to switch modes: Clear register 0x07 (OTP Bank 3) bit 2 to enter

standalone mode.

 Reference part number: IQS231 04000000 TSR

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7 I2C Programming Guide (Summary)

The IQS231 device interfaces to a master controller via a 2-wire (SDA and SCL) serial

interface bus that is I2CTM compatible, with a maximum communication speed of 400kbit/s.

The protocol acknowledges an address request independently. The I2C hardware module is

awake for address recognition while the IQS231 is in sleep mode, giving the ability to wake the

device at any time and effectively communicate via serial interface. This is different compared

to other ultra-low power Azoteq solutions where the communications module also sleeps

during standard IC sleep times. Repeated polling requests where required in such case.

7.1 Add I2C connection

When using I2C mode, ensure the connections as shown in Figure 1.1. Internal pull-up

resistors are sufficient for communication speeds up to 100kbits/s with low capacitance on the

lines (<15pF). For 400kbit/s, be sure to place pull-up resistors (4.7kΩ recommended)

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7.2 I2C command structure

By writing to address 0x04, commands can be sent to the device. The commands are as

follows:

Table 7.1 I2C command structure

Reg 0x04 Bit

Name

Description

Toggle (yes/no)

WARM BOOT

Soft reset, all

registers remain as

written, UI resets

RESERVED

n/a

ULP MODE

Ultra low power mode

enable (512ms)

Yes

RESERVED

n/a

AC FILTER

Toggle between

option available in

OTP

Yes

DISABLE SENSING

Disables all

conversions

ENABLE SENSING

Enable capacitive

sensing

ATI CH0

Perform re-calibration

on proximity channel

7.3 Control Byte

The Control byte indicates the 7-bit device address (44H default) and the Read/Write indicator

bit. The structure of the control byte is shown in Figure 7.1.

R/W

1 0 0 0 1

MSB LSB

7 bit address

I2C Group Sub- addresses

0 0

Figure 7.1 IQS231 control byte

The I2C device has a 7 bit Slave Address (default 0x44H) in the control byte as shown in

Figure 7.1. To confirm the address, the software compares the received address with the

device address. Sub-address values can be set by OTP programming options.

The IQS231 has no alternate slave address options.

7.4 Test mode (address 0x45)

During the power-on period (approx. 20ms), the device will respond to polling requests on

address 0x45 (test-mode address). Test-mode is used during IC production and OTP

configuration.

With another device on the I2C bus with address 0x45, power-up sequence and

communication timing should be considered.

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7.5 I2C typical setup

The typical I2C setup would adjust the following registers:

 Quick release beta

 Quick release threshold

 Movement threshold

 Touch threshold

 Proximity threshold

 Filter halt time

 User interface

 IC mode

The rest of the settings will only require adjustment with specific requirement.

7.6 I2C read (Event register)

Each I2C read will always return the event register as the first byte. When reading from a

specific register (write address before read), 2x reads should be done. See memory map first

line for detail on the event register.

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8 Configuration Options

The IQS231 offers various user selectable options. These options may be defined via I2C

setup or one-time programmable (OTP) configuration. OTP configured devices may be

ordered pre-programmed for bulk orders or in-circuit programming techniques may be

implemented during the product testing phase. I2C setup allows access to all device settings

while entering direct output mode when selected by the MCU.

Azoteq offers a Configuration Tool (CT210 or later) and associated software that can be used

to program the OTP user options for prototyping purposes. For further information regarding

this subject, please contact your local distributor or submit enquiries to Azoteq at:

ProxSenseSupport@azoteq.com

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8.1 OTP Details: Bank 0

Movement time-

out

(bit 7:6)

When no movement is detected within a time period, a movement

time-out occurs. The reference is halted until the timer clears. After

the timer clears, the reference signal is made equal to the actual

signal, nullifying any signal delta that may have caused a proximity

or touch event. The timer is reloaded with every movement event

detected.

Movement

threshold

(bit 5:4)

A low count threshold region is defined for a movement signal

internally stored. Movement characteristics accumulate and triggers

as soon as it reaches the threshold. The accumulated effect is

nullified and accumulation is restarted in order to detect the next

possible movement event.

