Quantum QT1106 DATA SHEET

lQ

QT1106

QW

HEEL

™/QS

LIDE

™/QT

OUCH

™ IC

This datasheet is applicable to all revision 8I chips

QT1106 charge-transfer (‘QT’) QTouchTM IC is a self-contained, patented
charge-transfer capacitive controller capable of detecting near-proximity

2423222120

19 18

17

or touch on up to seven electrodes and a wheel/slider. It allows
electrodes to project sense fields through any dielectric such as glass or
plastic. These electrodes are laid out as a scroller (e.g. a wheel or slider)
plus seven additional independent keys. Each key channel can be tuned
for a unique sensitivity level by simply changing a corresponding external
Cs capacitor, whereas the wheel/slider’s sensitivity can be changed
dynamically through SPI commands.

The wheel/slider uses a simple, inexpensive sensing element between
three connection points. The QT1106 can report a single rapid touch

MOSI

MISO
SNSA
SNSA
SNSA

SNSA1
SNSA2
SNSA3

25
26
27
28
29
30

31

32

QT1106
32-QFN

SNSB2

16

SNSB3

15
14

SNSB

13

SNSB

12

SNSB

11

SNSB

10

SNSB5

9

anywhere along the sense elements, or it can track a finger moving along
the wheel/slider’s surface in real time.

By using the charge-transfer principle, this device delivers a level of
performance clearly superior to older technologies yet
is highly cost-effective. Spread-spectrum burst technology provides

1

2345678

VDD

OSC

/RST

SPREAD

E
G
N
A
H
C

AT A GLANCE

Number of keys: 0 to 7, one slider or one wheel
Technology: Patented spread-spectrum charge-transfer
Key outline sizes: 5mm x 5mm or larger (panel thickness dependen t); w i de ly di fferent si ze s and sha pes po ssib le
Key spacings: 6mm or wider, center to center (panel thickness, human factors dependent)
Key design: Single solid or ring shaped electrodes; wide variety of possible layouts
Wheel size: Typically 30mm- 50mm diameter, resistored wheel up to 80mm diameter, typical width 12mm
Slider size: Typically 50mm-100mm length, typical width 12mm
Wheel electrode design: Resistorless/resistored design
Slider electrode design: Resistorless/resistored design (can be an arc or other irregular shape)
Layers required: One layer substrate; electrodes and components can be on same side
Substrates: FR-4, low cost CEM-1 or FR-2 PCB materials; polyamide FPCB; PET films, glass

†

Electrode materials: Copper, silver, carbon, ITO, Orgacon
Panel materials: Plastic, glass, composites, painted surfaces (nonconductive paints)
Adjacent Metal: Compatible with grounded metal immediately next to keys
Key panel thickness: Up to 15mm glass, 10mm plastic (key size dependent)
Wheel/Slider panel thickness: Up to 4mm glass, 3mm plastic
Key sensitivity: Adjustable via change in sampling capacitor (Cs) value
Outputs: SPI
Moisture tolerance: Good
Power: 2.8V ~ 5.0V
Package: 32-pin 5 x 5mm QFN RoHS compliant
Signal processing: Self-calibration, auto drift comp ensa ti on, no ise filte ring , pate nted Adjacent Key Suppressi on
Applications: Portable devices, domestic appliances and A/V gear, PC peripherals, office equipment
Patents: AKS™ (patented Adjacent Key Suppression)

QTouch™ (patented Charge-transfer method)
QWheel™/QSlide™ (patented Charge-transfer method) (patent-pending QWheel/QSlide

sensing configuration)

†

Orgacon is a registered trademark of Agfa-Gevaert N.V

AVAILABLE OPTIONS

A

LQC

ink (virtually anything electrically conductive)

