[FAQ] HDC2080/HDC2010 - What are the key specifications for TI humidity sensors?

Relative Humidity accuracy: It is valid for the range from 20% RH to 80% RH under non condensing conditions and for temperature ranges from 0 to 60°C. This specification excludes any effect of contaminants as described in the application note Humidity Sensor: Storage and Handling Guidelines. Please note: TI’s maximum specifications do include the effects of humidity hysteresis; many other polymer based humidity sensors do not include hysteresis in their accuracy specification.

Temperature Accuracy: Each device in the HDC family of parts has an integrated temperature sensor which is factory-calibrated to the accuracy levels listed in device specific datasheets.

Resolution: The HDC family of devices has configurable measurement resolutions available for both temperature and humidity. By choosing a lower measurement resolution, the active conversion time of the HDC is also reduced. This can be used to optimize for ultra-low power applications, when the least significant bits (LSBs) of resolution are not required for system performance.

Power Consumption: Power consumption for the HDC family of devices is primarily dependent on the Vin Range, Conversion Time, Conversion Rate, and Active/Standby Current values. Each is described in more detail below. 

• Vin Range: Each device (and all ICs) has a specific supply voltage range, for the HDC devices this is no different. The Absolute Maximum range is the maximum condition that can be applied without IC damage. The Recommended Operatingrange is what range the device should be in under normal circumstances. The supply voltage is also often a test condition for the specifications found in the Electrical Characteristics (EC) table of the datasheet.

• Conversion Time: The conversion time is the amount of time it takes for the device to complete a temperature conversion. During the conversion time, the sensor ADC is active and consuming power, which increases the device current consumption.
• Conversion Rate: The conversion rate is how often a conversion is performed. When conversions are manually triggered, this is controlled by the MCU or host that is commanding the sensor to convert. When properly configured, the HDC20xx family of parts can also self-trigger conversions at regular intervals.
• Active/Standby Current: The active current is the current consumed while the device ADC is active, and a conversion is being performed. The standby current is the current drawn when the device is waiting between conversions.

To help illustrate the concepts above – below are current meter captures of 9, 11 and 14 bit temperature and humidity conversions over the conversion time(s) needed for each resolution. These examples are taken with HDC20x0.

9 Bit Conversion	11 Bit Conversion	14 Bit Conversion

Package Type/Dimensions: Polymer based humidity sensors typically include an opening in the package where the sensing polymer sits. The HDC Family of sensors are available in both surface mount DFN packages, where the sensing element is on top of the IC package, and WCSP packages where the sensing element is underneath the device. WCSP packages (HDCx010 devices) at smaller and preferable for space constrained applications.