ATMXT224E-ATR

Overview

The ATMXT224E-ATR is an automotive-grade capacitive touchscreen controller from the maXTouch family, designed for up to 224 channels. It supports true 12-bit multitouch with independent XY tracking for ten concurrent touches and touch size reporting. The device operates on dual-rail power (VDD and AVDD) ranging from 2.7 V to 3.3 V nominal. It features an I²C-compatible slave interface operating at 400 kHz and includes advanced signal processing for noise suppression and drift compensation. The component is qualified to AEC-Q100 Grade 3 standards, ensuring reliability in harsh environments.

Feature Summary

• Supports up to 224 channels with flexible electrode configurations including 16x14 native mode and extended modes up to 22x8.
• Provides true 12-bit multitouch performance with independent XY tracking for ten simultaneous touches.
• Includes advanced digital filtering, auto drift compensation, and palm touch recovery algorithms.
• Operates within a temperature range of -40°C to +85°C and meets AEC-Q100 Grade 3 automotive qualification.

Applications

• Automotive infotainment systems requiring robust capacitive touch interfaces.
• Industrial control panels operating in extreme environmental conditions.
• Medical devices needing reliable multitouch input with high noise immunity.
• Consumer electronics utilizing PET or glass sensors with varying stackup thicknesses.

Procurement Notes

Verify the specific ordering suffix against the manufacturer's current documentation to ensure correct package and temperature grade alignment. Confirm that the required bypass capacitors are X7R or X5R types placed within five millimeters of the chip pins. Check for any product change notifications that may affect pinout or electrical characteristics prior to final design approval.

Selection Notes

Select this model when a maximum of 224 sensing nodes is required with automotive reliability standards. Ensure the application supports dual-rail power supplies between 2.7 V and 3.3 V. Verify that the host system can accommodate the I²C interface speed and that the sensor layout matches one of the supported matrix configurations. Consider the need for stylus support or glove operation if applicable to the end-use environment.

Part Context

This component belongs to the Atmel maXTouch MXT224 series, which utilizes QMatrix technology for mutual capacitance sensing. The E variant denotes the automotive grade version, distinguished by its qualification to AEC-Q100 Grade 3 standards compared to commercial variants. The part integrates a dedicated capacitive touch engine and microsequencer coprocessors for efficient signal acquisition and processing.

Replacement Considerations

Direct replacements must match the 48-pin TQFP package and 224-channel capacity. Verify compatibility with existing firmware protocols as the Object Protocol may differ between generations. Ensure the substitute component supports the same dual-rail power requirements and I²C interface specifications without requiring hardware redesign.

FAQ

What is the maximum number of concurrent touches supported?

The device supports up to ten concurrent touches with independent XY tracking and touch size reporting.

Can the Y lines be used as X drivers?

Yes, in extended modes, Y lines Y8 through Y13 can be reassigned as X drive lines, requiring a 100 Ω resistor for modes 21x9 and 22x8.

Is an external oscillator required?

No, the device contains an internal oscillator and does not require an external clock source.

How is unintentional touch suppressed?

The device uses the Touch Suppression T42 object to filter out false detections from large body areas like palms or cheeks.