TM

32-QFNT

QT1106-ISG-400C to +850C

Copyright © 2006-2007 QRG Ltd

QT1106_8IR0.06_0407

Contents

1 Overview

1.1 Introduction

1.2 Burst Operation

1.3 User Interface Layout Options

1.4 Slider and Wheel Construction

1.5 QMagicTM Proximity Effect

1.6 SPI Interface

1.7 Basic Power Modes

2 Signal Processing

2.1 Power-up Self-calibration

2.2 Drift Compensation

2.3 Detection Integrator Filter

2.4 AKSTM Adjacent Key Suppression

2.5 Autorecalibration (MOD)

2.6 QMagicTM Proximity Sensor

2.7 Faulty and Unused Keys

2.8 Wiring

3 SPI Interface

3.1 Introduction

3.2 CHANGE Pin

3.3 SPI Parameters

3.4 SPI Operation

3.5 SPI Host Commands

3.6 SPI Responses

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1.7.1 Overview

1.7.2 Free Run Mode

1.7.3 LP Mode

1.7.4 Sleep Mode

1.7.5 Sync Mode

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3.5.1 Overview

3.5.2 Normal Command Mode

3.5.3 Custom Threshold Command Mode

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4 Operating Modes

3

4.1 Introduction

3

4.2 Free Run Mode

3

4.3 LP Mode

3

4.4 Sleep Mode

3

4.5 Sync Mode

3

5 Reset

3

5.1 Introduction

4

5.2 Delay to SPI Functionality

4

5.3 Reset Delay to Touch Detection

4

5.4 Mode Setting After Reset

4

6 Design Notes

4

6.1 Oscillator Frequency

4

6.2 Spread-spectrum Circuit

4

6.3 Cs Sample Capacitors - Sensitivity

4

6.4 Rsns Resistors

4

6.5 Thermal Stability

4

6.6 Power Supply

4

6.7 PCB Layout and Construction

4

7 Specifications

5

7.1 Absolute Maximum Specifications

5

7.2 Recommended Operating Conditions

6

7.3 AC Specifications

8

7.4 DC Specifications

8

7.5 Signal Processing

8

7.6 Idd Curves

8

7.7 Mechanical Dimensions - 32-QFN Package

8

7.8 Part Marking

9

7.9 Moisture Sensitivity Level (MSL)

9

8 Datasheet Control

9
10
10

8.1 Changes

8.2 Numbering Convention

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LQ

2 QT1106_8IR0.06_0407

1 Overview

1.1 Introduction

The QT1106 is an easy to use sensor IC based on
Quantum’s patented charge-transfer (‘QT’) principles for
robust operation and ease of design. This device has many
advanced features which provide for reliable, trouble-free
operation over the life of the product. In particular the
QT1106 features advanced self-calibration, drift
compensation, and fast thermal tracking. Unlike prior
devices, the QT1106 can tolerate power supply fluctuations
better in order to eliminate the need for a voltage regulator in
many cases.

1.2 Burst Operation

The device operates in burst mode. Each key is acquired
using a burst of charge-transfer sensing pulses whose count
varies depending on the value of the sense capacitor Cs and
the load capacitance Cx (finger touch capacitance and circuit
stray capacitance).

The channels’ signals are acquired using three successive
bursts of pulses:

Burst 1: B1, B3, B5, B7 (for discrete keys 1, 3, 5, 7)
Burst 2: B2, B4, B6 (for discrete keys 2, 4, 6)
Burst 3: A1, A2, A3 (for wheel or slider)

Bursts always operate in 1, 2, 3 sequence as a group and
occur one right after the other with minimum delay. The
groups are separated by an interval of time that can be used
for SPI communications.

Spread-spectrum operation - Bursts can operate over a
spread of frequencies, so that external fields will have
minimal effect on key operation and emissions are very
weak.

Spread-spectrum operation works together with the ‘detect
integrator’ (DI) mechanism to dramatically reduce the
probability of false detection due to noise. An external RC
circuit is required to implement spread spectrum, but this
circuit is optional.

1.3 User Interface Layout Options

The QT1106 can sense through all common plastics or glass
or other dielectric materials up to 10mm thick. It can be used
to implement a linear slider or rotary scroll wheel plus seven
additional discrete keys. The slider or wheel indicates
absolute positions.

1.4 Slider and Wheel Construction

The QT1106 can connect to either a wheel or a linear slider
element (Figure 1.1). Selection of wheel or linear operation is
set through an SPI command. The basis of these designs is
found in US Patent 4,264,903 (expired).

The first and last positions of the linear slider have larger
touch areas.

As with touch button electrodes, wheels and sliders can be
constructed as etched areas on a PCB or flex circuit, or from
clear conductors such as Indium Tin Oxide (ITO) or screen­printed Orgacon™ (Agfa) to allow backlighting effects, or for
use over an LCD display.