Quick release

threshold

(bit 3:2)

The quick release feature will operate according to the parameters

as specified in:

 DYCAL / Quick release definition

 Quick release beta

 Quick release threshold

The quick release threshold defines the trigger point for the feature

where the counts deviate from a quick release moving average in a

certain direction. The direction is determined by the projected

sensing enabled/disabled bit:

 With projected disabled (default) the direction is with

increasing counts

 With projected enabled the direction is with decreasing

counts

Quick release

beta

(bit 1:0)

The quick release beta forms part of the quick release feature and is

the filter intensity of the reference value which follows the actual

counts. The quick release is triggered according to the difference

between this reference value and the actual counts.

When this value is large, the quick release will trigger for a variety of

release types from slow to fast releases.

When this value is small, the quick release will only trigger for fast

releases.

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8.2 OTP Details: Bank 1

Filter halt

threshold

(bit 7)

The filter halt is a separate threshold that is intended to be more sensitive

than the proximity threshold. While in no proximity detected state, the

reference of the IQS231 will follow the actual signal to prevent

environmental effects such a temperature drift. A filter halt feature is

implemented to “freeze” the reference and allow slow proximity trigger

approaches to still be effective without adapting.

The time-out is tfilter_halt when a filter halt does not result in a proximity event.

Proximity

Threshold

(low/high)

(bit 6:4)

By default this is the only trigger threshold in the system (touch also

threshold available).

The threshold is adjustable in actual counts values (count values can be

seen when streaming I2C value through the IQS231 GUI). The threshold is

the amount of counts the actual signal falls below (projected disabled) |

rises above (projected enabled) the reference signal (long-term average)

In the default configuration the input pin IO2 will be active. IO2 = VSS will

enable the chosen option in the OTP (20-132 counts) IO2 = VDDHI (40-

264 counts)

The system will default to the IO2 = VSS option when sync input or

movement output is enabled.

AC Filter

(bit 3)

Incoming samples are filtered by default. This option gives the ability to

significantly decrease the filter strength. Default is an IIR (infinite impulse

response) filter of 2 (23). This “increased” option enables an IIR filter of 8

(23). The filter can be changed to 21 by setting this bit.

Hand-held

power on

detection

(bit 2)

Standalone operation involves the detection of user interaction (movement)

during power-on. When enabled, the slightest interaction detected during

tpwrcheck will result in a safe output along with resetting the timer that times

out at tpwrcheck. This allows for a safe period during power-up before starting

with normal threshold based sensing.

The “movement” parameters used for this feature will be as follows:

 tpwrcheck = “Movement time-out” when UI is set to any proximity with

movement selection

 tpwrcheck = 5 seconds when UI is set to proximity with no movement

enabled

 Movement trigger threshold = Movement threshold register

 Filtering = AC Filter bit

Touch

threshold

(bit 1:0)

Threshold in counts that defines the level below the proximity threshold that

cancels a quick release event and disables any active movement detection.

8.3 OTP Details: Bank 2

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Target

(bit 6)

The target count is an offset value of the actual system capacitance. The

actual signal (expressed in counts) will be calibrated as close as

possible to this value.

A larger target optimizes sensitivity at the cost of charge transfer time. A

lower target offers more stability, but less sensitivity.

Base value

(bit 5:4)

The base value is a lower target value for the actual signal and implies

the system gain. A base value of 100 and target of 1000 implies a x10

gain, while base value of 200 and target of 1000 implies a x5 gain.

Failsafe

(bit 3)

This bit is only has an effect when User interface is set to Standalone.

Default is to always have 500us pulses on output, separated by the

sampling period. A pulse will be on output every time a capacitive

conversion is done. Conversion rate and debounce events may be

debugged through this output.

Figure 8.1 Conversion signal on Cx timing description

Figure 8.2 Conversion diagram with failsafe output signal

Scan time

Sample time

Response (standalone)

Sleep time

Crx1

(touch

& prox) Crx1

(movement)

Stabilize time

Normal conversion rate Burst mode to debounce

proximity event

No prox Prox detected

IO1

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OTP Details: Bank 2 (...continued)

Quick

release

(bit 2)

The quick release feature can be disabled here. It is enabled by default.

