SNAS778A June   2021  – September 2021 HDC3020 , HDC3021 , HDC3022

ADVANCE INFORMATION  

  1. Features
  2. Applications
  3. Description
  4. Revision History
  5. Device Comparison
  6. Pin Configuration and Functions
  7. Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Switching Characteristics
    7. 7.7 Timing Diagram
    8. 7.8 Typical Characteristics
  8. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Factory Installed Polyimide Tape
      2. 8.3.2  Factory Installed IP67 Protection Cover
      3. 8.3.3  Measurement of Relative Humidity and Temperature
      4. 8.3.4  Drift Correction: Accuracy Restoration
      5. 8.3.5  NIST Traceability of Relative Humidity and Temperature Sensor
      6. 8.3.6  Measurement Modes: Trigger-On Demand vs. Auto Measurement
      7. 8.3.7  Heater
      8. 8.3.8  ALERT Output With Programmable Interrupts
      9. 8.3.9  Checksum Calculation
      10. 8.3.10 Programmable Offset of Relative Humidity and Temperature Results
    4. 8.4 Device Functional Modes
      1. 8.4.1 Sleep Mode vs. Measurement Mode
    5. 8.5 Programming
      1. 8.5.1 I2C Interface
      2. 8.5.2 I2C Serial Bus Address Configuration
      3. 8.5.3 I2C Write - Send Device Command
      4. 8.5.4 I2C Read - Retrieve Single Data Result
      5. 8.5.5 I2C Read - Retrieve Multi Data Result
      6. 8.5.6 I2C Repeated START - Send Command and Retrieve Data Results
      7. 8.5.7 Command Table and Detailed Description
        1. 8.5.7.1 Reset
          1. 8.5.7.1.1 Soft Reset
          2. 8.5.7.1.2 I2C General Call Reset
        2. 8.5.7.2 Trigger-On Demand
        3. 8.5.7.3 Auto Measurement Mode
          1. 8.5.7.3.1 Auto Measurement Mode: Enable and Configure Measurement Interval
          2. 8.5.7.3.2 Auto Measurement Mode: Measurement Readout
          3. 8.5.7.3.3 Auto Measurement Mode: Exit
          4. 8.5.7.3.4 Auto Measurement Mode: Measurement History Readout
          5. 8.5.7.3.5 Override Default Device Power-On and Device-Reset State
        4. 8.5.7.4 ALERT Output Configuration
          1. 8.5.7.4.1 ALERT Output: Environmental Tracking of Temperature and Relative Humidity
          2. 8.5.7.4.2 ALERT Output: Representation of Environmental Thresholds and Default Threshold Values
          3. 8.5.7.4.3 ALERT Output: Steps to Calculate and Program Environmental Thresholds
          4. 8.5.7.4.4 ALERT Output: Deactivation of Environmental Tracking
          5. 8.5.7.4.5 ALERT Output: Transfer Thresholds into Non-Volatile Memory
        5. 8.5.7.5 Programmable Measurement Offset
          1. 8.5.7.5.1 Representation of Offset Value and Factory Shipped Default Value
          2. 8.5.7.5.2 Factory Shipped Default Offset Values
          3. 8.5.7.5.3 Calculate Relative Humidity Offset Value
          4. 8.5.7.5.4 Calculate Temperature Offset Value
          5. 8.5.7.5.5 Write an Offset Value
          6. 8.5.7.5.6 Verify a Programmed Offset Value
        6. 8.5.7.6 Status Register
        7. 8.5.7.7 Heater: Enable and Disable
        8. 8.5.7.8 Read NIST ID/Serial Number
  9. Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
      3. 9.2.3 Application Curve
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
    3. 11.3 Storage and PCB Assembly
      1. 11.3.1 Storage and Handling
      2. 11.3.2 Soldering Reflow
      3. 11.3.3 Rework
      4. 11.3.4 Exposure to High Temperature and High Humidity Conditions
      5. 11.3.5 Bake/Rehydration Procedure
  12. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Support Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information
    1. 13.1 Package Option Addendum
    2. 13.2 Tape and Reel Information

Package Options

Mechanical Data (Package|Pins)
  • DEF|8
Thermal pad, mechanical data (Package|Pins)
Orderable Information

Layout Guidelines

Proper PCB layout of the HDC302x is critical to obtaining accurate measurements of temperature and relative humidity. Therefore, TI recommends to:

  1. Isolate all heat sources from the HDC302x. This means positioning the HDC302x away from power intensive board components such as a battery, display, or micrcocontroller. Ideally, the only onboard component close to the HDC302x is the supply bypass capacitor. See the Section 11.2 for more information.
  2. Eliminate copper layers below the device (GND, VDD)
  3. Use slots or a cutout around the device to reduce the thermal mass and obtain a quicker response time to sudden environmental changes.
    • The diameter of the cutout around the part in this case is approximately 6 mm. The important details are to implement a separation of thermal planes while allowing for power, ground and data lines and place the part on the board, while still meeting mechanical assembly requirements. In addition to the Section 11.2, other representations of cutouts for thermal relief can be found in Optimizing Placement and Routing for Humidity Sensors section 2.3.
  4. Follow the Example Board Layout and Example Stencil Design that is illustrated in Section 13.
    • The SCL and the SDA lines require pull up resistors and TI recommends to connect a 0.1-uF cap to the VDD line.
    • TI recommends a multilayer ceramic bypass X7R capacitor of 0.1 μF between the VDD and GND pins.
  5. It is generally best practice to solder the package thermal pad to a board pad that is connected to ground, however to minimize thermal mass for maximum heater efficiency or to measure ambient temperature it may be left floating. Floating the thermal pad is an option because the thermal pad has a non-conductive epoxy. See

    HDC3x Silicon User's Guide (SNAU265)

    for more information regarding when leaving the thermal pad floating may be helpful for your application