1.5 QMagicTM Proximity Effect

Channel 7 of the QT1106 can optionally operate a ‘magic on’
function based on hand or body proximity to a product. By
using a relatively large electrode inside the product’s
enclosure and a larger value of Csb7 (see Figure 2.1), the
product can auto power up or activate its display with hand
approach. This simple feature can add enormous sales
appeal to almost any product.

1.6 SPI Interface

The QT1106 uses a five-wire SPI interface. In addition to the
standard four SPI signals (/SS, SCLK, MOSI and MISO),
there is a DRDY (data ready) output for flow control.

The QT1106 also provides a CHANGE signal to indicate
when there has been a change in detection state. This
removes the need for the host to poll the QT1106
continuously.

On each SPI transfer the host sends three bytes to the
QT1106 and the QT1106 simultaneously sends three bytes
to the host. The bytes sent from the host provide the QT1106
with all its configuration information; the bytes sent from the
QT1106 convey the key states.

(downloadable example CAD files for wheels and sliders can be found on the Quantum

SNSA3

0

SNSA1

Position (at 7 bits - 0 to 127)

Lq

Figure 1.1 All-Metal Slider and Wheel Construction

website,http://www.qprox.com/toolbox, then click QT1106)

Tips of triangles should be
spaced <=4mm apart.

<=4mm

Position 85

SNSA2

1 to 126

SNSA2

SNSA3

127

3 QT1106_8IR0.06_0407

Position 0

SNSA3

<=4mm

Position 43

SNSA1

1.7 Basic Power Modes

1.7.1 Overview

The device features a number of modes to set the current
drain and speed of response.

The available operating modes are:

• Free Run - fastest detection response at all times

• LP mode - low power, slower touch sensing response

• Sleep - microamp-level current drain

• Sync mode - for noise suppression of low frequencies

1.7.2 Free Run Mode

This mode uses a continuous stream of acquire bursts. Free
Run mode has, in consequence, the highest power drain of
all the QT1106 operating modes but the fastest response
time.

1.7.3 LP Mode

In LP (low power) mode, the QT1106 spends most of the
time sleeping to conserve power; it wakes itself periodically to
perform acquire bursts, then normally goes back to sleep
again.

The QT1106 provides a choice of intervals between acquire
bursts to allow an appropriate speed/power trade-off to be
made for each product.

1.7.4 Sleep Mode

In Sleep mode, the QT1106 shuts down to conserve power; it
will remain in this mode forever or until the host wakes it
using the /SS pin.

1.7.5 Sync Mode

In this mode the device will synchronize to the host in a way
that allows for the suppression of heavy low frequency noise;
for example, from mains frequencies and their harmonics.

2 Signal Processing

2.1 Power-up Self-calibration

On power-up or after reset, all 10 channels are typically
calibrated and operational within 650ms.

2.2 Drift Compensation

This operates to correct the reference level of each key
automatically over time; it suppresses false detections
caused by changes in temperature, humidity, dirt and other
environmental effects.

2.3 Detection Integrator Filter

Detect Integrator (DI) filter confirmation reduces the effects of
noise on key states. The DI mechanism requires a specified
number of measurements that qualify as detections (and
these must occur in a row) or the detection will not be
reported.

In a similar manner, the end of a touch (loss of signal) also
has to be confirmed over several measurements. The
QT1106 provides a choice of either two or six DI
measurements for confirming start of touch; end of touch
always uses two measurements.

The DI mechanism works together with spread spectrum
operation to dramatically reduce the effects of noise.

2.4 AKSTM Adjacent Key Suppression

This patented feature works to prevent multiple keys from
responding to a single touch. This can happen with closely
spaced keys, or a scroll wheel that has buttons very near it.

AKS operates by comparing signal strengths from keys within
a group of keys to suppress touch detections from those that
have a weaker signal change than the dominant one.

When enabled globally on the QT1106, AKS allows only one
independent key, or the scroll section, to indicate a touch at a
time. Additionally, the QT1106 has options for partial AKS;
where some keys are included in the AKS operation and
others are not affected. In this case only one key in the AKS
group can indicate a touch at any time; other keys can
indicate touch in any combination.

AKS can also be disabled.

2.5 Autorecalibration (MOD)

The device can time out and recalibrate each key
independently after a continuous touch detection that lasts for
the chosen ‘Maximum on-duration’ (MOD). This ensures that
a key can never become ‘stuck on’ due to foreign objects or
other external influences.