The quick release feature offers improved user experience and does not

influence trigger testing. The feature is mainly directed at SAR applications, but

also has significant benefits for on-ear detection applications.

The touch depth and speed of release is used to detect the instance where the

user interaction implies a release condition. This is required for cases where

the normal threshold release is not triggered for any of the following reasons:

 Device placed on table while releasing the hand (the capacitive

influence of the table remains)

 Place device inside a bag while releasing the hand (the capacitive

influence of the bag remains)

 Fit a protective cover during use (the capacitive influence of the cover

remains)

 Extreme temperature (cool down) shift causes a shift in capacitive

environment

 Capacitance impulse recovery (drop test, transient bursts etc)

User

interface

(bit 1:0)

When movement Uis are enabled, the timeout is only active in the proximity

region. When in touch, only quick release can get the IC out of a stuck

condition. In such case no movement time-out for quick release is fixed at 2sec

and no-movement time-out for proximity is as defined in OTPs

Figure 8.3 Proximity UI no movement

POR

Hand held detect

Proximity Active

Quick release

active &

Proximity Active

Filter halt

Idle

Prox clear

Redo ATI

Prox active

ATI error

Prox active

Proximity Active

QR detect

Prox detect

5sec !Mov

2sec !Mov

Normal

prox

release

5sec

no prox

HH detect

enabled

Reference (LTA)

out-of-bounds

POR auto-ATI

calibration

complete

No calibration

convergence

10 sec

time-out

Mov

detect

5sec

!Mov

Disable HH

detect

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OTP Details: Bank 2 (...continued)

User

interface

(bit 1:0)

(continued..)

Figure 8.4 Proximity UI with movement

User

interface

(bit 1:0)

(continued..)

Figure 8.5 Proximity & touch UI (with movement enabled in proximity & movement

disabled in touch)

POR

Hand held detect

Proximity Active

Quick release

active &

Proximity Active

Filter halt

Idle

Prox clear

Redo ATI

Prox active

ATI error

Prox active

Proximity Active

QR detect

Prox detect

5sec !Mov

2sec !Mov

Normal

prox

release

5sec

no prox

x sec

!Mov

HH detect

enabled

Reference (LTA)

out-of-bounds

POR auto-ATI

calibration

complete

No calibration

convergence

10 sec

time-out

Mov

detect

5sec

!Mov

Disable HH

detect

POR

Hand held detect

Proximity Active

Touch Active

Quick release

active &

Proximity Active

Filter halt

Idle

Prox clear

Redo ATI

Prox active

ATI error

Prox active

Proximity Active

Touch

detect

Normal

touch

release

QR detect

Touch detect

QR cancelled

Prox detect

5sec !Mov

2sec !Mov

Normal

prox

release

5sec

no prox

x sec

!Mov

HH detect

enabled

Reference (LTA)

out-of-bounds

POR auto-ATI

calibration

complete

No calibration

convergence

10 sec

time-out

Mov

detect

5sec

!Mov

Disable HH

detect

Touch detect

Disable HH detect

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8.4 OTP Details: Bank 3

Projected

sensing

(bit 5)

When disabled (default) self-capacitance technology is used. When enabled,

projected capacitance technology is used. In this case Input (IO2) becomes

a transmit signal and the Cx pin (pin 6) becomes the receive pin. In this

mode any other I/O function defined on IO2 will be cancelled automatically.

IO2

function

(bit 4:3)

By default IO2 will be a sensitivity adjustment input. An internal pull-up

(Rinternal) will by default select a less sensitive option (IO2 = VDDHI). By

strapping then pin directly to Vss, a more sensitive option is selected (IO2 =

VSS).

When the movement output is enabled, the input defaults to the “more

sensitive option” as shown with IO2 = VSS

With the output enabled the movement events are shown on IO2. The output

is in an active low, open drain configuration. The output will remain low for

tawake when movement is detected and this will occur during the sample time

after the movement trigger occurs (the movement trigger is delayed with the

sample rate)

Sync input:

The input (pin IO2) may be used to detect when to sense and when to halt

the sensing.

Figure 8.6 Sync input of the IQS231

IC mode

(bit 2)

Standalone (default), or I2C

The advantage of this option is explained in the Switch I2C to standalone

section of the features summary.

