​Si7005 Digital Relative Humidity and Temperature Sensor

Note: the Si7005 devices remain in production, but are not recommended for new designs. For new designs, please use the 2nd generation Si701x/2x Humidity Sensors instead.

The Si7005 digital relative humidity and temperature sensor integrates humidity and temperature sensor elements, an analog-to-digital converter and signal processing in a single monolithic CMOS sensor IC. Both the humidity and temperature sensors are factory-calibrated and the calibration data is stored in on-chip non-volatile memory. The Si7005 humidity and temperature sensor is packaged in a 4 mm x 4 mm QFN package and is reflow solderable.
 
 

Features

  • 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
  • Up to -40 to +85 °C operating range
  • Wide operating voltage range (2.1 to 3.6 V)
  • Low Power Consumption: 240 μA during RH conversion
  • I2C host interface
  • Integrated on-chip heater
  • 4 mm x 4 mm QFN package
  • Excellent long term stability
  • Factory calibrated
  • Optional factory-installed filter/cover
    • Low-profile
    • Protection during reflow
    • Excludes liquids and particulates (hydrophobic/oleophobic)
 
 

Applications

Product Matrix
Zoom
Part NumberDescriptionTemp. Accuracy (max)RH Accuracy (max)Temperature RangeFilter CoverPackage FormatPackage Type
Si7005-B-FMDigital RH and temperature sensor IC±1 °C±4.5%0 to 70 °CNoTubeQFN24
Si7005-B-FM1RDigital RH and temperature sensor IC with pre-installed protective cover±1 °C±4.5%0 to 70 °CYesTape and ReelQFN24
Si7005-B-GMDigital RH and temperature sensor IC±1 °C±4.5%-40 to 85 °CNoTubeQFN24
Si7005-B-GM1RDigital RH and temperature sensor IC with pre-installed protective cover±0.5 °C±4.5%-40 to 85 °CYesTape and ReelQFN24

Si7005 Humidity Readings

Si7005 Humidity and Temperature SensorThe Si7005 humidity and temperature sensor is rated at ±3% typical, ±4.5% max relative humidity accuracy, and ±0.5 °C temperature accuracy. It is one of the lowest power humidity sensors available, making it ideal for battery-powered applications, consuming only 240 µA during a relative humidity measurement. The device operates by allowing air to come into contact with an exposed polyimide sensor, through an opening in the packaging, shown here. Moisture in the air causes a capacitance change to occur in the polyimide sensor, and the on-chip signal conditioning converts this capacitance to a humidity reading, made available to the user over the I2C interface.
 
 
 

Plug-n-play Solution - No Manual Calibration Needed

Si7005 Humidity and Temperature SensorThe Si7005 humidity and temperature sensor requires few external components – only 2 surface mount capacitors, much less than traditional discrete resistive or capacitive sensor circuits. This highly integrated device reduces the amount of board space, complexity, and cost required for a relative humidity and temperature sensor solution. The Si7005 humidity and temperature sensor is a “Plug-and-play” solution compared to the lengthy discrete design engineering effort and manual calibration required by discrete humidity sensing solutions. Some humidity sensors and modules may require customers to perform a per-device calibration during manufacturing. Silicon Labs calibrates each Si7005 humidity and temperature sensor, and stores the calibration data in the device’s non-volatile flash memory. No external calibration circuitry is required, simplifying designs and reducing end system manufacturing costs.
 
 
 

Alternative Protective Filters

Most humidity sensors require protection from contaminants onto the exposed sensor. Some existing devices require placing protective tape over the package cavity for protection during board assembly, and subsequent removal, and addition of a plastic filter cover after assembly to protect the device during field use. These additional components and steps are costly and inconvenient for manufacturers to implement, but are unnecessary with the Si7005 humidity and temperature sensor.
Humidity and Temperature Sensor Filter Covers 
 
 
 

Si7005 Humidity and Temperature Sensor Pre-Installed Protective FilterSi7005 Humidity and Temperature Sensor Protective Filter Cover

Silicon Labs offers the Si7005 humidity and temperature sensor with a thin hydrophobic filter/cover pre-installed, to protect the exposed sensor. The protective filter/cover provides protection during board assembly, eliminating the cost and inconvenience of adding and removing tape on the device. It should be left on the product eliminating the need to add any post-assembly protective covers. Air passes through the filter cover, while particles are filtered out.
 
 
 

Si7005 Humidity and Temperature Sensor Example Source Code and Drivers

Example demo source code, Linux, and Android drivers are also available.

Si7005 Driver Code

Humidity and Temperature Sensor Linux Driver Code
*The Android robot is reproduced or modified from work created and shared by Google and used according to terms described in the Creative Commons 3.0 Attribution License.

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