DESCRIPTION
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.

FEATURES
*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

APPLICATIONS
*Automotive panels
*Machine tools
*ATM machines
*Touch-screens
*Appliance controls
*Outdoor keypads
*Security keypanels
*Industrial keyboards

QT60320C-AS, QT60320C-A

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