Sample rate

(bit 1:0)

The various sample rates offered are mainly given for the user to determine

an ideal balance between power consumption and response time. Overall

response times of the IQS231 are improved with SAR trigger testing in mind.

IQS

231

IO1

VSS

IO2

VDDHI

VREG

VDDHI

0V SYNC PULSE SYNC PULSE

MCU

GPIO

SYNC PULSE SYNC PULSE

Startup time

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9 Full programming reference

A detailed list of the I2C registers follows and follows the structure of the memory map

summary on page 6.

ADDR

Bit

Description

xxH

MAIN_EVENTS

n/a

DEBUG – Debug events are disabled by default. In order to

report debug events, enable debug events in register 0x03 and

read debug event in register 0x02 when this bit is set.

SENSING DISABLED – An indication of forced or implied times

when no sensing signals are applied to the sense pin. When this

bit is set and bit 2 is cleared, sensing is disabled. When this bit

and bit 2 is set, sensing is enabled again.

WARM BOOT – A software reset command in register 0x04 will

lead to a warm boot. This will imply a reset for the user

interface, re-calibration, and hand-held power on detection will

be forced if enabled.

COLD BOOT – A hard reset (power supply cycle) will cause all

registers to return to a default value. This indicator will imply the

need to re-initialize the device.

RELEASE – A touch, prox or sensing event may be paired with

a release indication to show an exit of the flagged event.

TOUCH – Disabled by default, this bit will be active when a

touch and prox user interface is chosen.

PROX - The main feedback bit to indicate an activation

00H

PRODUCT_

NUMBER

n/a

The product number is fixed at 0x40

01H

SOFTWARE_

VERSION

n/a

The only software version released is 0x04

02H

DEBUG_

EVENTS

n/a

ATI_ERROR – when a recalibration cannot converge, due to

external tampering or instability, this bit will indicate the error

and implies that the calibration does not offer optimal sensitivity.

The PROX event in the main events register will be set along

with this bit in such case.

CH0_ATI – An indication that a recalibration of the proximity

sensing channel has occurred. With calibration, the PROX

output in main events will be set and after calibration, the PROX

output will release.

n/a

QUICK RELEASE – The quick release feature is a single event

that is indicated here. This event will always imply an “ENTER

MOV DETECT”, but is not the only event that causes movement

detection to be activated.

EXIT MOV DETECT – The user interface dictates when the

movement channel is deactivated. The deactivation of

movement sensing will be reported in this bit.

ENTER MOV DETECT – Movement detection is user interface

dependant and not continually active. Movement detection

implies that a separate movement channel is activated. This

activation will be reported in this bit.

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ADDR

Bit

Description

MOVEMENT – Each trigger detected by the movement

algorithm is reported as an event that resets along with each

read operation.

03H

EVENTS_ENAB

LED

n/a

ENABLE (set) or DISABLE (clear) events that are reported in

the MAIN_EVENTS register. Each read operation is preceded

by the MAIN_EVENTS byte.

The bit order from the MAIN_EVENTS register can be used to

determine a required event mask

04H

COMMANDS

ATI_CH0 – Recalibrate the proximity channel. Only after closing

the communications window, a recalibration of the proximity

sensing electrode will be started.

DISABLE SENSING – Sensing can be disabled to save power

or synchronize sensing in a more complex system and limit

certain signals from affecting the measurement.

ENABLE SENSING – Sensing can be enabled at strategic times

to limit interference in the sensitive measurement environment.

ENABLE / DISABLE sensing will be reflected in the

MAIN_EVENTS register. ENABLE sensing will result in a

“SENSING DISABLED” and “RELEASE” bit being set

simultaneously.

TOGGLE AC FILTER – The AC Filter as defined in OTP Bank

1 can be toggled through a command and read in register 0x05

(OTP Bank 1)

RESERVED

TOGGLE ULP MODE - An ultra low power mode is defined to

limit power consumption to a maximum with a 512ms sensing

period. The IQS231 debounce will give a sub-550ms response

time.

RESERVED

WARM BOOT – A warm boot implies a user interface restart

while keeping all register changes made. Sending the command

will execute as soon as the communications window is closed.

