SNOSCZ4A April   2015  – October 2024 FDC1004-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 I2C Interface Voltage Level
    7. 5.7 I2C Interface Timing
    8. 5.8 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 The Shield
      2. 6.3.2 The CAPDAC
      3. 6.3.3 Capacitive System Offset Calibration
      4. 6.3.4 Capacitive Gain Calibration
    4. 6.4 Device Functional Modes
      1. 6.4.1 Single Ended Measurement
      2. 6.4.2 Differential Measurement
    5. 6.5 Programming
      1. 6.5.1 Serial Bus Address
      2. 6.5.2 Read/Write Operations
      3. 6.5.3 Device Usage
        1. 6.5.3.1 Measurement Configuration
        2. 6.5.3.2 Triggering Measurements
        3. 6.5.3.3 Wait for Measurement Completion
        4. 6.5.3.4 Read of Measurement Result
    6. 6.6 Register Maps
      1. 6.6.1 Registers
        1. 6.6.1.1 Capacitive Measurement Registers
      2. 6.6.2 Measurement Registers
      3. 6.6.3 Measurement Configuration Registers
      4. 6.6.4 FDC Configuration Register
      5. 6.6.5 Offset Calibration Registers
      6. 6.6.6 Gain Calibration Registers
      7. 6.6.7 Manufacturer ID Register
      8. 6.6.8 Device ID Register
  8. 7 Applications and Implementation
    1. 7.1 Application Information
      1. 7.1.1 Liquid Level Sensor
    2. 7.2 Typical Application
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
      3. 7.2.3 Application Curve
    3. 7.3 Best Design Practices
    4. 7.4 Initialization Set Up
    5. 7.5 Power Supply Recommendations
    6. 7.6 Layout
      1. 7.6.1 Layout Guidelines
      2. 7.6.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Documentation Support
      1. 8.1.1 Related Documentation
    2. 8.2 Receiving Notification of Documentation Updates
    3. 8.3 Support Resources
    4. 8.4 Trademarks
    5. 8.5 Electrostatic Discharge Caution
    6. 8.6 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

6.5.3.1 Measurement Configuration

Configuring a measurement involves setting the input channels and the type of measurement (single-ended or differential).

The FDC1004-Q1 can be configured with up to 4 separate measurements, where each measurement can be any valid configuration (that is, a specific channel can be used in multiple measurements). There is a dedicated configuration register for each of the 4 possible measurements (for example, MEAS_CONF1 in register 0x08 configures measurement 1, MEAS_CONF2 in register 0x09 configures measurement 2, ...). Configuring only one measurement is allowed, and it can be one of the 4 possible measurement configurations.

  1. Set up the input channels for each measurement. Determine which of the 4 measurement configuration registers to use (registers 0x08 to 0x0A) and set the following:
    1. For single-ended measurement:
      1. Select the positive input pin for the measurement by setting the CHA field (bits[15:13]).
      2. Set CAPDAC (bits[9:5]) if the channel offset capacitance is more than 15pF.
    2. For a differential measurement:
      1. Select the positive input pin for the measurement by setting the CHA field (bits[15:13]).
      2. Select the negative input pin for the measurement by setting the CHB field (bits[12:10]). Note that the CAPDAC setting has no effect for a differential measurement.
  2. Determine the appropriate sample rate. The sample rate sets the resolution of the measurement. Lower the sample rate higher is the resolution of the measurement.