Atmel AT42QT1244 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: 2 I C 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 5V Package: 32-pin 7 7 mm TQFP RoHS compliant 32-pin 5 5 mm QFN RoHS compliant 9631EXAT4212/131. Pinout and Schematic 1.1 Pinout Configuration 32 31 30 29 28 27 26 25 M SYNC 1 24 Y1B CHANGE 2 23 Y0B VSS 3 22 A0 VDD 4 21 VSS QT1244 VSS 5 20 VDD VDD 6 19 A1 X6 7 18 VDD X7817 X5 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 M SYNC I Mains Sync input Vdd State change notification, active low. Has internal 2 CHANGE OD Leave open 20 k 50k pull-up resistor 3 VSS P Ground 4 VDD P Power 5 VSS P Ground 6 VDD P Power 7 X6 O X matrix drive line Leave open 8 X7 O X matrix drive line Leave open QT1244 PRELIMINARY DATASHEET 2 9631EXAT4212/13 DBG CLK Y2A VREF Y1A S SYNC/DBG DATA Y0A X0 RST X1 SCL X2 SDA X3 SMP X4 Y2B