LQ
NOT RECOMMENDED FOR NEW
DESIGNS
32-K
EY
QM
ATRIX
™ C
HARGE
-T
RANSFER
IC
Gnd
I4
AIN
Vcc
X4
X5
X2
X3
X1
I2
I3
QT60320C
Creates 32 ‘touch buttons’ through any dielectric
100% autocal for life - no adjustments required
'N' key rollover: senses all 32 keys in parallel
Keys individually adjustable for sensitivity
Mix 'n match key sizes & shapes in one panel
Tolerates a 20:1 variance in key sizes on a panel
Panel thicknesses to 5 cm or more
Back lit keys possible with ITO electrodes
LED status function drives
User-addressable multifunction drive pins
User-addressable internal eeprom
Simple, universal serial interface
5V single supply operation
44-pin TQFP package
One square inch (6.5 square cm) of PCB required
X6
X7
X8
RST
Vcc
Gnd
XT2
XT1
RX
TX
O1
1
2
3
4
5
6
7
8
9
44 43 42 41 40 39 38 37 36 35 34
33
32
31
30
I1
CC1
CC2
CS
Aref
AGnd
Vcc
O8
O7
O6
O5
QT60320
29
28
27
26
25
10
24
11
23
12 13 14 15 16 17 18 19 20 21 22
L1
O4
O3
O2
L2
Vcc
Y2
Y1
Gnd
Y4
Y3
APPLICATIONS -
Security keypanels
Industrial keyboards
Appliance controls
Outdoor keypads
ATM machines
Touch-screens
Automotive panels
Machine tools
The QT60320 digital charge-transfer (“QT”) QMatrix™ IC is designed to detect touch on up to 32 keys in a scanned X-Y matrix. It will
project the keys through almost any dielectric, like glass, plastic, stone, ceramic, and even most kinds of wood, up to thicknesses of
5 cm or more. The touch areas are defined as simple 2-part interdigitated electrodes of conductive material, like copper,
Indium-Tin-Oxide (ITO), or screened silver or carbon deposited on the rear of the control panel. Key sizes, shapes and placement are
almost entirely arbitrary; sizes and shapes of keys can be mixed within a single panel of keys and can vary by a factor of 20:1 or more
in area. The gain (sensitivity) and threshold of each key can be set individually via simple commands over the UART port, for example
via the freeware QmBtn program. Key setups are stored internally in an onboard eeprom and do not need to be reloaded.
The IC is designed specifically to work with appliances, ATM machines, security panels, portable instruments, machine tools, or
similar products that are subject to environmental 'challenges' or even physical attack. It permits the construction of 100% sealed,
watertight keypanels that are immune to environmental factors such as humidity and condensation, temperature, dirt accumulation, or
the physical deterioration of the panel surface from abrasion, chemicals, or abuse. To this end the QT60320 contains
Quantum-pioneered self-calibration, drift compensation, and digital filtering algorithms that make the sensing function extremely
robust and survivable.
The device can readily control keys over graphical LCD panels or LEDs when used with clear, conductive ITO electrodes. It does not
require 'chip on glass' or other exotic fabrication techniques, thus allowing the OEM to source the keymatrix from multiple vendors.
External circuitry consists of an opamp, a common PLD, and a quad fet switch, which can fit into a footprint of roughly 1 square inch
(6.5 sq. cm). The device also can control two status LEDs, and includes in addition 8 addressable output drive lines and 4 readable
spare input lines which can be used to control LEDs, LCDs, or other panel functions without requiring additional control lines from the
host CPU. It also makes available to the user 86 bytes of onboard writeable and readable eeprom via the serial interface, thus helping
to reduce system cost by eliminating extra components.
QT60320 technology makes use of an important new variant of charge-transfer sensing, transverse charge-transfer, in an XY format
that minimizes the number of required scan lines. Unlike older technologies it does not require one IC per key, and is cost competitive
even with some membrane technologies. In many cases it can also replace resistive XY sense elements commonly used in touch
screens, at a fraction of the price.
This part is not recommended for new designs. Consult Quantum for advice on alternatives.
AVAILABLE OPTIONS
T
A
TQFP
0
0
QT60320C-AS
-40 C to +105 C
LQ
Copyright © 1999, 2001 Quantum Research Group Ltd
QT60320C R1.08/01.03
QUANTUM [ QUANTUM RESEARCH GROUP ]
