Capacitive Touch Sensor IC

Capacitance is an amazingly accurate way to measure everything from physical contact to length or pressure. While capacitance sensors typically require a fair amount of circuitry, we now have one in a single IC with an I2C digital interface. Make tactile switches obsolete!

Features:

• Accuracy: 4 fF (yes femto)
• Linearity: 0.01%
• Common-mode (not changing) capacitance up to 17 pF
• Full-scale (changing) capacitance range: ±4 pF
• Tolerant of parasitic capacitance to ground up to 60 pF
• Update rate: 10 Hz to 90 Hz
• Simultaneous 50 Hz and 60 Hz rejection at 16 Hz
• Temperature sensor on-chip
  Resolution: 0.1°C, accuracy: ±2°C
• Voltage input channel
• Internal clock oscillator
• 2-wire serial interface (I2C®-compatible)
• Power
  2.7 V to 5.25 V single-supply operation
  0.7 mA current consumption
• Operating temperature: –40°C to +125°C
• 16-lead TSSOP package

Documents: AD7746 Datasheet