QT60248-ASG

Overview

The QT60248-ASG is a 24-key QMatrix touch controller utilizing transverse charge-transfer sensing. It operates on a single +3V to +5V supply within an industrial temperature range of -40°C to +105°C. The device features a 32-pin lead-free TQFP package and communicates via an SPI slave interface. Key parameters include internal oscillator operation, detection integrators for noise immunity, and onboard EEPROM for setup storage.

Feature Summary

• Supports up to 24 keys with individually adjustable sensitivity and response time
• Enables detection through dielectric panels up to 50mm thick
• Includes adaptive auto self-calibration and drift compensation algorithms
• Features FMEA compliant continuous self-test and reporting diagnostics

Applications

• Automotive panels
• Machine tools
• ATM machines
• Appliance controls
• Security keypanels

Procurement Notes

Verify the specific ordering suffix ASG confirms the industrial temperature grade (-40°C to +105°C) and lead-free TQFP-32 packaging. Ensure the component matches the 24-key variant specifications rather than the 16-key alternative. Confirm that the datasheet revision aligns with current manufacturing standards before finalizing procurement orders.

Selection Notes

Select this model when a 24-key matrix configuration is required for harsh environments. It is suitable for applications needing sealed, watertight control panels immune to humidity or vandalism. Consider the QT60168 if only 16 keys are needed. Ensure the host system supports SPI communication and can handle the required calibration timing constraints.

Part Context

This component belongs to the QProx QT60168/QT60248 family of digital charge-transfer sensors. These ICs are designed specifically for scanned passive X-Y matrices. They allow arbitrary key shapes and sizes, supporting mixed layouts within a single panel while maintaining robust performance under varying environmental conditions.

Replacement Considerations

The QT60168-ASG serves as a functional substitute for designs requiring only 16 keys. Both devices share identical electrical characteristics and pinouts, differing solely in maximum supported key count. Verify that unused Y-lines are properly handled if substituting between these variants.

FAQ

How does the device handle key sensitivity adjustments?

Key sensitivity is set individually via simple functions over the serial port by a host microcontroller. Setup configurations are stored in onboard EEPROM and persist across power cycles.

What is the purpose of the FMEA tests in this IC?

FMEA tests provide continuous self-test and reporting diagnostics to ensure safe operation in critical applications. Tests run during dummy timeslots after enabled keys and report status via the serial interface.

Can different key sizes be used on the same panel?

Yes, key sizes and shapes can be mixed arbitrarily within a single panel. Surface areas can vary by a factor of 20:1 without affecting overall functionality.