After recalibration the key will continue to function normally.
The nominal delay is selectable to be either 10s, 20s, 60s, or
infinite (disabled), though the actual delay is different in some
operating modes (see Table 2.1).

Table 2.1 Maximum On-duration

Max on-durationsOperating Mode

10s, 20s, 60sFree Run

LP mode,
200ms1 response (120ms2)

LP mode,

1

280ms
LP mode,

440ms1 response (360ms2)
LP mode,

760ms
(typ 55Hz sync)

1

response times are estimated using a DI of six counts.

2

response times are estimated using a DI of two counts.

Note: all response times are based on typical sense
capacitor values.

The device also autorecalibrates all keys when one or more
normal keys’ signal reflect a sufficient decrease in
capacitance from the reference level (signal error). If QMagic
Proximity mode is active, a signal error on the Proximity Key
(Key 7) will only recalibrate itself. This is filtered in a manner
similar to the DI filter; the decrease in capacitance must be
seen for at least six successive cycles. Hence, in Free Run
mode the device typically recalibrates within 400ms so as to
recover normal operation quickly.

response (200ms2)

1

response (680ms2)

10s, 20s, 60s
10s, 20s, 60s
15s, 30s, 88s

28s, 55s, 164s

10s, 20s, 60sSync mode

(vary with sync rate)

n/aSleep mode

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4 QT1106_8IR0.06_0407

2.6 QMagicTM Proximity Sensor

Key 7 (SNSB7) can be optimized for operation as a hand
proximity sensor via the serial interface (see Section 3.5.2,
Prox = 1). The proximity sensitivity of channel 7 can be
increased by a higher value of Cs. The AKS mode should be
set to mode 101, to ensure that the proximity key does not
lock out other keys or the wheel/slider.

Note that proximity fields are often unstable especially in
products that can move around, such as mobile phones and
MP3 players. In particular, the proximity channel can stick on
after a detection. As soon as possible after proximity
channel 7 becomes active, it should be recalibrated via the
serial interface (see Section 3.5.2, CalK = 1, Cal Key Num
bits = 111) in order to clear the proximity channel.

Design of proximity electrodes requires care, so as to ensure
that the electrode area is maximized whilst ensuring
adequate and easy coupling to a hand as it approaches the
equipment.

2.7 Faulty and Unused Keys

Any sense channel that does not have its sense capacitor
(Cs) fitted is assumed to be either faulty or unused. This
channel takes no further part in operation unless a
host-commanded recalibration operation shows it to have an
in-range burst count again.

This is important for sense channels that have an open or
short circuit fault across
cause very long acquire bursts, and in consequence would
slow the operation of the entire QT1106.

Cs. Such channels would otherwise

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5 QT1106_8IR0.06_0407

2.8 Wiring

Table 2.2 Pinlist

32-QFN

Pin

Oscillator current driveIOSC4

16

Pin Type

I/O CMOS input/output
I CMOS input only
OD CMOS open drain output (pull up to Vdd)
OF CMOS output that can float during Reset, Sleep or LP modes
P Ground or power

Resistor to Vdd and optional

spread-spectrum RC network

If UnusedNotesFunctionTypeName

Open-Spread-spectrum driveODSPREAD1

VddActive low resetReset inputI/RST2

-+2.8 to +5.0VPowerPVdd3

-

-Leave open--n/c5

-To hostState change notificationOFCHANGE6
OpenSense pinTo Csb7I/OSNSB77
OpenSense pinTo Csb6I/OSNSB68
OpenSense pinTo Csb5I/OSNSB59
OpenSense pinTo any Csb + KeyI/OSNSB10
OpenSense pinTo any Csb + KeyI/OSNSB11
OpenSense pinTo any Csb + KeyI/OSNSB12
OpenSense pinTo any Csb + KeyI/OSNSB13
OpenSense pinTo Csb4I/OSNSB414
OpenSense pinTo Csb3I/OSNSB315
OpenSense pinTo Csb2I/OSNSB2
OpenSense pinTo Csb1I/OSNSB117
OpenSense pinTo any Csb + KeyI/OSNSB18
OpenSense pinTo any Csb + KeyI/OSNSB19
OpenSense pinTo any Csb + KeyI/OSNSB20

