QT  -  Series DataSheet
QT1081  -  8-KEY QTOUCH? SENSOR IC  -  Atmel  -  Touch Technology

This datasheet is applicable to all revision 1 chips
The QT1081 is an improved, lower cost, simplified circuit version of the popular QT1080 sensor IC. The QT1081 is designed for low cost appliance, mobile, and consumer electronics applications.
QTouch™ technology is a type of patented charge-transfer sensing method well known for its robust, stable, EMC-resistant characteristics.
It is the only all-digital capacitive sensing technology in the market today. This technology has over a decade of applications experience spanning thousands of designs.
QTouch circuits are renowned for simplicity, reliability, ease of design, and cost effectiveness.
QTouch™ sensors employ a single reference capacitor tied to two pins of the chip for each sensing key; a signal trace leads from one of the pins to the sensing electrode which forms the key. The sensing electrode can be a simple solid shape such as a rectangle or circle. An LED can be placed near or inside the solid circle for illumination.
The key electrodes can be designed into a conventional printed circuit board (PCB) or flexible printed circuit board (FPCB) as a copper pattern, or as printed conductive ink.
The QT1081 is also compatible with clear films to make simple button-style touch screens over LCD displays.
AT A GLANCE
Number of keys: 1 to 8
Technology: Patented spread-spectrum charge-transfer (one-per-key mode)
Key outline sizes: 5mm x 5mm or larger (panel thickness dependent); widely different sizes and shapes possible
Key spacings: 6mm or wider, center to center (panel thickness, human factors dependent)
Electrode design: Single solid or ring shaped electrodes; wide variety of possible layouts
Layers required: One layer substrate; electrodes and components can be on same side
Substrates: FR-4, low cost CEM-1 or FR-2 PCB materials; polyamide FPCB; PET films, glass
Electrode materials: Copper, silver, carbon, ITO, Orgacon† ink (virtually anything electrically conductive)
Panel materials: Plastic, glass, composites, painted surfaces (low particle density metallic paints possible)
Adjacent Metal: Compatible with grounded metal immediately next to keys
Panel thickness: Up to 50mm glass, 20mm plastic (key size dependent)
Key sensitivity: Settable via change in reference capacitor (Cs) value
Outputs: Parallel discrete output, one-per-key, active-high
Moisture tolerance: Good
Power: 2.8V ~ 5.0V, <15μA (8 keys at 2.8V, 340ms Low Power mode).
Package: 32-pin 5 x 5mm QFN RoHS compliant
Signal processing: Self-calibration, auto drift compensation, noise filtering, patented Adjacent Key SuppressionTM
Applications: Portable devices, domestic appliances and A/V gear, PC peripherals, office equipment
Patents: AKS™ (patented Adjacent Key Suppression)
QTouch™ (patented Charge-transfer method)