SNOSDD0 December   2021 LDC3114

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 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 Digital Interface
    7. 6.7 I2C Interface
    8. 6.8 Timing Diagram
    9. 6.9 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Multimode Operation
      2. 7.3.2 Multichannel and Single-Channel Operation
      3. 7.3.3 Raw Data Output
      4. 7.3.4 Button Output Interfaces
      5. 7.3.5 Programmable Button Sensitivity
      6. 7.3.6 Baseline Tracking
      7. 7.3.7 Integrated Button Algorithms
      8. 7.3.8 I2C Interface
        1. 7.3.8.1 I2C Interface Specifications
        2. 7.3.8.2 I2C Bus Control
    4. 7.4 Device Functional Modes
      1. 7.4.1 Normal Power Mode
      2. 7.4.2 Low Power Mode
      3. 7.4.3 Configuration Mode
    5. 7.5 Register Maps
      1. 7.5.1 LDC3114 Registers
      2. 7.5.2 Gain Table for Registers GAIN0, GAIN1, GAIN2, and GAIN3
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1  Theory of Operation
      2. 8.1.2  Designing Sensor Parameters
      3. 8.1.3  Setting COM Pin Capacitor
      4. 8.1.4  Defining Power-On Timing
      5. 8.1.5  Configuring Button or Raw Data Scan Rate
      6. 8.1.6  Programming Button or Raw Data Sampling Window
      7. 8.1.7  Scaling Frequency Counter Output
      8. 8.1.8  Setting Button Triggering Threshold
      9. 8.1.9  Tracking Baseline
      10. 8.1.10 Mitigating False Button Detections
        1. 8.1.10.1 Eliminating Common-Mode Change (Anti-Common)
        2. 8.1.10.2 Resolving Simultaneous Button Presses (Max-Win)
        3. 8.1.10.3 Overcoming Case Twisting (Anti-Twist)
        4. 8.1.10.4 Mitigating Metal Deformation (Anti-Deform)
      11. 8.1.11 Reporting Interrupts for Button Presses, Raw Data Ready and Error Conditions
      12. 8.1.12 Estimating Supply Current
    2. 8.2 Typical Application
      1. 8.2.1 Touch Button Design
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Support Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

7.3.1 Multimode Operation

LDC3114 offers two main modes of operations: raw data access mode and button algorithm mode which is controlled by the BTN_ALG_EN field in Register INTPOL Address 0x11. Figure 7-2 shows conceptually how these two modes are implemented.

Raw data access mode allows an external MCU to extract data from the signal after the inductance-to-digital converter from registers through I2C (see Section 7.3.3). There is no further processing on this raw data such as baseline tracking, integrated button algorithms and button thresholding. This mode gives MCU full control over the measured raw data to implement algorithms for linear position sensing, rotational encoder applications, metal presence/deflection applications, smart button algorithms and for multimodal sensor fusion applications.

The second mode is button algorithm mode. Here further processing with parameters defined by the user (see Section 7.3.6 and Section 7.3.7) is done on the data and a button thresholding as defined by the user is applied. The processed data are available in separate registers to be read by I2C and any button press detection is indicated on the OUTx pins (see Section 7.3.4) This mode is used to implement button press functionality and can also be used to implement the measurement of force applied for button press along with detection to implement multilevel button press.

For register settings that are applicable to button mode versus raw access data mode are clearly identified in the descriptions of the registers (see Section 7.5).

GUID-20200926-CA0I-C5QW-V2L2-Z5J90PDS6H3W-low.gif Figure 7-2 Multimode Operation in LDC3114