Introduction

The AT42QT1110 (QT1110) is a digital burst mode charge-transfer (QT™) capacitive sensor driver designed for any touch-key applications.

The keys can be constructed in different shapes and sizes. Refer to the Touch Sensors Design Guide and Application Note QTAN0002, Secrets of a Successful QTouch Design, for more information on construction and design methods (both downloadable from the Atmel website).

Features

● Sensor Keys:

● Up to 11 QTouch® channels

● Data Acquisition:

● Measurement of keys triggered either by a signal applied to the SYNC pin or

at regular intervals timed by the AT42QT1110 internal clock

● Keys measured sequentially for better performance, or in parallel groups for

faster operation

● Raw data for key touches can be read as a report over the SPI interface

● Discrete Outputs:

● Configurable “Detect” outputs indicating individual key touch (7-key mode)

● Device Setup:

● Device configuration can be stored in EEPROM

● Technology:

● Patented spread-spectrum charge-transfer (direct mode)

● Key Outline Sizes:

● 6 mm × 6 mm or larger (panel thickness dependent); widely different sizes and

shapes possible, including solid or ring shapes

● Key Spacings:

● 7 mm center-to-center or more (panel thickness dependent)

● Layers Required:

● One

● 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:

● Individually settable via simple commands over serial interface

● Adjacent Key Suppression® (AKS®)

● Patented AKS technology to enable accurate key detection

● Interface:

● Full-duplex SPI slave mode (1.5 MHz), CHANGE pin, discrete detection

outputs

● Moisture Tolerance

● Increased moisture tolerance based on hardware design and firmware tuning

● Power:

● 3 V – 5.5 V

● Package:

● 32-pin 5 × 5 mm MLF RoHS compliant

● 32-pin 7 × 7 mm TQFP RoHS compliant

● Signal Processing:

● Self-calibration, auto drift compensation, noise filtering, AKS technology

● Applications:

● Specific package qualified for automotive applications, such as radio, keyless entry, electric windows and satellite navigation