QT150-AS

Overview

The AT42QT150-AS is a 5-key capacitive touch sensor IC from Microchip Technology's QProx QT140/150 series. It operates on a single 3V to 5.5V supply with a typical current consumption of 5mA. The device features five independent sensing channels, each requiring only one external capacitor for operation. It supports open-drain or push-pull outputs and includes Adjacent Key Suppression (AKS) to prevent false triggers from large fingers or water films. The IC provides automatic self-calibration, drift compensation, and a synchronization pin for multi-chip systems. It is available in SSOP-28 packaging and functions within an industrial temperature range of -40°C to +105°C.

Feature Summary

• Independent channel operation with per-channel sensitivity adjustment via external sample capacitors
• Patent-pending AKS™ Adjacent Key Suppression to suppress weaker signals from adjacent keys
• Continuous self-calibration and asymmetric drift compensation for stable performance under varying environmental conditions
• Bidirectional SYNC I/O pin enabling time-aligned synchronization across multiple chips or external noise sources

Applications

• Instrument panels and appliance controls
• Gaming machines and security systems
• Access systems and pointing devices
• PC peripherals and backlighted buttons

Procurement Notes

Verify the specific ordering suffix against the manufacturer's official documentation to confirm package type and temperature rating. Ensure the selected variant matches the required operating environment and interface configuration. Cross-reference the datasheet revision history for any recent design or assembly changes that may affect compatibility.

Selection Notes

Select this component when a compact solution for up to five touch inputs is required without complex signal processing overhead. Consider the SSOP-28 package constraints and the need for external sample capacitors ranging from 1nF to 200nF. Evaluate the requirement for AKS functionality if keys are densely spaced or exposed to moisture.

Part Context

The QT150 is part of the QProx QT140/150 family, which utilizes charge-transfer technology for robust capacitive sensing. This series is designed to replace mechanical switches in human-machine interfaces, offering high reliability and resistance to environmental interference through digital signal processing techniques.

Replacement Considerations

Direct replacements include the QT140-AS for 4-key applications or other members of the QTouch/QProx family such as the AT42QT1010 for single-key needs. Verify pinout compatibility, as DIP and SSOP pinouts differ significantly within this family.