The QT220 is a self-contained digital sensor IC capable of detecting near-proximity or touch on 2 electrodes. It allows electrodes to project independent sense fields through any dielectric like glass, plastic, stone, ceramic, and wood. It can also turn metal-bearing objects into intrinsic sensors, making them responsive to proximity or touch. This capability coupled with its continuous self-calibration feature can lead to entirely new product concepts, adding high value to product designs. Each of the channels operates independently of the other, and each can be tuned for a unique sensitivity level by simply changing its sample capacitor value. Two speeds are supported, one of which consumes only 90µA of typical current at 4V. Unique among capacitance sensors, the device incorporates spread spectrum modulation for unsurpassed EMC compliance. The devices are designed specifically for human interfaces, like control panels, appliances, gaming devices, lighting controls, or anywhere a mechanical switch or button may be found; they may also be used for some material sensing and control applications. These devices feature a SYNC pin which allows for synchronization with additional similar parts and/or to an external source to suppress interference.
The QT220 is a burst‑mode digital charge‑transfer sensor IC designed for touch controls. It integrates all hardware and signal‑processing functions needed for stable sensing, supports two independent channels, and offers features such as spread‑spectrum operation, external synchronization, and auto‑recalibration.
The document describes the device’s pin configuration, wiring recommendations, sensitivity adjustment methods, available options (speed, timeout, toggle), synchronization techniques, and circuit guidelines including power‑supply requirements and PCB layout tips. It also details the internal signal‑processing algorithms, drift compensation, and detection integrator behavior.
| Supply voltage | 3.9 V – 5.5 V |
|---|---|
| Package | 20‑SSOP, Pb‑free |
| Slow‑mode current consumption | ≈90 µA @ 4.0 V |
| Threshold level | 12 counts |
| Hysteresis | 2 counts (17 %) |
| Max On‑Duration options | 10 s, 60 s, infinite |
| Fast‑mode response time | ~40 ms typical |
| Slow‑mode response time | ~100 ms |
The QT220 operates from a single supply voltage between 3.9 V and 5.5 V.
Sensitivity can be changed by altering the value of the channel’s Cs capacitor, using larger electrode areas, reducing panel thickness, or selecting a material with a higher dielectric constant.
The QT220 provides three Max On‑Duration timeout settings: 10 seconds, 60 seconds, or infinite.
In slow mode the device draws about 90 µA at 4.0 V, while in fast mode it consumes roughly 1.5 mA at the same voltage.