Touch Sensor Capacitive 16 Key 1.8V to 5.5V Surface Mount 28-Pin MLF EP

The AT42QT2161-MMU is a digital burst mode charge-transfer (QT) sensor designed specifically for matrix layout touch controls. It can use up to 16 keys and a slider (constructed from 2-8 keys). There are three dedicated General Purpose Input/Outputs (GPIOs) which can be used as inputs for mechanical switches etc. or as driven outputs. There are eight shared General Purpose Outputs (GPOs) (XO - X7) which are driven outputs only. There is PWM control for all GPIO/GPOs. The QT2161 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 PCB’s rear 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. The device uses an l²C-compatible interface to allow key data to be extracted and to permit individual key parameter setup. The command structure is designed to minimize the amount of data traffic while maximizing the amount of information conveyed.

• Number of keys: up to 16 keys, and one slider (constructed from 2 to 8 keys)
• Number of I/O lines: 11 (3 dedicated - configurable for input or output, 8 shared -output only), PWM control for LED driving
• Technology: patented spread-spectrum charge-transfer (transverse mode)
• Key outline sizes: 6 mm x 6 mm or larger (panel thickness dependent); widely different sizes and shapes possible
• Key spacings: 8 mm or wider, center to center (panel thickness dependent)
• Slider design: 2 to 8 keys placed in sequence, same design as keys
• Electrode design: two-part electrode shapes (drive-receive); wide variety of possible layouts
• PCB 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)
• Adjacent metal: compatible with grounded metal immediately next to keys
• Panel thickness: up to 3 mm glass, 2.5 mm plastic (key size dependent)
• Key sensitivity: individually settable via simple commands over l2C-compatible interface