The event will be flagged in the MAIN_EVENTS register.

05H

OTP Bank 1

Filter halt threshold (see OTP bank definition)

Proximity Threshold (low/high) read only

For reading OTP setting only. Note that the actual proximity

threshold is defined in register 0x0B.

AC Filter (see OTP bank definition)

Hand-held power on detection (see OTP bank definition)

Touch threshold (read only)

For reading OTP setting only. Note that the actual touch

threshold is defined in register 0x0A.

06H

OTP Bank 2

Reserved

Target (see OTP bank definition)

Base value (see OTP bank definition)

Failsafe (see OTP bank definition)

Quick release (see OTP bank definition)

User interface (see OTP bank definition)

07H

OTP Bank 3

RESERVED

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ADDR

Bit

Description

RESERVED

Projected sensing (see OTP bank definition)

IO2 function (see OTP bank definition)

IC mode – I2C or standalone. This powerful feature enables the

designer to configure the device in I2C mode and thereafter

reduce the I2C overhead and related EMI by switching to

standalone for runtime. The actual mode switch occurs as soon

as the communications window is closed with a stop command.

It is recommended to enable the failsafe heartbeat when going

from I2C mode to standalone. The absence of the heartbeat

should be used to indicate an unexpected reset event, implying

the need for I2C reconfiguration.

Sample rate (see OTP bank definition)

08H

QUICK

RELEASE

The OTP options for quick release (see Quick release threshold

in OTP Bank 0) is extended in I2C mode to enable a very

specific release characteristic.

Quick release threshold look-up table:

0x0 = 150 counts

0x1 = 100

0x2 = 50

0x3 = 250

0x4 = 10

0x5 = 20

0x6 = 25

0x7 = 30

0x8 = 75

0x9 = 200

0xA = 300

0xB = 400

0xC = 245

0xD = 230

0xE = 335

0xF = 500

Quick release beta – This beta value is an indication of the filter

strength used to track the characteristic of the release signal.

The faster the tracking, the less likely the release will be

detected (only very quick events will be detected). The slower

the tracking, the more likely the quick release occur (quick

events and slow events will be detected as a quick release)

Practical values for the beta range between:

0 (fast events only) and

4 (fast and slow events)

The maximum of 0xF is impractical and high values are not

recommended.

09H

MOVEMENT

MOVEMENT TIME-OUT – Depending on the user interface, a

movement detection channel may be started along with specific

events (proximity / quick release).

The timer is set and cleared as mentioned in Movement time-

out (OTP Bank 0).

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ADDR

Bit

Description

No movement time-out value:

0x0 = 0s

0x1 = 0.5s

0x2 = 1s

0x3 = 2s

0x4 = 4s

0x5 = 5s

0x6 = 10s

0x7 = 20s

0x8 = 30s

0x9 = 1min

0xA = 2min

0xB = 5min

0xC = 10min

0xD = 30min

0xE = 60min

0xF = 90min

MOVEMENT THRESHOLD.

Movement threshold = (Value × 2) + 4

Available range: 4 – 34

For description see Movement threshold in OTP Bank 0.

Note that the movement threshold in OTP Bank 1 is loaded in

this register at start up and the OTP setting becomes read only.

All movement threshold adjustments are performed in this

0AH

TOUCH

THRESHOLD

n/a

Touch threshold = (Value × 4) + 4

Available range: 4 – 1024

For details on the touch threshold operation and uses see

Touch threshold in OTP Bank 1.

Note that the touch threshold in OTP Bank 1 is loaded in this

touch threshold adjustments are performed in this register.

0BH

PROXIMITY

THRESHOLD

Reserved

Proximity threshold = (OTP value +1) x 4

x2 if IO2 is high in standalone

Available range: 20 – 132 (IO2 low)

Available range: 40 – 264 (IO2 high)

For details on the proximity threshold operation and uses see

Proximity Threshold (low/high) in OTP Bank 1.

Note that the proximity threshold in OTP Bank 1 is loaded in this

proximity threshold adjustments are performed in this register.

