SX9300 Proximity Specific Absorption Rate Controll

By Semtech 231

SX9300 Proximity Specific Absorption Rate Controll

Semtech's SX9300 is the world’s first dual-channel capacitive Specific Absorption Rate (SAR) controller that accurately discriminates between an inanimate object and human body proximity. The resulting detection is used in portable electronic devices to reduce and control radio-frequency (RF) emission power in the presence of a human body, enabling significant performance advantages for manufacturers of electronic devices with electro-magnetic radiation sources to meet stringent emission regulations' criteria and Specific Absorption Rate (SAR) standards. Operating directly from an input supply voltage of 2.7 to 5.5 V, the SX9300 outputs its data via a 1.65 – 5.5 V host-compatible I2C serial bus.

The I2C serial communication bus port is compatible with 1.8 V host control to report body detection/proximity and to facilitate parameter settings adjustment. Upon proximity detection, the NIRQ output asserts, enabling the user to either determine the relative proximity distance, or simply obtain an indication of detection.

The SX9300 includes an on-chip auto-calibration controller that regularly performs sensitivity adjustments to maintain peak performance over a wide variation of temperature, humidity and noise environments, providing simplified product development and enhanced performance. A dedicated transmit enable (TXEN) pin is available to synchronize proximity measurements to RF transmission, enabling very-low supply current and high noise immunity by only measuring proximity when requested.

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  • 2.7 – 5.5 V input supply voltage
  • Dual SAR capacitive sensor inputs
    • On-chip SAR engine for body versus inanimate object
    • Detection
    • Stable proximity sensing with temperature
    • 20mm detection distance
    • Capacitance offset compensation to 30 pF
  • Active sensor guarding
  • Automatic calibration
  • Ultra-low-power consumption:
    • Active mode: 170 μA
    • Doze mode: 18 μA
    • Sleep mode: 2.5 μA
  • 400 KHz I2C serial interface
    • Four programmable I2C sub-addresses
    • Input levels compatible with 1.8 V host processors
  • Open-drain NIRQ interrupt pin
  • Three (3) reset sources: POR, NRST pin, Soft Reset
  • -40°C to +85°C operation
  • Compact size: 3 x 3 mm thin QFN package
  • Pb- and Halogen-free, RoHS/WEEE compliant
  • SAR compliant systems
  • Notebooks
  • Tablets
  • Mobile phones
  • Mobile hot spots