QT11x VARIATIONS
QT111
QT112
QT115
Longer recalibration timeouts
Faster response time
Variable gain, daisy-chaining
4 August 2004
Copyright QRG Ltd. (UK)
Quantum Research Group Ltd.
4 August 2004
QT111-I / QT111H-I QProx™ 8-pin Sensor
See QT110 datasheet for primary information. This sheet only lists differences with the QT110.
This part is only available in -I suffix (-40..+85C)
Description
The QT111 is a touch sensor IC having recalibration timeouts (“max on-duration”) of 5 minutes and infinity. This
allows the device to be used in situations where recalibration timeouts are not desired, for example in certain
consumer, machine tool and process control applications where continuous touch over long periods is desired,
like hand-on-joystick sensors, dead-man switches, etc. Although the primary application of the device is still as a
‘touch sensor’, longer timeouts also aknowledge alternate uses for the QT110 family, for example in process
controls.
Differences with QT110
The QT111 sensor is exactly the same in all respects to the QT110 with the following exceptions shown in bold
(refer to Table 2-1 in the QT110 datasheet):
Table 2-1 Output Mode Strap Options
Tie
Pin 3 to:
DC Out
DC Out
Toggle
Pulse
Vdd
Vdd
Gnd
Gnd
Tie
Pin 4 to:
Vdd
Gnd
Gnd
Vdd
Max On-
Duration
300s
infinite
300s
300s
All other operating modes, specifications, and wiring should be read from the QT110 data sheet.
QT111H Version
The QT111H version is the same as the QT111 except has an active-high output.
Cautionary Notes
Care should be taken in infinite timeout mode that the Cs and Cx capacitances and the Vcc supply do
not drift substantially over the course of a detection; if any of these parameters change sufficiently
during the course of an active detection (remember: drift compensation is never performed during a
detection event) the sensor can either ‘stick on’ after the detected object is removed, or, the QT110’s
apparent sensitivity will be substantially reduced for a period of time until drift compensation can
recover the proper reference level. If possible, uses the lowest gain setting when using with long
timeouts.
If the sensor ‘sticks on’ after the detected object or substance is removed from the sense element, the
only way to clear the sensor may be to remove power momentarily in order to induce a full
recalibration.
Package Marking - QT111-I
DIP Package:
DIP devices are marked 'QT111'
SO8 Package:
Marked 'QT1 Y'
Package Marking - QT111H-I
DIP Package:
Not offered
SO8 Package:
Marked 'QT1 C'
QT111 QProx™ 8-pin Sensor
© 1999 QRG Ltd.
Quantum Research Group Ltd.
4 August 2004
QT112-I / QT112H-I QProx™ 8-pin Sensor
See QT110 datasheet for primary information. This sheet only lists differences with the QT110.
This part is only available in -I suffix (-40..+85C)
Description
The QT112 is a variant of the QT110 having a faster response time of 49ms worst case, and 25ms typical. It is
designed for those touch sensing applications where faster speed is paramount, for example in games and toys
where rapid reaction time is critical, or in machine tool controls where speed is important. It trades off power
consumption for speed. Also, note that the device has a consensus filter count 2 instead of 4, and does not have
an acoustic driver for a piezo 'beeper'.
Differences with the QT110
The QT112 sensor is exactly the same in all respects to the QT110 with the following exceptions (refer to Tables
4.3, 4.4, and 4.5 in the QT110 datasheet):
4.3 AC SPECIFICATIONS
Parameter
T
BS
T
R
Vdd = 3.0, Ta = recommended operating range
Min
Typ
24
49
Description
Burst spacing interval
Response time
Max
Units
ms
ms
Notes
4.4 SIGNAL PROCESSING
Description
Consensus filter length
Positive drift compensation rate
Negative drift compensation rate
Min
Typ
2
1,250
24
Max
Units
samples
ms/level
ms/level
Notes
4.5 DC SPECIFICATIONS
Vdd = 3.0V, Cs = 10nF, Cx = 5pF, Ta = recommended range, unless otherwise noted
Parameter
I
DD
Description
Supply current
Min
Typ
60
Max
Units
µA
Notes
The piezo acoustic driver has been removed, as the duration required to operate the
beeper would interfere with the sensing interval and slow down the device.
Piezo Driver Note:
QT112H Version
The QT112H version is the same as the QT112 except with an active-high output.
All other operating modes, specifications, and wiring should be taken from the QT110 data sheet.
Package Marking - QT112-I
DIP Package:
DIP devices are marked 'QT112'
SO8 Package:
Marked 'QT1 2I'
Package Marking - QT112H-I
DIP Package:
DIP devices are marked 'QT112H'
SO8 Package:
Marked 'QT1 M'
QT112 QProx™ 8-pin Sensor
© 1999 QRG Ltd.
Quantum Research Group Ltd.
4 August 2004
QT115-I / QT115H-I QProx™ 8-pin Sensor
See QT110 datasheet for primary information. This sheet only lists differences with the QT110.
This part is only available in -I suffix (-40..+85C)
Description
The QT115 is a variant of the QT110 having variable sensitivity and the ability to daisy-chain, allowing multiple
QT115's to be used in immediate proximity to each other to create a small touch panel of up to 10 keys. Like the
QT113, it has a variable threshold which can be modified by simply altering the value of the sample capacitor Cs,
which acts to modify gain. It does not include any of the option jumpers found on the QT110 or QT113; instead it
has a single option jumper for 'Master' or 'Slave' mode operation.