0CH

RESERVED

n/a

0DH

CH0 Multipliers

Reserved

CH0 Sensitivity Multiplier (Values: 0 – 3)

CH0 Compensation multiplier (Values: 0 – 15)

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ADDR

Bit

Description

0EH

CH0

Compensation

n/a

0 – 255

0FH

CH1 Multipliers

Reserved

CH1 Sensitivity Multiplier (Values: 0 – 3)

CH1 Compensation multiplier (Values: 0 – 15)

10H

CH1

Compensation

n/a

0 – 255

11H

System flags

AC FILTER ACTIVE – Indicates if the function selected in

Reserved

CH1 ACTIVE – Indicates if the movement channel (CH1) is

activated and busy with movement detection

Reserved

CH0 LTA HALTED – Indicates that some proximity shift has

been detected according to the threshold in register 0x05 bit 7.

This event automatically clears if a proximity is not detected

within tfilter_halt

ATI MODE – Indicates that CH0 or CH1 is busy with the

recalibration routine. Read the ATI in flags in register 0x13 for

more information

ZOOM MODE – At each threshold of the proximity channel

(proximity & touch threshold), a signal “debounce” is done

rapidly. During this rapid event, this bit will be set.

12H

UI flags

Reserved

ULP MODE – When ULP mode is entered by the command in

Reserved

Hand held power on – Indicates the hand held power on feature

is active/inactive after power on or WARM BOOT.

Quick release – Indicates when a quick release action has been

detected

Reserved

Output active – Indicates an active proximity detection

13H

ATI flags

n/a

Reserved

14H

Event flags

CH1_ATI ERROR – This will indicate that the movement

channel is not operating under optimal sensitivity and the

calibration will automatically be redone in tredoATI. The count-

down time until next attempt can be read in register 0x25 and

0x26.

Reserved

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ADDR

Bit

Description

CH1 MOVEMENT

CH0_ATI ERROR – Because of external interference, strong

EMI or extreme capacitive load conditions the calibration will not

be able to reach the target sensitivity (target count – as defined

in register 0x06 bit 6). The proximity output will be set in such

case in order to fail towards the safe side. The calibration will

automatically be redone in tredoATI. The count-down time until

next attempt can be read in register 0x23 and 0x24.

CH0 UNDEBOUNCED – An indication that a proximity event

has been detected before a debounce operation has been done.

CH0_ TOUCH – The touch event is flagged here for the

duration of the touch

CH0_PROX – The proximity event is flagged here for the

duration of the proximity

15H

CH0 ACF_H

n/a

Proximity channel: Filtered count value

0 – 2000

This count value is related to an offset actual capacitive load.

The offset is done though calibration and ensures system

sensitivity.

16H

CH0 ACF_L

17H

CH0 LTA_H

n/a

Proximity channel: Reference count value (Long term average)

0 – 2000

18H

CH0 LTA_L

19H

CH0 QRD_H

n/a

Proximity channel: Quick release detect reference value

0 – 2000

1AH

CH0 QRD_L

1BH

CH1 ACF_H

n/a

Movement channel: Filtered count value

0 – 2000

1CH

CH1 ACF_L

1DH

CH1 UMOV_H

n/a

Movement channel: Upper reference count value

0 – 2000

1EH

CH1 UMOV_L

1FH

CH1 LMOV_H

n/a

Movement channel: Lower reference count value

0 – 2000

20H

CH1 LMOV_L

21H

HALT_TIMER_

n/a

Countdown timer to give active feedback on the time-out.

Movement events will reset this timer

(0 – 255) × 100ms | Timer range: 0 – 90min

22H

HALT_TIMER_

23H

TIMER.ATI_CH

n/a

Channel 0 countdown timer to give active feedback on the time

until re-calibration is attempted after ATI-error

(0 – 255) × 100ms | Timer range: 0 – 25s

24H

TIMER.ATI_CH

n/a

Channel 1 countdown timer to give active feedback on the time

until re-calibration is attempted after ATI-error

(0 – 255) × 100ms | Timer range: 0 – 25s

ProxSense® Series

IQS231 Datasheet v1.5

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10 Specifications

10.1 Absolute maximum ratings

The following absolute maximum parameters are specified for the device:

Exceeding these maximum specifications may cause damage to the device.

