ATMXT449TD-A: Touchscreen Controller

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The ATMXT449TD-A Automotive touchscreen controller is aimed at display sizes up to 8” used in center stacks, navigation systems or rear seat entertainment systems. This family of automotive touchscreen controller brings Microchip’s unmatched Adaptive Sensing technology to the Automotive market. It enables dynamic touch classification, a feature that automatically and intelligently switches between self- and mutual-capacitance sensing to provide users a seamless transition between a finger touch and glove touch. Adaptive Sensing is also resistant to water and moisture and ensures superior touch performance even in these harsh conditions.

In addition, the ATMXT449TD-A supports Hover operation, which tracks the position of the finger when it floats within 20mm of the touchscreen. Hover allows user interaction without making a physical contact, and brings a more dynamic interface to user applications.

Additional Features

Fully automotive-qualified (Grade 2), operating within the temperature range of -40 to +105 deg C

Supports up to 16 concurrent touches in real time with touch size reporting

Communication via a serial interface (I2C or SPI)

Integrated voltage doubler option to increase the signal to noise ratio (SNR)

Adaptive Sensing (Self and Mutual cap)

Supports thick glove (5mm) touch

Support thick lenses (up to 3mm plastic)

Superior moisture performance

Hover tracking up to 20mm

Package: TQFP100

Application Interfaces

• I2C-compatible interface with support for Standard mode (up to 100 kHz), Fast mode (up to 400 kHz),
Fast-mode Plus (up to 1 MHz), High-speed mode (up to 3.4 MHz)
• SPI interface (up to 8 MHz)
• Interrupt to indicate when a message is available
• SPI Debug Interface to read the real-time raw data for tuning and debugging purposes

Power Supply

• Digital (Vdd) 3.3 V nominal
• Digital I/O (VddIO) 3.3 V nominal
• Analog (AVdd) 3.3 V nominal
• High voltage internal X line drive (XVdd) 6.6 V with internal voltage pump (XVdd = Vdd if voltage pump not used)


• Up to 32 nodes can be allocated as mutual capacitance sensor keys (subject to other configurations)
• Adjacent Key Suppression (AKS) technology is supported for false key touch prevention

Schematic diagram : I2C Mode


Figure 1: I2C Schematic

Farees Ahmed

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