QT115-D

Overview

The QT115-D is an 8-pin capacitive touch and proximity sensor IC from the QProx family, designed for high-sensitivity applications. It features variable gain controlled by the sample capacitor Cs and supports daisy-chaining via Sync In/Out pins to create multi-key panels. The device operates within a supply voltage range of 3V to 5.5V and includes a fixed recalibration timeout of 10 seconds. It utilizes a consensus filter length of 3 samples and offers a sensitivity range of 28fF to 1,000fF. The part is available in -I suffix variants for industrial temperature ranges.

Feature Summary

• Supports daisy-chaining for multi-touch panel configurations
• Variable sensitivity adjustment via external sample capacitor
• Fixed threshold detection with 6-count deviation
• Integrated synchronization pulses for interference-free operation

Applications

• Multi-key touch panels requiring adjacent electrode placement
• High-sensitivity proximity sensing through thick panels or windows
• Security monitoring systems requiring long-range detection
• Touch switches integrated into equipment control panels

Procurement Notes

Verify the specific package variant (DIP or SO8) and output polarity (-H suffix for active-high) against project requirements. Confirm that the -I suffix matches the required operating temperature range. Ensure power supply stability as fluctuations directly impact sensor performance and false triggering risks.

Selection Notes

Select the QT115 when high sensitivity and daisy-chaining capabilities are required. Choose based on the desired output logic level; use the standard version for active-low outputs or the -H variant for active-high outputs. Consider the trade-off between increased sensing range and higher power consumption compared to faster-response variants like the QT112.

Part Context

The QT115 is part of the QProx family of capacitive sensors manufactured by Quantum Research Group Ltd., now distributed by Microchip Technology. It serves as a specialized variant optimized for high-gain applications and multi-device chaining, distinguishing it from the standard QT110 and faster-response QT112 models.

Replacement Considerations

Direct functional replacements include the QT115H for active-high output requirements. For simpler single-key applications without chaining needs, the QT110 may be considered if lower sensitivity is acceptable.