APPLICATIONS -

Automotive panels

Machine tools

ATM machines

Touch-screens

Appliance controls

Outdoor keypads

Security keypanels

Industrial keyboards

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.

LQ

Copyright © 1999, 2001 Quantum Research Group Ltd

QT60320C R1.08/01.03

QT60320C

NOT RECOMMENDED FOR NEW DESIGNS

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

O5

O6

O7

O8

Vcc

AGnd

Aref

CS

CC2

CC1

I1

1

2

3

4

5

6

7

8

9

10

11

23

24

25

26

27

28

29

30

31

32

33

44 43 42 41 40 39 38 37 36

34

35

12 13 14

22

21

19 20

18

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15

QT60320

QT60320C-AS

TQFP

AVAILABLE OPTIONS