Si7005 Humidity and Temperature Sensor

Silicon laboratories have just release the Si7005, a digital relative humidity and temperature sensor. This monolithic CMOS IC integrates humidity and temperature sensor elements, an analog-to-digital converter, signal processing, calibration data and an I2C host interface. The patented use of industry-standard, low-K polymeric dielectrics for sensing humidity enables the construction of a low-power, monolithic CMOS sensor IC with low drift and hysteresis and excellent long term stability. Both the humidity and temperature sensors are factory-calibrated and the calibration data is stored in the on-chip non-volatile memory. This ensures that the sensors are fully interchangeable, with no recalibration or software changes required, simplifying designs and reducing end system manufacturing costs. The Si7005 humidity and temperature sensor is packaged in a 4 mm x 4 mm QFN package and is reflow solderable. The solution only requires 2 external SMD capacitors. Some of the key features are:

  • Relative Humidity Sensor: ± 4.5% RH (maximum @ 20–80% RH)
  • Temperature Sensor: ±0.5 ºC accuracy (typical) / ±1 ºC accuracy (maximum @ 0 to 70 °C)
  • 0 to 100% RH operating range
  • –40 to +85 ºC (-GM – wide temp range version)
  • 0 to +70 ºC operating range (-FM – normal temp range version)
  • Wide operating voltage range (2.1 to 3.6 V)
  • Low Power Consumption: 240 μA during RH conversion
  • I2C host interface