JAJSEC1C November   2019  – July 2020 ADS8686S

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: Universal
    9. 6.9  Timing Diagrams: Parallel Data Read
    10. 6.10 Timing Diagrams: Serial Data Read
    11. 6.11 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  Analog Inputs
      2. 7.3.2  Analog Input Impedance
      3. 7.3.3  Input Clamp Protection Circuit
      4. 7.3.4  Programmable Gain Amplifier (PGA)
      5. 7.3.5  Second-Order, Programmable, Low-Pass Filter (LPF)
      6. 7.3.6  ADC Driver
      7. 7.3.7  Multiplexer
      8. 7.3.8  Digital Filter and Noise
      9. 7.3.9  Reference
        1. 7.3.9.1 Internal Reference
        2. 7.3.9.2 External Reference
        3. 7.3.9.3 Supplying One VREF to Multiple Devices
      10. 7.3.10 ADC Transfer Function
    4. 7.4 Device Functional Modes
      1. 7.4.1 Device Interface: Pin Description
        1. 7.4.1.1  REFSEL (Input)
        2. 7.4.1.2  RESET (Input)
        3. 7.4.1.3  SEQEN (Input)
        4. 7.4.1.4  HW_RANGESEL[1:0] (Input)
        5. 7.4.1.5  SER/BYTE/PAR (Input)
        6. 7.4.1.6  DB[3:0] (Input/Output)
        7. 7.4.1.7  DB4/SER1W (Input/Output)
        8. 7.4.1.8  DB5/CRCEN (Input/Output)
        9. 7.4.1.9  DB[7:6] (Input/Output)
        10. 7.4.1.10 DB8 (Input/Output)
        11. 7.4.1.11 DB9/BYTESEL (Input/Output)
        12. 7.4.1.12 DB10/SDI (Input/Output)
        13. 7.4.1.13 DB11/SDOB (Input/Output)
        14. 7.4.1.14 DB12/SDOA (Input/Output)
        15. 7.4.1.15 DB13/OS0 (Input/Output)
        16. 7.4.1.16 DB14/OS1 (Input/Output)
        17. 7.4.1.17 DB15/OS2 (Input/Output)
        18. 7.4.1.18 WR/BURST (Input)
        19. 7.4.1.19 SCLK/RD (Input)
        20. 7.4.1.20 CS (Input)
        21. 7.4.1.21 CHSEL[2:0] (Input)
        22. 7.4.1.22 BUSY (Output)
        23. 7.4.1.23 CONVST (Input)
      2. 7.4.2 Device Modes of Operation
        1. 7.4.2.1 Shutdown Mode
        2. 7.4.2.2 Operation Mode
          1. 7.4.2.2.1 Hardware Mode
          2. 7.4.2.2.2 Software Mode
        3. 7.4.2.3 Reset Functionality
        4. 7.4.2.4 Channel Selection
          1. 7.4.2.4.1 Hardware Mode Channel Selection
          2. 7.4.2.4.2 Software Mode Channel Selection
        5. 7.4.2.5 Sequencer
          1. 7.4.2.5.1 Hardware Mode Sequencer
          2. 7.4.2.5.2 Software Mode Sequencer
        6. 7.4.2.6 Burst Sequencer
          1. 7.4.2.6.1 Hardware Mode Burst Sequencer
          2. 7.4.2.6.2 Software Mode Burst Sequencer
        7. 7.4.2.7 Diagnostics
          1. 7.4.2.7.1 Analog Diagnosis
          2. 7.4.2.7.2 Interface Diagnosis: SELF TEST and CRC
    5. 7.5 Programming
      1. 7.5.1 Parallel Interface
        1. 7.5.1.1 Reading Conversion Results
        2. 7.5.1.2 Writing Register Data
        3. 7.5.1.3 Reading Register Data
      2. 7.5.2 Parallel Byte Interface
        1. 7.5.2.1 Reading Conversion Results
        2. 7.5.2.2 Writing Register Data
        3. 7.5.2.3 Reading Register Data
      3. 7.5.3 Serial Interface
        1. 7.5.3.1 Reading Conversion Results
        2. 7.5.3.2 Writing Register Data
        3. 7.5.3.3 Reading Register Data
    6. 7.6 Register Maps
      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 8x2 Channel Data Acquisition System (DAQ) for Power Automation
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curve
      2. 8.2.2 Input Protection for Electrical Overstress
  9. 9 Power Supply Recommendations
    1. 9.1 Power Supplies
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Examples
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Development Support
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 サポート・リソース
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary

7.5.3.1 Reading Conversion Results

A channel conversion is initiated when the CONVST signal transitions from low to high. The BUSY signal goes high and stays high to indicate an ongoing conversion. A data read cycle can be initiated after the BUSY signal goes low, indicating that the conversion is complete.

The CS falling edge takes the data output lines, SDOA and SDOB, out of tri-state and clocks out the MSB of the conversion result. The rising edge of SCLK clocks all subsequent data bits onto the serial data outputs, SDOA and SDOB. Figure 7-29 illustrates a read of two simultaneous conversion results using two SDOx lines on the ADS8686S. If the status register is appended to the conversion results or operates in sequencer burst mode where multiples of 16 SCLK transfers access data from the ADS8686S, hold CS low for the entire data frame. Data can also be clocked out using just the SDOA line. For the ADS8686S to access both the channel AIN_xA and channel AIN_xB conversion results on the SDOA line, a total of 32 SCLK cycles is required. Frame these 32 SCLK cycles using one CS signal, or individually frame each group of 16 SCLK cycles using the CS signal. The disadvantage of using just serial 1-wire mode is that the throughput rate is reduced.

Leave the unused SDOB line unconnected in serial 1-wire mode. If using SDOA as a single serial data output line, the channel results are output in the following order: AIN_xA and AIN_xB. Figure 7-30 shows a 1-wire, serial readback operation.

The speed at which the data can be read back in serial interface mode is dependent on the SPI frequency, DVDD supply, and the capacitance of the load on the SDO line, CLOAD. Table 7-10 shows a summary of the maximum speed achievable for various conditions.

Table 7-10 SPI Frequency versus Load Capacitance and DVDD
DVDD (V)CLOAD (pF)SPI FREQUENCY (MHz)
1.8 to 32040
3 to 53050
GUID-3D6EC4B8-9A49-4A6D-BD1D-B159D5C2F14D-low.gifFigure 7-29 Serial Interface, 2-Wire Mode
GUID-3D5C21FB-31EA-41A2-8564-268C292B0B33-low.gifFigure 7-30 Serial Interface, 1-Wire Mode