SBAS891B November   2017  – September 2022 ADS7142-Q1

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: All Modes
    6. 6.6  Electrical Characteristics: Manual Mode
    7. 6.7  Electrical Characteristics: Autonomous Modes
    8. 6.8  Electrical Characteristics: High Precision Mode
    9. 6.9  Timing Requirements
    10. 6.10 Switching Characteristics
    11. 6.11 Timing Diagrams
    12. 6.12 Typical Characteristics: All Modes
    13. 6.13 Typical Characteristics: Manual Mode
    14. 6.14 Typical Characteristics: Autonomous Modes
    15. 6.15 Typical Characteristics: High-Precision Mode
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Analog Input and Multiplexer
        1. 7.3.1.1 Two-Channel, Single-Ended Configuration
        2. 7.3.1.2 Single-Channel, Single-Ended Configuration With Remote Ground Sense
        3. 7.3.1.3 Single-Channel, Pseudo-Differential Configuration
      2. 7.3.2  Offset Calibration
      3. 7.3.3  Reference
      4. 7.3.4  ADC Transfer Function
      5. 7.3.5  Oscillator and Timing Control
      6. 7.3.6  I2C Address Selector
      7. 7.3.7  Data Buffer
        1. 7.3.7.1 Filling of the Data Buffer
        2. 7.3.7.2 Reading Data From the Data Buffer
      8. 7.3.8  Accumulator
      9. 7.3.9  Digital Window Comparator
      10. 7.3.10 I2C Protocol Features
        1. 7.3.10.1 General Call
        2. 7.3.10.2 General Call With Software Reset
        3. 7.3.10.3 General Call With Write Software Programmable Part of the Target Address
        4. 7.3.10.4 Configuring the ADC Into High-Speed I2C Mode
        5. 7.3.10.5 Bus Clear
    4. 7.4 Device Functional Modes
      1. 7.4.1 Device Power Up and Reset
      2. 7.4.2 Manual Mode
        1. 7.4.2.1 Manual Mode With CH0 Only
        2. 7.4.2.2 Manual Mode With AUTO Sequence
      3. 7.4.3 Autonomous Modes
        1. 7.4.3.1 Autonomous Mode With Threshold Monitoring and Diagnostics
          1. 7.4.3.1.1 Autonomous Mode With Pre-ALERT Data
          2. 7.4.3.1.2 Autonomous Mode With Post-ALERT Data
        2. 7.4.3.2 Autonomous Mode With Burst Data
          1. 7.4.3.2.1 Autonomous Mode With Start Burst
          2. 7.4.3.2.2 Autonomous Mode With Stop Burst
      4. 7.4.4 High-Precision Mode
    5. 7.5 Programming
      1. 7.5.1 Reading Registers
        1. 7.5.1.1 Single Register Read
        2. 7.5.1.2 Reading a Continuous Block of Registers
      2. 7.5.2 Writing Registers
        1. 7.5.2.1 Single Register Write
        2. 7.5.2.2 Writing a Continuous Block of Registers
        3. 7.5.2.3 Set Bit
        4. 7.5.2.4 Clear Bit
    6. 7.6 Register Map
      1. 7.6.1 Page1 Registers
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 ADS7142-Q1 as a Programmable Comparator With False Trigger Prevention and Diagnostics
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Programmable Thresholds and Hysteresis
          2. 8.2.1.2.2 False Trigger Prevention With an Event Counter
          3. 8.2.1.2.3 Fault Diagnostics With the Data Buffer
        3. 8.2.1.3 Application Curves
      2. 8.2.2 Voltage and Temperature Monitoring in Remote Camera Modules Using the ADS7142-Q1
        1. 8.2.2.1 Design Requirements
    3. 8.3 Power Supply Recommendations
      1. 8.3.1 AVDD and DVDD Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  9. 9 Device and Documentation Support
    1. 9.1 Electrostatic Discharge Caution
    2. 9.2 Glossary
    3. 9.3 Trademarks
    4. 9.4 Receiving Notification of Documentation Updates
    5. 9.5 Support Resources
  10. 10Mechanical, Packaging, and Orderable Information

8.2.2.1 Design Requirements

Camera modules are an integral part of advanced driver assistance systems (ADAS), which are designed to make cars safer. Automotive cameras and camera modules are often assist in blind spot detection, nap prevention, lane and border detection, surround view and parking. Based on application, there are multiple types of camera modules available such as front camera, rear camera, night vision camera. Figure 8-8 shows the typical block diagram of camera module used in an automotive environment with key electronics building blocks in the system.

The camera module is usually situated externally at front, back or either side of the vehicle. Many times the main controller that does the data processing can not be used on camera module side due to size constraints. The camera module unit communicates with central processor over co-axial cable. The camera module data is transmitted over a coaxial cable using a serializer. On the data processing unit, a deserializer is used to communicate this data with the host processor. The power to the camera module is also transmitted over a coaxial cable. Because the camera module is remotely placed and power is transferred over a coaxial cable that can be few meters long, voltage received by camera module and critical voltage rails powering image sensors are often monitored against permissible variations. Also, the difference between camera lens and external ambient temperature can introduce dampness and degrade video quality. To ensure optimal video quality, camera lens temperature is often monitored for any possible correction. The device monitoring these system-level parameters must be a small size because of the limited board space available on the camera module side. Also, the I2C interface is preferred because this interface enables the user to connect multiple monitoring and sensing devices on the same I2C bus. The ADS7142-Q1 small footprint (2-mm × 3-mm, WSON package) and the I2C interface capable of working over wide digital I/O voltages enable this device in camera module monitoring applications without demanding extra board space.