SBAS876C August   2018  – June 2019 ADS9224R , ADS9234R

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Typical Application Diagram
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin 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: ADS92x4R
    6. 6.6  Electrical Characteristics: ADS9224R
    7. 6.7  Electrical Characteristics: ADS9234R
    8. 6.8  Timing Requirements
    9. 6.9  Switching Characteristics
    10. 6.10 Typical Characteristics: ADS9224R
    11. 6.11 Typical Characteristics: ADS9234R
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Converter Modules
        1. 7.3.1.1 Analog Input With Sample-and-Hold
        2. 7.3.1.2 ADC Transfer Function
      2. 7.3.2 Internal Reference Voltage
      3. 7.3.3 Reference Buffers
      4. 7.3.4 REFby2 Buffer
      5. 7.3.5 Data Averaging
        1. 7.3.5.1 Averaging of Two Samples
        2. 7.3.5.2 Averaging of Four Samples
    4. 7.4 Device Functional Modes
      1. 7.4.1 ACQ State
      2. 7.4.2 CNV State
      3. 7.4.3 Reset or Power-Down
        1. 7.4.3.1 Reset
        2. 7.4.3.2 Power-Down
      4. 7.4.4 Conversion Control and Data Transfer Frame
        1. 7.4.4.1 Conversion Control and Data Transfer Frame With Zero Cycle Latency (Zone 1 Transfer)
        2. 7.4.4.2 Conversion Control and Data Transfer Frame With Wide Read Cycle (Zone 2 Transfer)
    5. 7.5 READY/STROBE Output
      1. 7.5.1 READY Output
      2. 7.5.2 STROBE Output
    6. 7.6 Programming
      1. 7.6.1 Output Data Word
      2. 7.6.2 Data Transfer Protocols
        1. 7.6.2.1 Protocols for Reading From the Device
          1. 7.6.2.1.1 Legacy, SPI-Compatible Protocols (SPI-xy-S-SDR)
          2. 7.6.2.1.2 SPI-Compatible Protocols With Bus Width Options and Single Data Rate (SPI-xy-D-SDR and SPI-xy-Q-SDR)
          3. 7.6.2.1.3 SPI-Compatible Protocols With Bus Width Options and Double Data Rate (SPI-x1-S-DDR, SPI-x1-D-DDR, SPI-x1-Q-DDR)
          4. 7.6.2.1.4 Clock Re-Timer (CRT) Protocols (CRT-S-SDR, CRT-D-SDR, CRT-Q-SDR, CRT-S-DDR, CRT-D-DDR, CRT-Q-DDR)
          5. 7.6.2.1.5 Parallel Byte Protocols (PB-xy-AB-SDR, PB-xy-AA-SDR)
        2. 7.6.2.2 Device Setup
          1. 7.6.2.2.1 Single Device: All Enhanced-SPI Options
          2. 7.6.2.2.2 Single Device: Minimum Pins for a Standard SPI Interface
        3. 7.6.2.3 Protocols for Configuring the Device
      3. 7.6.3 Reading and Writing Registers
    7. 7.7 Register Maps
      1. 7.7.1 ADS92x4R Registers
        1. 7.7.1.1 DEVICE_STATUS Register (Offset = 0h) [reset = 0h]
          1. Table 12. DEVICE_STATUS Register Field Descriptions
        2. 7.7.1.2 POWER_DOWN_CFG Register (Offset = 1h) [reset = 0h]
          1. Table 13. POWER_DOWN_CFG Register Field Descriptions
        3. 7.7.1.3 PROTOCOL_CFG Register (Offset = 2h) [reset = 0h]
          1. Table 14. PROTOCOL_CFG Register Field Descriptions
        4. 7.7.1.4 BUS_WIDTH Register (Offset = 3h) [reset = 0h]
          1. Table 15. BUS_WIDTH Register Field Descriptions
        5. 7.7.1.5 CRT_CFG Register (Offset = 4h) [reset = 0h]
          1. Table 16. CRT_CFG Register Field Descriptions
        6. 7.7.1.6 OUTPUT_DATA_WORD_CFG Register (Offset = 5h) [reset = 0h]
          1. Table 17. OUTPUT_DATA_WORD_CFG Register Field Descriptions
        7. 7.7.1.7 DATA_AVG_CFG Register (Offset = 6h) [reset = 0h]
          1. Table 18. DATA_AVG_CFG Register Field Descriptions
        8. 7.7.1.8 REFBY2_OFFSET Register (Offset = 7h) [reset = 0h]
          1. Table 19. REFBY2_OFFSET Register Field Descriptions
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 ADC Input Driver
        1. 8.1.1.1 Charge-Kickback Filter
      2. 8.1.2 Input Amplifier Selection
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Signal Path
      2. 10.1.2 Grounding and PCB Stack-Up
      3. 10.1.3 Decoupling of Power Supplies
      4. 10.1.4 Reference Decoupling
      5. 10.1.5 Differential Input Decoupling
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Development Support
    2. 11.2 Related Documentation
    3. 11.3 Related Links
    4. 11.4 Receiving Notification of Documentation Updates
    5. 11.5 Community Resources
    6. 11.6 Trademarks
    7. 11.7 Electrostatic Discharge Caution
    8. 11.8 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

8.1.1 ADC Input Driver

The input driver circuit for a high-precision ADC mainly consists of two parts: a driving amplifier and a charge kickback filter. The amplifier is used for signal conditioning of the input signal and the low output impedance of the amplifier provides a buffer between the signal source and the switched-capacitor inputs of the ADC. The charge kickback filter helps attenuate the sampling charge injection from the switched-capacitor input stage of the ADC, and band-limits the wideband noise contributed by the front-end circuit. Careful design of the front-end circuit is critical to meet the linearity and noise performance of the ADS92x4R.