Atmel AT42QT1245 24-key QMatrix FMEA IEC/EN/UL60730 Touch Sensor PRELIMINARY DATASHEET 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: SPI 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 5V Package: 32-pin 7 7 mm TQFP RoHS compliant 32-pin 5 5 mm QFN RoHS compliant 9632EXAT4212/131. Pinout and Schematic 1.1 Pinout Configuration 27 32 31 30 29 28 26 25 X3 1 24 Y1B X4 2 23 Y0B VSS 3 22 N/C VDD 4 21 VSS QT1245 VSS 5 20 VDD VDD 6 19 N/C X5 7 18 VDD X6817 SCK 9 10 11 12 13 14 15 16 1.2 Pin Descriptions Table 1-1. Pin Descriptions If Unused, connect Pin Name Type Comments To... 1 X3 O X matrix drive line Leave open 2 X4 O X matrix drive line Leave open 3 VSS P Ground 4 VDD P Power 5 VSS P Ground 6 VDD P Power 7 X5 O X matrix drive line Leave open 8 X6 O X matrix drive line Leave open QT1245 PRELIMINARY DATASHEET 2 9632EXAT4212/13 X7 X2 VREF X1 X0 SMP S SYNC CHANGE M SYNC RST Y2A DRDY Y1A SS MOSI Y0A MISO Y2B