QT140-AS

Overview

The Microchip Technology QT140-AS is a digital charge-transfer capacitive touch sensor IC featuring four independent sensing channels. It operates on a single 3V to 5.5V supply with a typical current consumption of 5mA. The device utilizes a 28-pin SSOP package and supports an operating temperature range from -40°C to +105°C. Each channel requires only one external sample capacitor for operation, allowing for flexible sensitivity tuning. The IC includes internal signal processing for drift compensation and detection integration.

Feature Summary

• Independent sensing channels with individual logic outputs
• Patent-pending Adjacent Key Suppression (AKS) technology
• Continuous self-calibration for long-term stability
• Bidirectional synchronization pin for multi-chip systems

Applications

• Instrument panels
• Gaming machines
• Access systems
• Appliance controls
• Security systems

Procurement Notes

Verify the specific suffix 'AS' against official documentation to confirm the extended industrial temperature rating (-40°C to +105°C). Ensure the SSOP-28 package footprint matches the design requirements, as DIP pinouts differ significantly. Confirm RoHS compliance status through the manufacturer's latest environmental declarations before finalizing procurement.

Selection Notes

Select this component for applications requiring robust touch sensing under varying environmental conditions due to its wide temperature range. The inclusion of AKS makes it suitable for densely packed key arrays. Evaluate the need for synchronization if multiple units are deployed in close proximity to prevent cross-interference during simultaneous operation.

Part Context

The QT140-AS belongs to the QProx QT140/QT150 family of charge-transfer sensor ICs. This series is designed specifically for human-machine interfaces where mechanical switches are undesirable. The 'AS' variant denotes the industrial temperature grade, distinguishing it from commercial variants like the QT140-D which operate within a narrower temperature range.

Replacement Considerations

Publicly confirmed substitute part numbers are not available in the provided documentation. Designers should consult Microchip Technology directly for qualified alternatives or updated product line recommendations.