Electronic Components Datasheet Search
  English  ▼

Delete All
ON OFF
ALLDATASHEET.NET

X  

Preview PDF Download HTML

QT110-DG Datasheet(PDF) 2 Page - Quantum Research Group

Part No. QT110-DG
Description  QTOUCH??SENSOR IC
Download  12 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Manufacturer  QUANTUM [Quantum Research Group]
Direct Link  http://www.qprox.com
Logo QUANTUM - Quantum Research Group

QT110-DG Datasheet(HTML) 2 Page - Quantum Research Group

  QT110-DG Datasheet HTML 1Page - Quantum Research Group QT110-DG Datasheet HTML 2Page - Quantum Research Group QT110-DG Datasheet HTML 3Page - Quantum Research Group QT110-DG Datasheet HTML 4Page - Quantum Research Group QT110-DG Datasheet HTML 5Page - Quantum Research Group QT110-DG Datasheet HTML 6Page - Quantum Research Group QT110-DG Datasheet HTML 7Page - Quantum Research Group QT110-DG Datasheet HTML 8Page - Quantum Research Group QT110-DG Datasheet HTML 9Page - Quantum Research Group Next Button
Zoom Inzoom in Zoom Outzoom out
 2 / 12 page
background image
1 - OVERVIEW
The QT110 is a digital burst mode charge-transfer (QT) sensor
designed specifically for touch controls; it includes all hardware
and signal processing functions necessary to provide stable
sensing under a wide variety of changing conditions. Only a
few low cost, non-critical discrete external parts are required for
operation.
Figure 1-1 shows the basic QT110 circuit using the device,
with a conventional output drive and power supply
connections. Figure 1-2 shows a second configuration using a
common power/signal rail which can be a long twisted pair from
a controller; this configuration uses the built-in pulse mode to
transmit output state to the host controller (QT110 only).
1.1 BASIC OPERATION
The QT110 employs low duty cycle bursts of charge-transfer
cycles to acquire its signal. Burst mode permits power
consumption in the low microamp range, dramatically reduces
EMC problems, and yet permits excellent response time.
Internally the signals are digitally processed to reject impulse
noise, using a 'consensus' filter which requires four
consecutive confirmations of a detection before the output is
activated.
The QT switches and charge measurement hardware functions
are all internal to the QT110 (Figure 1-3). A single-slope
switched capacitor ADC includes both the required QT charge
and transfer switches in a configuration that provides direct
ADC conversion. Vdd is used as the charge reference voltage.
Larger values of Cx cause the charge transferred into Cs to
rise more rapidly, reducing available resolution; as a minimum
resolution is required for proper operation, this can result in
dramatically reduced apparent gain.
The IC is highly tolerant of changes in Cs since it computes the
signal threshold level ratiometrically. Cs is thus non-critical and
can be an X7R type. As Cs changes with temperature, the
internal drift compensation mechanism also adjusts for the drift
automatically.
Piezo sounder drive: The QT110 can drive a piezo sounder
after a detection for feedback. The piezo sounder replaces or
augments the Cs capacitor; this works since piezo sounders
are also capacitors, albeit with a large thermal drift coefficient.
If Cpiezo is in the proper range, no additional capacitor is
required. If Cpiezo is too small, it can simply be ‘topped up’ with a
ceramic capacitor in parallel. The QT110 drives a ~4kHz signal
across SNS1 and SNS2 to make the piezo (if installed) sound a
short tone for 75ms immediately after detection, to act as an
audible confirmation.
Option pins allow the selection or alteration of several other
special features and sensitivity.
1.2 ELECTRODE DRIVE
The internal ADC treats Cs as a floating transfer capacitor; as a
direct result, the sense electrode can in theory be connected to
either SNS1 or SNS2 with no performance difference.
However, the noise immunity of the device is improved by
connecting the electrode to SNS2, preferably via a series
resistor Re (Figure 1-1) to roll off higher harmonic frequencies,
both outbound and inbound.
In order to reduce power consumption and to assist in
discharging Cs between acquisition bursts, a 470K series
resistor Rs should be connected across Cs (Figure 1-1).
The rule Cs >> Cx must be observed for proper operation.
Normally Cx is on the order of 10pF or so, while Cs might be
10nF (10,000pF), or a ratio of about 1:1000.
It is important to minimize the amount of unnecessary stray
capacitance Cx, for example by minimizing trace lengths and
widths and backing off adjacent ground traces and planes so
as keep gain high for a given value of Cs, and to allow for a
larger sensing electrode size if so desired.
The PCB traces, wiring, and any components associated with
or in contact with SNS1 and SNS2 will become touch sensitive
and should be treated with caution to limit the touch area to the
desired location.
1.3 ELECTRODE DESIGN
1.3.1 ELECTRODE GEOMETRY AND SIZE
There is no restriction on the shape of the electrode; in most
cases common sense and a little experimentation can result in
a good electrode design. The QT110 will operate equally well
with long, thin electrodes as with round or square ones; even
random shapes are acceptable. The electrode can also be a
3-dimensional surface or object. Sensitivity is related to
electrode surface area, orientation with respect to the object
being sensed, object composition, and
the ground coupling quality of both the
sensor circuit and the sensed object.
1.3.2 KIRCHOFFS CURRENT LAW
Like all capacitance sensors, the QT110
relies on Kirchoff’s Current Law (Figure
1-5) to detect the change in capacitance
of the electrode. This law as applied to
capacitive sensing requires that the
sensor’s field current must complete a
loop, returning back to its source in
order for capacitance to be sensed.
Although most designers relate to
Kirchoff’s law with regard to hardwired
circuits, it applies equally to capacitive
LQ
2
QT110 R1.04/0405
Figure 1-1 Standard mode options
SENSING
ELECTRODE
Cs
Rs
2nF - 500nF
3
46
5
1
+2.5 ~ +5
7
2
OUT
OPT1
OPT2
GAIN
SNS1
SNS2
Vss
Vdd
OUTPUT = DC
TIMEOUT = 10 Secs
TOGGLE = OFF
GAIN = HIGH
Cx
8
RE
Figure 1-2 2-wire operation, self-powered
+
10µF
1N4148
n-ch Mosfet
CMOS
LOGIC
3.5 - 5.5V
1K
Twisted
pair
Cs
8
OUT
OPT1
OPT2
GAIN
SNS1
SNS2
Vss
Vdd
3
46
5
1
7
2
Rs
SENSING
ELECTRODE
Cx
RE


