QT240-ISS

Overview

The QT240-ISS is a 4-channel QTouch capacitive sensor IC utilizing charge-transfer technology. It operates on a single supply voltage ranging from 3.9V to 5.5V and features four independent sensing channels with active-high outputs. The device supports two acquisition modes: a low-power sync mode consuming approximately 90µA at 4V, and a fast spread-spectrum mode drawing about 1.5mA. It includes built-in drift compensation, a detection integrator requiring six consecutive confirmations, and strap-selectable recalibration timeouts of 10s, 60s, or infinite. The component is housed in a 20-SSOP package.

Feature Summary

• Charge-transfer technology enabling projection through various dielectrics
• Independent channel sensitivity adjustment via sample capacitors
• Spread-spectrum modulation for enhanced EMC compliance
• Continuous self-calibration and drift compensation algorithms

Applications

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

Procurement Notes

Verify the specific suffix against official documentation to confirm temperature range and lead-free status. Confirm current availability as distribution status may change. Ensure the design accommodates mandatory option resistors and sample capacitors for proper operation.

Selection Notes

Select between slow and fast modes based on power constraints and response time requirements. Fast mode enables spread-spectrum operation but increases current consumption. Unused channels require dummy capacitors and series resistors to maintain correct functionality.

Part Context

This component belongs to the QTouch family of capacitive touch sensors developed by Quantum Research Group and acquired by Microchip Technology. It represents an evolution in charge-transfer sensing designed to replace mechanical switches in human-machine interfaces.

Replacement Considerations

QT240-ISS-G is the lead-free variant of this component.