-SPI handshake lineSPI Data ReadyOFDRDY21

--GroundPVss22

-SPI serial bit clockSPI ClockISCLK23

-Idle high, slave select lineSPI Slave Select inI/SS24

-Data from host to QT1106SPI Master Out /Slave InIMOSI25

-Data from QT1106 to hostSPI Master In / Serial OutOFMISO26
OpenSense pinTo any Csa + wheel/sliderI/OSNSA27
OpenSense pinTo any Csa + wheel/sliderI/OSNSA28
OpenSense pinTo any Csa + wheel/sliderI/OSNSA29
OpenSense pin position 43To Csa1I/OSNSA130
OpenSense pin position 85To Csa2I/OSNSA231
OpenSense pin position 0To Csa3I/OSNSA332

Note: Sense terminals can be twinned with any sense drive terminals of the same group, e.g. SNSA1 can be
paired with any SNSA terminal.

Suggested regulator manufacturers:

• Toko (XC6215 series)

• Seiko (S817 series)

• BCDSemi (AP2121 series)

Re Figure 2.1 check the following sections for the variable component values:

• Section 6.3, page 13: Cs capacitors (Csb)

• Section 6.4, page 14: Sample resistors (R

SNS

)

• Section 6.6, page 14: Voltage levels

• Page 7: Css capacitor

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6 QT1106_8IR0.06_0407

Vunreg

KEY 3

KEY 2

KEY 1

The wheel shows positions at
7-bit resolution. See the table
at the end of Section 3.5.2 for
other resolutions.

CHANGE out

Sense terminals can be twinned with any

NOTE:

e.g. SNSA1 can be paired with any SNSA terminal.
SNSA pins: 27 ,28, 29

SNSB pins: 10, 11, 12, 13, 18, 19, 20

127 0

Figure 2.1 Connection Diagram (32-QFN Package)

VDD

Note: One bypass capacitor to be
tightly wired between Vdd and Vss.
Follow recommendations from regulator
manufacturer for input and output
capacitors.

2

/RST

SNSB

SNSB7

SNSB

SNSB6

SNSB

SNSB5

QT1106

4.7uF

Voltage Reg

Keep these parts

close to the IC

R

SNSB4

R

SNSB3

R

SNSB2

R

SNSB1

4.7uF 100nF

14

C

Sb4

C

Sb3

C

Sb2

C

Sb1

SNSB4

13

SNSB

15

SNSB3
SNSB

16

SNSB2

19

SNSB

17

SNSB1

18

SNSB

3

VDD

32-QFN

32

R

SNSA3

R

4385

SNSA1

R

SNSA2

100K

C

Sa3

C

Sa1

C

Sa2

27

30

29

31

28

6

SNSA3
SNSA

SNSA1

SNSA

SNSA2
SNSA

CHANGE

VSS

22

N.C.

OSC

SPREAD

DRDY

SCLK
MISO
MOSI

/SS

12

C

7

11

C

8

10

C

9

5
4

1

21

23

26

25
24

Keep these parts

close to the IC

Sb7

Sb6

Sb5

VDD

**Rb1

**

See the table below for
suggested resistor and capacitor
values, with and without spread
spectrum.

**Rb2

No Spread-spectrum:
Replace Css with 100k resistor and remove Rb2

*

Css

R

R

R

100k

SNSB7

KEY 7

SNSB6

KEY 6

SNSB5

KEY 5

SPI DRDY out
SPI SCLK in
SPI MISO out
SPI MOSI in

SPI /SS in

IMPORTANT DESIGN GUIDELINES:

• The sensitivities of the various sense channels are determined by the values of the respective Cs

capacitors (i.e. Csb1,
Csb7, etc.); these values will require adjustment based on building a prototype product and testing the sensitivity
experimentally.

• Rb1, Rb2 sets the oscillator frequency; recommended values are:

Without Spread SpectrumWith Spread SpectrumVdd Range

CssRb2Rb1CssRb2Rb1

27k12k< 3 V

see note

below

15k
18k22k12k3.0~3.6V
20k27k15k> 3.6V

not fitted

replace with

100k resistor

• The required value of the spread-spectrum capacitor (Css) will vary according to the lengths of the acquire bursts. A
typical value is 100nF-220nF.

• When the QT1106 is running the OSC pin has a DC voltage typically between 1V and 1.5V; the use of spread
spectrum will cause a small low-frequency variation in the voltage. The internal oscillator signal is not visible on this
pin.

• Signals DRDY and CHANGE may need pull-down resistors, see Section 5 on page 13.

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7 QT1106_8IR0.06_0407