 Operating temperature -40°C to 85°C

 Supply Voltage (VDDHI – VSS) 3.6V

 Maximum pin voltage VDDHI + 0.5V (may not

exceed VDDHI max)

 Maximum continuous current (for specific Pins) 10mA

 Minimum pin voltage VSS – 0.5V

 Minimum power-on slope 100V/s

 ESD protection ±8kV (Human body model)

 Package Moisture Sensitivity Level (MSL) 1

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Table 10.1 IQS231 General Operating Conditions

DESCRIPTION

Conditions

PARAME

TER

MIN

TYP

MAX

UNIT

Supply voltage

VDDHI

1.75

n/a

3.6

Internal regulator output

1.75 ≤ VDDHI≤

3.6

VREG

1.62

1.65

1.72

Default Operating Current

3.3V, Scan time

= 30ms

IIQS231LP30

μA

Full Power Setting

3.3V, Scan time

=9ms

IIQS231FP

μA

Halt charge

Table 10.2 Start-up and shut-down slope Characteristics

DESCRIPTION

Conditions

PARAMETER

MIN

MAX

UNIT

Power On Reset

VDDHI Slope ≥ 100V/s

@25°C

POR

1.2

1.6

Brown Out Detect

VDDHI Slope ≥ 100V/s

@25°C

BOD

1.15

1.6

Table 10.3 Various IQS231 characteristics

DESCRIPTION

MIN

TYP

MAX

UNIT

tcomms_timeout

tCLK_stretch

tfilter_halt

tpwrcheck

tredoATI

tawake

Rinternal

kΩ

fsampling

500

kHz

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Table 10.4 Digital input trigger levels

DESCRIPTION

Conditions

PARAMETER

MIN

TYPICAL

MAX

UNIT

All digital inputs

VDDHI = 3.3V

Input low level

voltage

1.19

1.3

All digital inputs

VDDHI = 1.8V

Input low level

voltage

0.54

0.6

0.76

All digital inputs

VDDHI = 1.8V

Input high level

voltage

0.9

1.0

1.2

All digital inputs

VDDHI = 3.3V

Input high level

voltage

1.90

2.1

2.20

Table 10.5 Digital output levels

DESCRIPTION

Conditions

PARAMETER

@1mA*

@10mA*

UNIT

Output voltage low

VDDHI = 3.3V

VOL

0.01

0.1

Output voltage high

VDDHI = 3.3V

VOH

n/a**

* Current sinked into output pin

** Only open drain output offered. Pull-up resistor to VDDHI recommended

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11 Package information

11.1 TSOT23-6

Figure 11.1 TSOT23-6 Packaging

Table 11.1 TSOT23-6 Dimensions

Dimension

Min (mm)

Max (mm)

2.60

3.00

1.50

1.70

2.80

3.00

0.30

0.50

0.95 Basic

0.84

1.00

0.00

0.10

0.30

0.50

0°

8°

0.03

0.20

Drawing not on Scale

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11.2 Device packaging convention

11.2.1 Top

231 xx

IC NAME

BATCH

CODE

IC name

231

Batch

11.2.2 Bottom

No bottom marking present

11.3 MSL Level

Moisture Sensitivity Level (MSL) relates to the packaging and handling precautions for some

semiconductors. The MSL is an electronic standard for the time period in which a moisture

sensitive device can be exposed to ambient room conditions (approximately 30°C/85%RH see

J-STD033C for more info) before reflow occur.

Package

Level (duration)

TSOT23-6

MSL 1 (Unlimited at ≤30 °C/85% RH)

Reflow profile peak temperature < 260 °C for < 30 seconds

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12 Ordering and Part-number Information

12.1 Ordering Information

Please check stock availability with your local distributor.