Similar Part No. - QT110-DG

ManufacturerPart No.DatasheetDescription
Quantum Research Group
Quantum Research Group
QT110 QUANTUM-QT110 Datasheet
385Kb / 12P
   SENSOR ICs
QT1100A QUANTUM-QT1100A Datasheet
561Kb / 42P
   10 KEY QTOUCH SENSOR IC
QT1100A-ISG QUANTUM-QT1100A-ISG Datasheet
561Kb / 42P
   10 KEY QTOUCH SENSOR IC
QT1101 QUANTUM-QT1101 Datasheet
234Kb / 16P
   10 KEY QTOUCH SENSOR IC
QT1101-IS48G QUANTUM-QT1101-IS48G Datasheet
234Kb / 16P
   10 KEY QTOUCH SENSOR IC
More results

Similar Description - QT110-DG

ManufacturerPart No.DatasheetDescription
ATMEL Corporation
ATMEL Corporation
AT42QT2100-AU ATMEL-AT42QT2100-AU Datasheet
478Kb / 44P
   QTouch Touch Sensor IC
AT42QT2100 ATMEL-AT42QT2100_14 Datasheet
478Kb / 44P
   QTouch Touch Sensor IC
AT42QT2100 ATMEL-AT42QT2100 Datasheet
478Kb / 44P
   QTouch Touch Sensor IC
Quantum Research Group
Quantum Research Group
QT240-ISSG QUANTUM-QT240-ISSG Datasheet
277Kb / 12P
   4 KEY QTOUCH SENSOR IC
QT240 QUANTUM-QT240 Datasheet
258Kb / 12P
   4 KEY QTOUCH SENSOR IC
QT220 QUANTUM-QT220 Datasheet
326Kb / 12P
   2 KEY QTOUCH SENSOR IC
QT1100A QUANTUM-QT1100A Datasheet
561Kb / 42P
   10 KEY QTOUCH SENSOR IC
QT1101 QUANTUM-QT1101 Datasheet
234Kb / 16P
   10 KEY QTOUCH SENSOR IC
QT1080 QUANTUM-QT1080 Datasheet
205Kb / 16P
   8 KEY QTOUCH SENSOR IC
QT1081 QUANTUM-QT1081 Datasheet
246Kb / 20P
   8-KEY QTOUCH SENSOR IC
More results


Html Pages

1  2  3  4  5  6  7  8  9  10  11  12 


Datasheet Download

Go To PDF Page


Link URL




Privacy Policy
ALLDATASHEET.NET
Does ALLDATASHEET help your business so far?  [ DONATE ] 

About Alldatasheet   |   Advertisement   |   Contact us   |   Privacy Policy   |   Link Exchange   |   Manufacturer List
All Rights Reserved©Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com
Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn
Indian : Alldatasheet.in  |   Mexican : Alldatasheet.com.mx  |   British : Alldatasheet.co.uk  |   New Zealand : Alldatasheet.co.nz