Overview
The AT42QT1244 (QT1244) device is a digital burst mode charge-transfer (QT™) sensor, designed specifically for matrix layout touch controls. It includes all signal processing functions necessary to provide stable sensing under a wide variety of changing conditions. Only a few external parts are required for operation. The entire circuit can be built within a few square centimeters of single-sided PCB area. CEM-1 and FR1 punched, single-sided materials can be used for the lowest possible cost. The rear of the PCB can be mounted flush on the back of a glass or plastic panel using a conventional adhesive, such as 3M VHB two-sided adhesive acrylic film.

FEATUREs
● Number of keys:
   ● Up to 24
● Technology:
   ● Patented charge-transfer (transverse mode), with frequency hopping
● Key outline sizes:
   ● 6 mm × 6 mm or larger (panel thickness dependent); different sizes and shapes possible
● Key spacings:
   ● 8 mm or wider, center to center (panel thickness dependent)
● Electrode design:
   ● Two-part electrode shapes (drive-receive); wide variety of possible layouts
● Layers required:
   ● One layer (with jumpers), two layers (no jumpers)
● Electrode materials:
   ● PCB, FPCB, silver or carbon on film, ITO on film
● Panel materials:
   ● Plastic, glass, composites, painted surfaces (low particle density metallic paints possible)
● Panel thickness:
   ● Up to 50 mm glass, 20 mm plastic (key size dependent)
● Key sensitivity:
   ● Individually settable via simple commands over communication interface
● Interface:
   ● I2C slave mode (up to 400 kHz data transfer speed)
   ● Debug output
● Signal processing:
   ● Self-calibration, auto drift compensation, noise filtering, Adjacent Key Suppression® (AKS®) technology
● FMEA compliant design features
● IEC/EN/UL60730 compliant design features
   ● UL approval
   ● VDE compliance
   ● For use in both class B and class C safety-critical products
● Detects and Reports Key Failure
● Power:
   ● +3 V to 5 V
● Package:
   ● 32-pin 7 × 7 mm TQFP RoHS compliant
   ● 32-pin 5 × 5 mm QFN RoHS compliant