CONFIGURATION zzzzzzzz = IC configuration (hexadecimal)

Default 00000000 (other configurations

available on request)

PACKAGE TYPE TS = TSOT23-6 package

BULK PACKAGING R = Reel (3000pcs/reel) – MOQ = 3000pcs

MOQ = 1 reel (orders shipped as full reels)

Example ordering code for default device: IQS231 00000000 TS R

12.2 Device Numbering Convention

REVISION x = IC Revision Number

TEMPERATURE RANGE t = -40°C to 85°C (Industrial)

DATE CODE P = Internal use

WWYY = Batch number

Figure 12.1 TSOT23-6 Tape Specification

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13 Revision History

Revision Number

Description

Date of issue

v1.0

IC release version

12 August 2015

v1.1

Figure 1.2 updated – load capacitor moved

AC filter is increased by default

Large quick release thresholds adapted

Known issues and workarounds:

Proximity threshold

Low frequency sensing mode omission

9 October 2015

V1.2

Typing error on proximity threshold OTP in

bank1 should be 110 – 195 not 136

V1.3

Device package marking detail added

13 November 2015

V1.4

Output voltage levels added

8 March 2016

V1.5

Example schematic updated with C1 capacitor

guide added

Low power references removed

4 May 2016

ProxSense® Series

IQS231 Datasheet v1.5

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Appendix A Contact Information

USA

Asia

South Africa

Physical

Address

6507 Jester Blvd

Bldg 5, suite 510G

Austin

TX 78750

USA

Rm2125, Glittery City

Shennan Rd

Futian District

Shenzhen, 518033

China

109 Main Street

Paarl

7646

South Africa

Postal

Address

6507 Jester Blvd

Bldg 5, suite 510G

Austin

TX 78750

USA

Rm2125, Glittery City

Shennan Rd

Futian District

Shenzhen, 518033

China

PO Box 3534

Paarl

7620

South Africa

Tel

+1 512 538 1995

+86 755 8303 5294

ext 808

+27 21 863 0033

Fax

+1 512 672 8442

+27 21 863 1512

info@azoteq.com

linayu@azoteq.com.cn

info@azoteq.com

Please visit www.azoteq.com for a list of distributors and worldwide representation.

The following patents relate to the device or usage of the device: US 6,249,089 B1; US 6,621,225 B2; US 6,650,066 B2;

US 6,952,084 B2; US 6,984,900 B1; US 7,084,526 B2; US 7,084,531 B2; US 7,265,494 B2; US 7,291,940 B2; US 7,329,970 B2;

US 7,336,037 B2; US 7,443,101 B2; US 7,466,040 B2 ; US 7,498,749 B2; US 7,528,508 B2; US 7,755,219 B2; US 7,772,781

B2; US 7,781,980 B2; US 7,915,765 B2; US 7,994,726 B2; US 8,035,623 B2; US RE43,606 E; US 8,288,952 B2; US 8,395,395

B2; US 8,531,120 B2; US 8,659,306 B2; US 8,823,273 B2; EP 1 120 018 B2; EP 1 206 168 B1; EP 1 308 913 B1; EP 1 530 178

A1; EP 2 351 220 B1; EP 2 559 164 B1; CN 1330853; CN 1783573; AUS 761094; HK 104 1401

IQ Switch®, SwipeSwitch™, ProxSense®, LightSense™, AirButtonTM, ProxFusion™, Crystal Driver™ and the

logo are trademarks of Azoteq.

The information in this Datasheet is believed to be accurate at the time of publication. Azoteq uses reasonable effort to maintain the information up-to-date and accurate, but does not warrant

the accuracy, completeness or reliability of the information contained herein. All content and information are provided on an “as is” basis only, without any representations or warranties, express

or implied, of any kind, including representations about the suitability of these products or information for any purpose. Azoteq disclaims all warranties and conditions with regard to these

products and information, including but not limited to all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement of any third party

intellectual property rights. Azoteq assumes no liability for any damages or injury arising from any use of the information or the product or caused by, without limitation, failure of performance,

error, omission, interruption, defect, delay in operation or transmission, even if Azoteq has been advised of the possibility of such damages. The applications mentioned herein are used solely

for the purpose of illustration and Azoteq makes no warranty or representation that such applications will be suitable without further modification, nor recommends the use of its products for

application that may present a risk to human life due to malfunction or otherwise. Azoteq products are not authorized for use as critical components in life support devices or systems. No

licenses to patents are granted, implicitly, express or implied, by estoppel or otherwise, under any intellectual property rights. In the event that any of the abovementioned limitations or

exclusions does not apply, it is agreed that Azoteq’s total liability for all losses, damages and causes of action (in contract, tort (including without limitation, negligence) or otherwise) will not

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