L
Q
QT511-ISSG
QW
HEEL
™ T
OUCH
S
LIDER
IC
Rotary finger-touch ‘wheel’ slider control
Center-button compatible signal processing
Extremely simple circuit - no external active components
SPI slave-mode interface
Self-calibration and drift compensation
Spread-spectrum operation for optimal EMC compliance
2.5 - 5.5V single supply operation; very low power
Enhanced power supply & thermal drift rejection
14-pin TSSOP Pb-free package
Compatible with clear ITO over LCD construction
Inexpensive, simple 1-sided PCB construction possible
Reference design board available
VDD
SDO
/SS
SCLK
SNS3B
SNS3A
SNS2B
1
2
3
4
5
6
7
14
13
GND
DRDY
DETECT
SDI
SNS1A
SNS1B
SNS2A
QT511
12
11
10
9
8
APPLICATIONS
Personal electronics
Appliance controls
Shaft encoders
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
QT [ QT OPTOELECTRONICS ]
