Introduction
●The AT42QT1040 (QT1040) is a digital burst mode charge-transfer (QT™) capacitive sensor driver designed for touch-key applications. The device can sense from one to four keys; one to three keys can be disabled by not installing their respective sense capacitors. Any of the four channels can be disabled in this way.
●The device includes all signal processing functions necessary to provide stable sensing under a
●wide variety of changing conditions, and the outputs are fully debounced. Only a few external
●parts are required for operation.
●The QT1040 modulates its bursts in a spread-spectrum fashion in order to heavily suppress the
●effects of external noise, and to suppress RF emissions.
●Features
●• Number of Keys:
●– Up to 4
●• Discrete Outputs:
●– 4 discrete outputs indicating individual key touch
●• Technology:
●– Patented spread-spectrum charge-transfer (direct mode)
●• Electrode Design:
●– Simple self-capacitance style (refer to the Touch Sensors Design Guide)
●• Electrode Materials:
●– Etched copper, silver, carbon, Indium Tin Oxide (ITO)
●• Electrode Substrates:
●– PCB, FPCB, plastic films, glass
●• Panel Materials:
●– Plastic, glass, composites, painted surfaces (low particle density metallic paints possible)
●• Panel Thickness:
●– Up to 10 mm glass, 5 mm plastic (electrode size dependent)
●• Key Sensitivity:
●– Fixed key threshold, sensitivity adjusted via sample capacitor value
●• Adjacent Key Suppression™
●– Patented Adjacent Key Suppression™ (AKS™) technology to enable accurate key detection
●• Interface:
●– Pin-per-key outputs, plus debug mode to observe sensor signals
●• Moisture Tolerance:
●–Good
●• Power:
●– 1.8V ~ 5.5V
●• Package:
●– 20-pin 3 x 3 mm VQFN RoHS compliant
●• Signal Processing:
●– Self-calibration, auto drift compensation, noise filtering, Adjacent Key Suppression technology
●• Applications:
●– Mobile, consumer, white goods,toys, kiosks, POS, and so on
