Azoteq IQS231A & IQS231B ProxSense SAR Controllers

Azoteq IQS231A and IQS231B ProxSense® SAR Controllers are single-channel capacitive proximity/touch controllers, designed for applications where an awake/activate on the proximity function are required. The IQS231A and IQS231B are ultra-low-power solutions that use unique release and/or movement detection for applications that require long-term detection. The IQS231A and IQS231B operate standalone or I2C and feature configuration via OTP (One Time Programmable) bits. Switching from I2C to standalone during runtime is also possible in order to access all settings while offering the simplicity of a standalone output.


  • Integrated SAR user interface offering a simple GPIO output
  • Quick-release detection – effectively prevent false triggers
  • Quick-release sensitivity options 
  • Wide range of control for sensing in high power RF environments
  • Pin compatible with IQS128 and IQS229
  • 1.75V to 3.6V Input voltage, trimmed to use proximity detection with 1.8V digital interface
  • External threshold adjustment pin (minimize need for pre-empted OTP adjustments)
  • Standalone failsafe mode (backward compatible failsafe output, short pulses on output to indicate operational device)
  • Default OTP options focus on safety and passing SAR lab qualification, OTP changes offer performance advantages
  • I2C interface option (improved compatibility)
  • Extended controls in I2C mode (setup in I2C, runtime with standalone output)
  • Minimal external components (direct input strap) 
  • Optional input for synchronized implementations (input to instruct IC when to sense)
  • Synchronization output – Failsafe pulses may be used by the master to synchronize on, with sensing after each pulse 
  • Synchronization input – Sensing is only done while Sync input is low
  • Low power sensing: 30Hz (default), 100Hz, 8Hz, 4Hz (sub 6uA mode) 
  • Constant sampling rates during all power modes with rapidly debounced output changes
  • Advanced temperature compensation option


  • Specific Absorption Rate (SAR) applications
  • Integrated hybrid designs (RF and capacitive sensing combined) 
  • Movement sensing applications (user interaction detection, anti-theft)
  • Hold detection for screen activation
  • On-ear detection
Published: 2012-02-29 | Updated: 2022-03-11