SBAS590E March   2016  – June 2020 ADS131A02 , ADS131A04

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Simplified Block Diagram
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
    1.     Pin Functions
  7. 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  Timing Requirements: Asynchronous Interrupt Interface Mode
    7. 7.7  Switching Characteristics: Asynchronous Interrupt Interface Mode
    8. 7.8  Timing Requirements: Synchronous Master Interface Mode
    9. 7.9  Switching Characteristics: Synchronous Master Interface Mode
    10. 7.10 Timing Requirements: Synchronous Slave Interface Mode
    11. 7.11 Switching Characteristics: Synchronous Slave Interface Mode
    12. 7.12 Typical Characteristics
  8. 8 Parameter Measurement Information
    1. 8.1 Noise Measurements
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Clock
        1. 9.3.1.1 XTAL1/CLKIN and XTAL2
        2. 9.3.1.2 ICLK
        3. 9.3.1.3 MODCLK
        4. 9.3.1.4 Data Rate
      2. 9.3.2 Analog Input
      3. 9.3.3 Input Overrange and Underrange Detection
      4. 9.3.4 Reference
      5. 9.3.5 ΔΣ Modulator
      6. 9.3.6 Digital Decimation Filter
      7. 9.3.7 Watchdog Timer
    4. 9.4 Device Functional Modes
      1. 9.4.1 Low-Power and High-Resolution Mode
      2. 9.4.2 Power-Up
      3. 9.4.3 Standby and Wake-Up Mode
      4. 9.4.4 Conversion Mode
      5. 9.4.5 Reset (RESET)
    5. 9.5 Programming
      1. 9.5.1 Interface Protocol
        1. 9.5.1.1 Device Word Length
        2. 9.5.1.2 Fixed versus Dynamic-Frame Mode
        3. 9.5.1.3 Command Word
        4. 9.5.1.4 Status Word
        5. 9.5.1.5 Data Words
          1. 9.5.1.5.1 ADC Data Word 16-Bit Format
          2. 9.5.1.5.2 ADC Data Word 24-Bit Format
        6. 9.5.1.6 Hamming Code Error Correction
        7. 9.5.1.7 Cyclic Redundancy Check (CRC)
          1. 9.5.1.7.1 Computing the CRC
          2. 9.5.1.7.2 CRC With CRC_MODE = 1
          3. 9.5.1.7.3 CRC with CRC_MODE = 0
          4. 9.5.1.7.4 CRC Using the WREGS Command
      2. 9.5.2 SPI Interface
        1. 9.5.2.1 Asynchronous Interrupt Mode
          1. 9.5.2.1.1 Chip Select (CS)
          2. 9.5.2.1.2 Serial Clock (SCLK)
          3. 9.5.2.1.3 Data Input (DIN)
          4. 9.5.2.1.4 Data Output (DOUT)
          5. 9.5.2.1.5 Data Ready (DRDY)
          6. 9.5.2.1.6 Asynchronous Interrupt Mode Data Retrieval
        2. 9.5.2.2 Synchronous Master Mode
          1. 9.5.2.2.1 Serial Clock (SCLK)
          2. 9.5.2.2.2 Data Input (DIN)
          3. 9.5.2.2.3 Data Output (DOUT)
          4. 9.5.2.2.4 Data Ready (DRDY)
          5. 9.5.2.2.5 Chip Select (CS)
          6. 9.5.2.2.6 Synchronous Master Mode Data Retrieval
        3. 9.5.2.3 Synchronous Slave Mode
          1. 9.5.2.3.1 Chip Select (CS)
          2. 9.5.2.3.2 Serial Clock (SCLK)
          3. 9.5.2.3.3 Data Input (DIN)
          4. 9.5.2.3.4 Data Output (DOUT)
          5. 9.5.2.3.5 Data Ready (DRDY)
          6. 9.5.2.3.6 Synchronous Slave Mode Data Retrieval
        4. 9.5.2.4 ADC Frame Complete (DONE)
      3. 9.5.3 SPI Command Definitions
        1. 9.5.3.1  NULL: Null Command
        2. 9.5.3.2  RESET: Reset to POR Values
        3. 9.5.3.3  STANDBY: Enter Standby Mode
        4. 9.5.3.4  WAKEUP: Exit Standby Mode
        5. 9.5.3.5  LOCK: Lock ADC Registers
        6. 9.5.3.6  UNLOCK: Unlock ADC Registers
          1. 9.5.3.6.1 UNLOCK from POR or RESET
        7. 9.5.3.7  RREG: Read a Single Register
        8. 9.5.3.8  RREGS: Read Multiple Registers
        9. 9.5.3.9  WREG: Write Single Register
        10. 9.5.3.10 WREGS: Write Multiple Registers
    6. 9.6 Register Maps
      1. 9.6.1 User Register Description
        1. 9.6.1.1  ID_MSB: ID Control Register MSB (address = 00h) [reset = xxh]
          1. Table 16. ID_MSB Register Field Descriptions
        2. 9.6.1.2  ID_LSB: ID Control Register LSB (address = 01h) [reset = xxh]
          1. Table 17. ID_LSB Register Field Descriptions
        3. 9.6.1.3  STAT_1: Status 1 Register (address = 02h) [reset = 00h]
          1. Table 18. STAT_1 Register Field Descriptions
        4. 9.6.1.4  STAT_P: Positive Input Fault Detect Status Register (address = 03h) [reset = 00h]
          1. Table 19. STAT_P Register Field Descriptions
        5. 9.6.1.5  STAT_N: Negative Input Fault Detect Status Register (address = 04h) [reset = 00h]
          1. Table 20. STAT_N Register Field Descriptions
        6. 9.6.1.6  STAT_S: SPI Status Register (address = 05h) [reset = 00h]
          1. Table 21. STAT_S Register Field Descriptions
        7. 9.6.1.7  ERROR_CNT: Error Count Register (address = 06h) [reset = 00h]
          1. Table 22. ERROR_CNT Register Field Descriptions
        8. 9.6.1.8  STAT_M2: Hardware Mode Pin Status Register (address = 07h) [reset = xxh]
          1. Table 23. STAT_M2 Register Field Descriptions
        9. 9.6.1.9  Reserved Registers (address = 08h to 0Ah) [reset = 00h]
          1. Table 24. Reserved Registers Field Descriptions
        10. 9.6.1.10 A_SYS_CFG: Analog System Configuration Register (address = 0Bh) [reset = 60h]
          1. Table 25. A_SYS_CFG Register Field Descriptions
        11. 9.6.1.11 D_SYS_CFG: Digital System Configuration Register (address = 0Ch) [reset = 3Ch]
          1. Table 27. D_SYS_CFG Register Field Descriptions
        12. 9.6.1.12 CLK1: Clock Configuration 1 Register (address = 0Dh) [reset = 08h]
          1. Table 28. CLK1 Register Field Descriptions
        13. 9.6.1.13 CLK2: Clock Configuration 2 Register (address = 0Eh) [reset = 86h]
          1. Table 29. CLK2 Register Field Descriptions
        14. 9.6.1.14 ADC_ENA: ADC Channel Enable Register (address = 0Fh) [reset = 00h]
          1. Table 31. ADC_ENA Register Field Descriptions
        15. 9.6.1.15 Reserved Register (address = 10h) [reset = 00h]
          1. Table 32. Reserved Register Field Descriptions
      2. 9.6.2 ADCx: ADC Channel Digital Gain Configuration Registers (address = 11h to 14h) [reset = 00h]
        1. Table 33. ADCx Registers Field Descriptions
  10. 10Application and Implementation
    1. 10.1 Application Information
      1. 10.1.1 Unused Inputs and Outputs
      2. 10.1.2 Power Monitoring Specific Applications
      3. 10.1.3 Multiple Device Configuration
        1. 10.1.3.1 First Device Configured in Asynchronous Interrupt Mode
        2. 10.1.3.2 First Device Configured in Synchronous Master Mode
        3. 10.1.3.3 All Devices Configured in Synchronous Slave Mode
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
      3. 10.2.3 Application Curve
    3. 10.3 What To Do and What Not To Do
    4. 10.4 Initialization Set Up
  11. 11Power Supply Recommendations
    1. 11.1 Negative Charge Pump
    2. 11.2 Internal Digital LDO
    3. 11.3 Power-Supply Sequencing
    4. 11.4 Power-Supply Decoupling
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
  13. 13Device and Documentation Support
    1. 13.1 Documentation Support
      1. 13.1.1 Related Documentation
    2. 13.2 Related Links
    3. 13.3 Receiving Notification of Documentation Updates
    4. 13.4 Support Resources
    5. 13.5 Trademarks
    6. 13.6 Electrostatic Discharge Caution
    7. 13.7 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

