Microchip Technology AT42QT2120 QTouch 12-Channel Touch Sensor IC

Microchip AT42QT2120 QTouch 12-Channel Touch Sensor IC is a new capacitive touch controller for buttons, sliders, and wheels that delivers the longest capacitive proximity sensing range in the market today, stretching more than 10 inches (25cm). This longer range for the AT42QT2120 QTouch 12-Channel Touch Sensor IC, combined with other standard touch advantages—in noise immunity, Adjacent Key Suppression® (AKS®), conducted immunity, reduced BOM, and moisture tolerance—make Microchip the premier supplier for capacitive touch user interfaces. The new capacitive touch sensing algorithm in the Microchip AT42QT2120 QTouch 12-Channel Touch Sensor IC enables superior sensing because of faster acquisition times and shorter burst lengths that provide superior sensing range.


  • Number of Keys:
    • Comms Mode: 1 to 12 keys (1 to 9 if wheel or slider option enabled)
    • Standalone Mode: 1 to 5 keys
  • Technology: Patented spread-spectrum QTouchADC charge-transfer
  • Number of Output Lines:
    • Comms Mode: Up to 10 channels can be configured as outputs (but they will replace the keys)
    • Standalone Mode: 1 to 5 channels can be configured as outputs
  • Key Outline Sizes: 5mm x 5mm or larger (panel thickness dependent)
  • Key Spacings: 6mm or wider, center to center (panel thickness, human factors dependent)
  • Key Design: Single solid or ring-shaped electrodes; widely different sizes and shapes possible
  • Wheel Size: Typically 30mm- 50mm diameter
  • Wheel Electrode Design:
    • Spatially interpolated wheel up to 80mm diameter
    • Typical width of segments 12mm
  • Signal Processing: Self-calibration, Auto drift compensation, Noise filtering, Adjacent Key Suppression® (AKS®)
  • Moisture Tolerance: Good
  • Power: 1.8V to 5.5V
  • Slider Electrode Design:
    • Spatially interpolated, resistorless design
    • Typical length 50mm-100mm, typical width 12mm
    • Can be an arc or other irregular shape
  • Substrates: FR-4, low-cost CEM-1 or FR-2 PCB materials, polyamide FPCB; PET films, glass
  • Adjacent Metal: Compatible with grounded metal immediately next to keys
  • Layers Required: One; electrodes and components can be on the same side
  • Electrode Metals: Etched copper, silver, carbon, indium tin oxide (ITO), PEDOT
  • Panel Materials: Plastic, glass, composites, painted surfaces (nonconductive paints)
  • Key Panel Thickness:
    • Up to 15mm glass (key size dependent)
    • Up to 10mm plastic (key size dependent)
  • Wheel/slider Panel Thickness:
    • Up to 4mm glass
    • Up to 3mm plastic
  • Key Sensitivity:
    • Comms Mode - individually settable via simple commands over an I2C-compatible interface
    • Standalone Mode - settings are fixed
  • Interface:
    • I2C-compatible slave mode (400kHz)
    • CHANGE status indication pin


  • Proximity Sensing
  • Wake-Up Thermostat
  • TV Controls
  • Wireless Mouse
Published: 2012-02-15 | Updated: 2022-03-11