The QT115 includes 'Sync Out' and 'Sync In' pins for daisy-chaining. The first IC in the chain is the Master while
the remaining devices in the chain are slaves. Daisy-chaining lets each device take its turn in generating a burst,
free from interference by the other QT devices. In Master mode the IC operates autonomously, and generates a
20us negative Sync Out pulse on pin 3 after each burst. In Slave mode the IC issues a detection burst only after
it receives a negative Sync pulse on pin 4 from a prior device in the chain, which could be another Slave or a
Master. Slave devices in turn issue a 20us Sync pulse after each burst on pin 3.
The QT115 is designed for contact and prox sensing applications where high sensitivity is paramount, for
example when sensing through thick panels or windows or for security monitoring. The QT115 trades off power
consumption for speed and sensing range. Also, note that the device has a consensus filter count of 3 instead of
4, and does not have the drive capability for a piezo 'beeper'.
If desired, the Master device can be eliminated and the chain of Slave devices can be mastered from an external
pulse source of 20us negative pulses at the desired repetition rate. This potentially allows for faster operation.
Differences with the QT110
The QT115 IC is exactly the same in all respects to the QT110 with the following exceptions (refer to Tables 5.2,
5.3, 5.4, and 5.5 in the QT110 datasheet).
5.2 RECOMMENDED OPERATING CONDITIONS
Cx Load Capacitance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 to 100pF
Cs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10nF to 500nF
5.3 AC SPECIFICATIONS
Parameter
T
BS
1
T
BS
2
T
BL
T
R
VDD = 3.0, TA = RECOMMENDED OPERATING RANGE
Min
30
2
0.5
8
75
300
Description
Burst spacing interval, master
Burst spacing interval, slave
Burst length
Response time
Typ
40
Max
Units
ms
ms
ms
ms
Notes
Cs = 10nf to 500nf, Cx = 0
Cs = 10nf, Cx = 0
Cs = 10nf to 500nf, Cx = 0
Note 1
Note 1: Lengthens with increasing Cs but decreases with increasing Cx; see Chart 3.
5.4 SIGNAL PROCESSING
Description
Threshold differential, fixed
Hysteresis
Consensus filter length
Positive drift compensation rate
Negative drift compensation rate
Post-detection recalibration timer duration
Min
Typ
6
17
3
1,800
40
10
Max
Units
counts
%
samples
ms/level
ms/level
secs
Note 1
Notes
w.r.t. threshold cts.
Note 1: All percentage thresholds have been eliminated and replaced with a fixed threshold w.r.t. the reference level
QT113 QProx™ 8-pin Sensor
© 1999 QRG Ltd.
Quantum Research Group Ltd.
5.5 DC SPECIFICATIONS
Parameter
I
DD
I
DD
S
4 August 2004
Min
Typ
60
700
1,000
-
28
VDD = 3.0V, CS = 10NF, CX = 10PF, TA = RECOMMENDED RANGE
Max
Units
µA
µA
fF
Notes
Cs = 10nF to 100nF
Cs = 10nF to 100nF
Typical, see figs 1, 2; Note 1, 2
Description
Supply current, master mode
Supply current, slave mode
Sensitivity range
Note 1: All percentage thresholds have been eliminated and replaced with a fixed threshold w.r.t. reference level
Note 2: Sensitivity depends on value of Cx and Cs. Refer to Charts 1, 2.
Piezo Driver Note
The piezo acoustic driver has been removed, as the duration required to operate the beeper would interfere with
the sensing interval and slow down the device.
Sensitivity Adjustment Note
The device has a fixed threshold point of 6 counts of deviation. Gain pin adjustment (pin 5) has been eliminated
and replaced with a strap option for Master / Slave mode:
Table 1-1 Master/Slave Strap Options
Mode
Master
Slave
Tie Pin 5 to:
Vdd
Gnd
The sensitivity of the circuit is governed by the relative sizes of Cs and Cx. A detection is made if the signal rises
by 6 counts from the reference level; this amount, unlike the QT110, is not ratiometric to the signal level and
therefore the sensitivity can be altered by simply changing Cs. To provide a consistent level of sensitivity, only
stable types of capacitors are recommended for Cs, such as NPO, C0G, PPS film, and certain types of
polycarbonate when used over normal room temperature ranges.
Larger values of Cs will make the sensor more sensitive, while larger amounts of Cx will desensitize it (see
Charts 1, 2). Minimizing stray Cx is crucial if high levels of sensitivity are desired. By using values of Cs around
0.47uF (470nF), proximity distances of several centimeters can easily be obtained from small electrodes.
NOTE:
It is extremely important to maintain stable levels of Vdd, as the supply is used as a
reference. Minor fluctuations in Vdd WILL cause false triggers or rapid swings in gain. DO NOT use
bench power supplies or supply circuits shared with other digital functions. Ordinary 78L05 class
regulators are fine in almost all cases. The QT115 is an extremely sensitive device... do not take
power supply issues lightly.
Pin Functions
The QT115 pins are defined as shown:
Table 2-1 QT115 Pin Functions
PIN
1
2
3
4
5
6
7
8
Function
Vdd
Out
Sync Pulse Out (master or slave mode)
Sync Pulse In (slave mode only)
Master/Slave select
SNS1
SNS2
Gnd
Description
Power, +3V to +5V
Active-low output
20us nominal negative sync pulse
>10us, <50us negative pulse input to trigger in slave mode
In Master Mode: Connect to either Gnd or Vcc.
Vdd = Master mode, Gnd = Slave mode (strap option)
QT Sense pin 1
QT Sense pin 2
Ground, 0V
QT113 QProx™ 8-pin Sensor
© 1999 QRG Ltd.
