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

Design Requirements

To improve measurement accuracy, TI recommends to isolate the HDC302x from all heat sources in the form of active circuitry, batteries, displays and resistive elements. If design space is a constraint, cutouts surrounding the device or the inclusion of small trenches can help minimize heat transfer from PCB heat sources to the HDC302x. To avoid self-heating the HDC302x, TI recommends to configure the device to no faster than 1 measurement/second.

The HDC302x operates only as a target device and communicates with the host through the I2C-compatible serial interface. SCL is an input pin, SDA is a bidirectional pin, and ALERT is an output. The HDC302x requires a pullup resistor on the SDA. An SCL pullup resistor is required if the system microprocessor SCL pin is open-drain. The recommended value for the pullup resistors is 5 kΩ. In some applications, the pullup resistor can be lower or higher than 5 kΩ. A 0.1-µF bypass capacitor is recommended to be connected between V+ and GND. Use a ceramic capacitor type with a temperature rating that matches the operating range of the application, and place the capacitor as close as possible to the VDD pin of the HDC302x. The ADDR and ADDR0 pins should be connected directly to GND, VDD, or left open for address selection of four possible unique target ID addresses per the addressing scheme Table 8-2. The ALERT output pin can be connected to a microcontroller interrupt that triggers an event that occurred when the relative humidity and/or temperature limit exceeds the programmed value. The ALERT pin should be left floating when not in use.