QT240-ISSG

Overview

The QT240-ISSG is a 4-channel QTouch capacitive touch sensor IC designed for human-machine interfaces. 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 primary operating modes: a low-power sync mode consuming approximately 90µA at 4V, and a fast spread-spectrum mode drawing about 1.5mA at 4V. It utilizes charge-transfer technology with internal drift compensation and a detection integrator requiring six consecutive confirmations to trigger an output. The component is housed in a 20-SSOP package.

Feature Summary

• Four independent sensing channels capable of detecting touch or near-proximity through various dielectric materials
• Integrated signal processing algorithms including asymmetric drift compensation and consensus filtering for noise immunity
• Spread-spectrum modulation capability to minimize electromagnetic interference and enhance EMC compliance
• External synchronization support via the SYNC pin to suppress periodic noise sources such as mains frequency

Applications

• Instrument panels
• Gaming machines
• Access systems
• Pointing devices
• Appliance controls

Procurement Notes

Verify the specific ordering suffix against official Microchip documentation to ensure correct temperature range and feature configuration. Confirm availability status as distribution channels may list obsolete stock. Request RoHS compliance certificates and material declarations directly from authorized suppliers prior to procurement.

Selection Notes

Select this component for applications requiring robust capacitive sensing with minimal external components. Evaluate the trade-off between response time and power consumption when choosing between slow sync and fast spread-spectrum modes. Ensure the design accommodates the mandatory option resistors for recalibration timing settings and verify that unused channels are properly terminated with dummy capacitors.

Part Context

The QT240-ISSG belongs to the QTouch family of self-contained digital sensor ICs developed by Quantum Research Group, now part of Microchip Technology. These devices utilize proprietary charge-transfer technology to provide stable sensing under varying environmental conditions without requiring complex calibration routines during operation.

Replacement Considerations

No direct public substitute part numbers are confirmed for this discontinued model. Designers should evaluate newer QTouch series ICs for functional compatibility, ensuring interface requirements and channel counts align with the original system specifications.