QT60040-ISG

Overview

The QT60040-ISG is a CMOS charge-transfer sensor IC designed for matrix touch controls, supporting up to four keys in a 4x1 configuration. It operates on a single power supply ranging from 2.5V to 5.5V with typical supply currents of 0.6mA at 3V and 1.5mA at 5V. The device features four active-high outputs capable of sensing up to two simultaneous key presses. It includes self-calibration, drift compensation, and detection integration algorithms to ensure stability under varying environmental conditions. The component is housed in a 14-pin SOIC package and supports an operating temperature range of -40°C to +85°C.

Feature Summary

• Transverse charge-transfer technology enables detection through various dielectric materials using a simple 4x1 matrix geometry.
• Integrated signal processing provides full self-calibration and asymmetric drift compensation for long-term reliability.
• Configurable options allow selection between single-key or dual-key rollover modes and adjustable recalibration timeouts.

Applications

• Automotive control interfaces
• ATM machine keypads
• Industrial keyboards and security panels

Procurement Notes

Verify the specific suffix 'IS' confirms the industrial temperature rating (-40°C to +85°C) and SOIC-14 package variant. Confirm that the manufacturer designation aligns with Quantum Research Group (QProx) specifications, as Microchip Technology may distribute or license this legacy product line. Ensure the ordering information matches the exact part number requirements for your design.

Selection Notes

Select this component when a robust, low-component-count solution for sealed touch interfaces is required. The shared capacitor architecture minimizes external parts compared to per-key sensors. Consider the 4x1 matrix limitation if more than four inputs are needed. Evaluate the need for ITO electrodes if backlighting or transparent panel integration is desired for the application.

Part Context

The QT60040 utilizes patented transverse charge-transfer technology developed by Quantum Research Group. It represents a cost-effective alternative to rubber membrane switches by allowing custom PCB-based electrode designs. The device is optimized for environments requiring watertight, vandal-proof, or chemically resistant control panels where traditional mechanical switches would fail.

Replacement Considerations

Publicly confirmed substitute part numbers are not available in the provided documentation. Designers should consult official QProx/Quantum resources for direct replacements or updated family members.

FAQ

How does the QT60040 handle false detections caused by environmental changes?

The device employs a drift compensation algorithm that tracks raw signals slowly when no touch is detected. This adjusts the reference level and threshold in real-time to account for capacitance changes over time without ignoring legitimate touches.

What is the maximum number of keys that can be sensed simultaneously?

The default configuration allows sensing up to two keys simultaneously. This can be restricted to only one key at a time by connecting the OPT1 pin to ground.

How is the sensitivity of the touch keys adjusted?

Sensitivity is primarily set by the value of the single external sampling capacitor (Cs). Typical values range from 22nF to 220nF, with 47nF being a common starting point depending on panel thickness and electrode geometry.