JAJSKF2B November   2020  – November 2021 ADS131B04-Q1

PRODUCTION DATA  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
  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 Timing Requirements
    7. 6.7 Switching Characteristics
    8. 6.8 Timing Diagrams
    9. 6.9 Typical Characteristics
  7. 7 Parameter Measurement Information
    1. 7.1 Noise Measurements
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Input ESD Protection Circuitry
      2. 8.3.2  Input Multiplexer
      3. 8.3.3  Programmable Gain Amplifier (PGA)
      4. 8.3.4  Voltage Reference
      5. 8.3.5  Internal Test Signals
      6. 8.3.6  Clocking
        1. 8.3.6.1 External Clock Using CLKIN Pin
        2. 8.3.6.2 Internal Oscillator
      7. 8.3.7  ΔΣ Modulator
      8. 8.3.8  Digital Filter
        1. 8.3.8.1 Digital Filter Implementation
          1. 8.3.8.1.1 Fast-Settling Filter
          2. 8.3.8.1.2 SINC3 and SINC3 + SINC1 Filter
        2. 8.3.8.2 Digital Filter Characteristic
      9. 8.3.9  Calibration Registers
      10. 8.3.10 Register Map CRC
    4. 8.4 Device Functional Modes
      1. 8.4.1 Power-Up and Reset
        1. 8.4.1.1 Power-On Reset
        2. 8.4.1.2 SYNC/RESET Pin
        3. 8.4.1.3 RESET Command
      2. 8.4.2 Fast Start-Up Behavior
      3. 8.4.3 Conversion Modes
        1. 8.4.3.1 Continuous-Conversion Mode
        2. 8.4.3.2 Global-Chop Mode
      4. 8.4.4 Power Modes
      5. 8.4.5 Standby Mode
      6. 8.4.6 Synchronization
    5. 8.5 Programming
      1. 8.5.1 Serial Interface
        1. 8.5.1.1  Chip Select (CS)
        2. 8.5.1.2  Serial Data Clock (SCLK)
        3. 8.5.1.3  Serial Data Input (DIN)
        4. 8.5.1.4  Serial Data Output (DOUT)
        5. 8.5.1.5  Data Ready (DRDY)
        6. 8.5.1.6  SPI Communication Frames
        7. 8.5.1.7  SPI Communication Words
        8. 8.5.1.8  Short SPI Frames
        9. 8.5.1.9  Communication Cyclic Redundancy Check (CRC)
        10. 8.5.1.10 SPI Timeout
      2. 8.5.2 ADC Conversion Data Format
      3. 8.5.3 Commands
        1. 8.5.3.1 NULL (0000 0000 0000 0000)
        2. 8.5.3.2 RESET (0000 0000 0001 0001)
        3. 8.5.3.3 STANDBY (0000 0000 0010 0010)
        4. 8.5.3.4 WAKEUP (0000 0000 0011 0011)
        5. 8.5.3.5 LOCK (0000 0101 0101 0101)
        6. 8.5.3.6 UNLOCK (0000 0110 0110 0110)
        7. 8.5.3.7 RREG (101a aaaa annn nnnn)
          1. 8.5.3.7.1 Reading a Single Register
          2. 8.5.3.7.2 Reading Multiple Registers
        8. 8.5.3.8 WREG (011a aaaa annn nnnn)
      4. 8.5.4 Collecting Data for the First Time or After a Pause in Data Collection
    6. 8.6 Register Map
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Troubleshooting
      2. 9.1.2 Unused Inputs and Outputs
      3. 9.1.3 Antialias Filter
      4. 9.1.4 Minimum Interface Connections
      5. 9.1.5 Multiple Device Configuration
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Current Shunt Measurement
        2. 9.2.2.2 Battery Pack Voltage Measurement
        3. 9.2.2.3 Shunt Temperature Measurement
        4. 9.2.2.4 Auxiliary Analog Supply Voltage Measurement
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
    1. 10.1 CAP Pin Capacitor Requirement
    2. 10.2 Power-Supply Sequencing
    3. 10.3 Power-Supply Decoupling
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  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 サポート・リソース
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

8.5.1.9 Communication Cyclic Redundancy Check (CRC)

The ADS131B04-Q1 features a cyclic redundancy check (CRC) engine on both input and output data to mitigate SPI communication errors. The CRC word is 16 bits wide for either input or output CRC. Coverage includes all words in the SPI frame where the CRC is enabled, including zero-padded or sign-extended bits.

CRC on the SPI input is optional and can be enabled and disabled by writing the RX_CRC_EN bit in the MODE register. Input CRC is disabled by default. When the input CRC is enabled, the device checks the provided input CRC against the CRC generated based on the input data. A CRC error occurs if the CRC words do not match. The device does not execute any commands, except for the WREG command, if the input CRC check fails. A WREG command always executes even when the CRC check fails. The device sets the CRC_ERR bit in the STATUS register for all cases of a CRC error. The response on the output in the SPI frame following the frame where the CRC error occurred is that of a NULL command, which means the STATUS register plus the conversion data are output in the following SPI frame. The CRC_ERR bit is cleared when the STATUS register is output.

The output CRC cannot be disabled and always appears at the end of the output frame. The host can ignore the data if the output CRC is not used.

There are two types of CRC polynomials available: CCITT CRC and ANSI CRC (CRC-16). The CRC setting determines the algorithm for both the input and output CRC. The CRC type is programmed by the CRC_TYPE bit in the MODE register. Table 8-8 lists the details of the two CRC types. The CRC calculation is initialized with the seed value of FFFFh to detect errors in the event that DIN or DOUT are stuck low.

Table 8-8 CRC Types
CRC TYPE POLYNOMIAL BINARY POLYNOMIAL
CCITT CRC x16 + x12 + x5 + 1 0001 0000 0010 0001
ANSI CRC x16 + x15 + x2 + 1 1000 0000 0000 0101