SX8644I05AWLTRT Semtech, SX8644I05AWLTRT Datasheet - Page 14

• Manufacturer Part Number: SX8644I05AWLTRT
• Description: 12-ch Capacitive Touch Solution (Button & Slider)
• Manufacturer: Semtech

SX8644
Ultra Low Power, Capacitive Button and Slider
Touch Controller (12 sensors) with Enhanced LED Drivers
ADVANCED COMMUNICATIONS & SENSING
DATASHEET
3.5 Sensors on the PCB
The capacitive sensors are relatively simple copper areas on the PCB connected to the twelve SX8644 capacitive
sensor input pins (CAP0…CAP11).The sensors are covered by isolating overlay material (typically 1mm...3mm).
The area of a sensor is typically one square centimeter which corresponds about to the area of a finger touching
the overlay material.
The capacitive sensors can be setup as ON/OFF buttons (see example Figure 9) or arranged in a slider
configuration (see example Figure 10) for e.g. menu scrolling or volume control applications.
layer of four sensors for buttons
Figure 9 PCB top
(surrounded by a ground plane)
PCB top layer of one slider using six sensors
Figure 10
(surrounded by ground plane)
Revision 7_3, January 10
© 2009 Semtech Corp.
www.semtech.com
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