パッケージ・オプション

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発注情報

9.3.1 Clock

Multiple clocks are created from one external master clock source in the ADS131A0x to create device configuration flexibility. The ADC operates from the internal system clock, ICLK, which is provided in one of three ways.

  • An external master clock, CLKIN, can be applied directly to the XTAL1/CLKIN pin to be divided down to generate ICLK using the CLK_DIV[2:0] bits in the CLK1 register. In this case, leave the XTAL2 pin floating.
  • A crystal oscillator can be applied between XTAL1/CLKIN and XTAL2, generating a master clock to be divided down using the CLK_DIV[2:0] bits in the CLK1 register to generate ICLK.
  • A free-running SCLK can be internally routed to be set as ICLK. This mode is only available in synchronous slave interface mode. Tie the CLKIN/XTAL1 pin to GND. Leave the XTAL2 pin unconnected.

The system ICLK is passed through a second 3-bit clock divider (ICLK_DIV[2:0] in the CLK2 register) to create the modulator clock, MODCLK. MODCLK is used for timing of the delta-sigma (ΔΣ) modulator sampling and digital filter.

The interface operation mode determines the options for sourcing ICLK. When in asynchronous interrupt or synchronous master mode, generate ICLK by applying a direct external master clock signal to the XTAL1/CLKIN pin or by using a crystal oscillator across the XTAL1/CLKIN and XTAL2 pins. If directly applying a master clock to the XTAL1/CLKIN pin, leave XTAL2 floating. In synchronous slave mode, a free-running SCLK line can be connected directly into the ICLK_DIV block in place of the divided XTAL or CLKIN source. Use the CLKSRC bit in the CLK1 register to select between the XTAL1/CLKIN or SCLK input as the master clock source for the ADC. The CLKSRC bit must be set prior to powering up the ADC channels. Using SCLK as ICLK is useful in galvanic isolated applications to limit the digital I/O lines crossing the isolation barrier. Figure 35 shows the clock dividers and clocking names.

ADS131A02 ADS131A04 ADC_Clock_Generation_sbas590.gifFigure 35. ADC Clock Generation