QT102-ISG

Overview

The QT102-ISG is a single-key capacitive touch controller utilizing QTouch™ spread-spectrum charge-transfer technology. It operates within a voltage range of 2V to 5.5V, consuming 23µA at 2V. The device features a toggle output mode with programmable auto-off delays and external sustain/cancel functions. It includes self-calibration, drift compensation, and noise filtering for reliable sensing through panels up to 50mm thick. The component is housed in a compact SOT-23-6 package (3x3mm) and supports active high or low hardware-configurable outputs.

Feature Summary

• Patented spread-spectrum charge-transfer technology ensures stable sensing under varying environmental conditions.
• Integrated power management with programmable auto-off delay ranging from minutes to hours.
• Hardware-configurable output polarity and external override capabilities for sustain and cancel functions.
• Automatic self-calibration and asymmetric drift compensation maintain sensitivity over time.

Applications

• Power switch replacement in countertop appliances
• Battery-powered toys and small electronics
• Heaters and lighting controls
• Automotive interior lighting systems

Procurement Notes

Verify the specific suffix ISG confirms the industrial temperature range of -40°C to +85°C and the SOT-23-6 package type. Confirm RoHS compliance status matches current manufacturing standards. Ensure the datasheet revision corresponds to version 2.3 or later for accurate timing specifications. Cross-reference pinout diagrams with PCB layout requirements before finalizing procurement orders.

Selection Notes

Select this component for applications requiring a single toggle input with automatic shutdown features. Evaluate panel thickness and material dielectric constants to determine appropriate sample capacitor values. Consider the required response time versus power consumption trade-offs when sizing the Cs component. Verify that the load capacitance remains within limits to prevent gain degradation.

Part Context

The QT102 belongs to the QTouch™ family of capacitive touch controllers designed for simple interface solutions. It complements more complex multi-key sensors by offering a low-cost, minimal-component solution for basic on/off control. The device integrates signal processing directly, reducing the need for external microcontrollers in simple power control tasks.

Replacement Considerations

Publicly confirmed substitute part numbers are not available in the provided documentation. Designers should evaluate other single-channel QTouch devices if pin compatibility or feature sets differ significantly.

FAQ

How is the auto-off delay configured?

The delay can be set using predefined hardwired connections to Vss, Vdd, or OUT, or programmed via an external RC network connected to the TIME and SNS pins.

What is the purpose of the Rs resistor?

The series resistor Rs, typically 4.7kΩ to 33kΩ, suppresses electrostatic discharge (ESD) and electromagnetic interference (EMI) effects on the sense line.

How does the device handle signal drift?

The QT102 uses asymmetric drift compensation where the reference level tracks the raw signal slowly when no detection occurs, adjusting faster for decreasing signals than increasing ones.