SNAS890A February   2025  – June 2025 HDC3120-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Device Power-Up
      2. 7.3.2 Device Disable and Enable
      3. 7.3.3 Conversion of the Signal Output
        1. 7.3.3.1 Relative Humidity (RH%) Measurement
        2. 7.3.3.2 Temperature Measurement
      4. 7.3.4 NIST Traceability and Unique ID
      5. 7.3.5 Output Short Circuit Protection
    4. 7.4 Device Functional Modes
      1. 7.4.1 On-Chip Heater
        1. 7.4.1.1 Operating Principle
          1. 7.4.1.1.1 Heater Configuration Example
        2. 7.4.1.2 Heater Electrical Behavior
        3. 7.4.1.3 Heater Temperature Increase
        4. 7.4.1.4 Heater Usage Guidelines
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
    5. 8.5 Storage and PCB Assembly
      1. 8.5.1 Storage and Handling
      2. 8.5.2 Product Storage
      3. 8.5.3 PCB Assembly Flow
      4. 8.5.4 Rework Consideration
      5. 8.5.5 Sensitivity to Chemicals and Vapors
      6. 8.5.6 Exposure to High Temperature and High Humidity Conditions
      7. 8.5.7 Recovering Sensor Performance: Bake and Rehydration Procedure
  10. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Related Documentation
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

8.2.1 Design Requirements

The accuracy of a RH and temperature measurement depends on the sensor accuracy and the setup of the sensing system. The HDC3120-Q1 senses relative humidity and temperature in the immediate environment, therefore matching the local conditions at the sensor to the monitored environment is important. Use one or more openings in the physical cover of the end product to obtain a good airflow even in static conditions. Refer to the PCB layout example which minimizes the thermal mass of the PCB in the region of the HDC3120-Q1, which can improve measurement response time and accuracy.

When designing with HDC3120-Q1, the following:

  1. To correctly sense the ambient temperature and humidity, the HDC3120-Q1 must be positioned away from heat sources on the PCB.
  2. Avoid condensing environments. Water condensation on the sensor surface can create inaccurate RH measurements. Furthermore, operation in such environments introduces a risk of water penetration under the package of the device, leading to potential short circuits between pins.
  3. Avoid direct light to the sensor. Light can accelerate capacitor polymer aging and lead to increased RH drift over time. Direct light exposure can also lead to heating of the sensor, causing inaccurate measurements.
  4. In enclosed applications, avoid placing the sensor in air "dead zones", where air flow is poor does not circulate the desired air to be measured. Sensors placed in a vertical mounting position relative to the ground yield better results than those in horizontal positions.

  5. Avoid placing sensor in strong air flow areas (wind speeds above 1m/s), as this leads to increased Temperature and RH output noise.

  6. Verify that the sensor temperature closely matches the ambient air temperature. In some cases, sensor temperature offset by 1°C can lead to 3% change of RH output error due to this mismatch.

  7. Prevent dust from accumulating over time around or on top of the sensor. For dust-ridden or dirty environments, consider the digital HDC3022, which includes an IP67 rated filer. Sensors placed in a vertical mounting position yield more positive results than those in horizontal positions to minimize dust accumulation.
  8. As the device produces ratiometric output, any noise coupled to the supply or ground voltages has an effect on the output of the device. As such, verify stable ground and supply are supplied to the device for best performance.