Azoteq IQS211x ProxSense® ICs

Azoteq IQS211x ProxSense® ICs are single-channel capacitive proximity/touch controllers with movement detection. These self-capacitance controllers are designed for applications where an awake/activate on proximity/touch function is required. The IQS211x ICs use movement detection for applications that require long-term detection. These devices operate standalone or by I2C control and can be configured via OTP (One Time Programmable) bits.

The IQS211B offers alternate hardware with identical firmware to the IQS211A, with an improved temperature response and wider -40°C to 85°C operating temperature range.


  • Charge-transfer capacitance measurement technology (Analog ProxSense® Engine)
  • Finite state machine to automate detection and environmental compensation without MCU interaction (integrated microprocessor)
  • Self-capacitance measurements
  • Signal conditioning to provide signal gain (Analog – Capacitive offset calibration)
  • Signal conditioning to provide offset compensation for parasitic capacitance (Analog – Capacitive offset calibration)
  • Integrated calibration capacitors (Analog – Capacitive offset calibration)
  • Integrated timer for timer triggered conversions
  • Integrated LDO regulator for increased immunity to power supply noise
  • Integrated oscillator
  • Processing logic to perform measurement filtering, environmental compensation, threshold detection, and movement detection


  • Wearable devices
  • Movement detection devices (fitness, anti-theft)
  • White goods and appliances
  • Proximity activated back lighting
  • Applications with long-term activation
  • Human interface devices


  • Pin compatible with IQS127/128/227/228/231A
  • Automatic Tuning Implementation (ATI)
  • On-chip movement detection algorithm
  • Forced activation when movement detected
  • Minimal external components
  • 25mm detection distance
  • Up to 200pF sensor load
  • I2C interface
    • Standard I2C (polling)
    • I2C (polling) configuration at start-up with standalone runtime operation
    • I2C with wake-up
  • Standalone interfaces
    • Dual output: Fixed threshold activation output & movement output
    • Dual output: Movement latch & movement output
  • Movement output & digital input
  • 1-Wire streaming interfaces
    • 1-Wire data streaming & movement output
    • 1-Wire & CLK signal
  • Special configurations
    • Activation based on capacitive load at power-on
    • Automatic threshold adjustment
  • Movement output selection
    • Pulse Frequency Modulation (PFM, default), Pulse Width Modulation (PWM), Latched, PWM combined with activation
  • Internal Capacitor Implementation (ICI)
  • Low power consumption: Sub-2uA modes available
  • Low power options
    • Low power without activation
    • Low power within activation
    • Low power standby modes with proximity wake-up
  • Supply voltage: 1.8V to 3.6V
  • Operating temperature range
    • IQS211A: -20°C to +85°C
    • IQS211B: -40°C to +85°C


Functional Block Diagram

Block Diagram - Azoteq IQS211x ProxSense® ICs
Published: 2014-11-21 | Updated: 2023-01-05