QT511-ISSG Datasheet, PDF (1/12 Pages) Quantum Research Group – QWHEEL TOUCH SLIDER IC

LQ
QT511-ISSG
QWHEEL™ TOUCH SLIDER IC
z Rotary finger-touch ‘wheel’ slider control
z Center-button compatible signal processing
z Extremely simple circuit - no external active components
z SPI slave-mode interface
z Self-calibration and drift compensation
z Spread-spectrum operation for optimal EMC compliance
z 2.5 - 5.5V single supply operation; very low power
z Enhanced power supply & thermal drift rejection
z 14-pin TSSOP Pb-free package
z Compatible with clear ITO over LCD construction
z Inexpensive, simple 1-sided PCB construction possible
z Reference design board available
VDD
SDO
/SS
SCLK
SNS3B
SNS3A
SNS2B
1
14
2
13
3 QT511 12
4
11
5
10
6
9
7
8
GND
DRDY
DETECT
SDI
SNS1A
SNS1B
SNS2A
APPLICATIONS
y Personal electronics
y Appliance controls
y Shaft encoders
y Automotive controls
The QT511 QSlide™ IC is a new type of rotary capacitive touch ‘slider’ sensor IC based on Quantum’s patented
charge-transfer methods. This unique IC allows designers to create speed or volume controls, menu bars, and other more
exotic forms of human interface on the panel of an appliance. Generally it can be used to replace any form of rotary knob,
through a completely sealed panel.
The device uses a simple, inexpensive resistive sensing element between three connection points. The sense element can be
circular or any polygon shape.
The QT511 can report a single rapid touch anywhere along the sense element, or, it can track a finger moving along the wheel
surface in real time. The device self-calibrates under command from a host controller.
This device uses three channels of simultaneous sensing across a resistive element to determine finger position, using
mathematical analysis. A positional accuracy of 5% (or better) is relatively easy to achieve. The acquisitions are performed in a
burst mode which uses proprietary spread-spectrum modulation for superior noise immunity and low emissions.
The output of the QT511 can also be used to create discrete controls in a circle, by interpreting sets of number ranges as
buttons. For example, the number range 0..19 can be button A, 30..49 button B, 60..79 button C etc. Continuous wheel action
and discrete controls can be mixed on a single element, or, the element can be reinterpreted differently at different times, for
example when used below or on top of an LCD to act as a menu input device that dynamically changes function in context. The
device is compatible with ITO (Indium Tin Oxide) overlays on top of various displays or simply to provide for a backlighting
effect.
The QT511 has two enhancements over the QT510. It is significantly more stable with temperature and other environmental
influences, and it recognizes a touch in the middle of the wheel as being invalid, which aids considerably in placing a touch
button in the center of the wheel. However, unlike the QT510 the QT511 does not have a proximity detection function.
LQ
Copyright © 2005 QRG Ltd
QT511-ISSG R6.01/1005