SBASB82 May   2025 ADS9127 , ADS9128 , ADS9129

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1  Absolute Maximum Ratings
    2. 5.2  ESD Ratings
    3. 5.3  Recommended Operating Conditions
    4. 5.4  Thermal Information
    5. 5.5  Electrical Characteristics
    6. 5.6  Timing Requirements
    7. 5.7  Switching Characteristics
    8. 5.8  Timing Diagrams
    9. 5.9  Typical Characteristics: All Devices
    10. 5.10 Typical Characteristics: ADS9129
    11. 5.11 Typical Characteristics: ADS9128
    12. 5.12 Typical Characteristics: ADS9127
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Analog Inputs
      2. 6.3.2 Analog Input Bandwidth
      3. 6.3.3 ADC Transfer Function
      4. 6.3.4 Reference Voltage
      5. 6.3.5 Temperature Sensor
      6. 6.3.6 Data Averaging
      7. 6.3.7 Digital Down Converter
      8. 6.3.8 Data Interface
        1. 6.3.8.1 Data Frame Width
        2. 6.3.8.2 Synchronizing Multiple ADCs
        3. 6.3.8.3 Test Patterns for Data Interface
          1. 6.3.8.3.1 Fixed Pattern
          2. 6.3.8.3.2 Alternating Test Pattern
          3. 6.3.8.3.3 Digital Ramp
      9. 6.3.9 ADC Sampling Clock Input
    4. 6.4 Device Functional Modes
      1. 6.4.1 Reset
      2. 6.4.2 Power-Down Options
      3. 6.4.3 Normal Operation
      4. 6.4.4 Initialization Sequence
    5. 6.5 Programming
      1. 6.5.1 Register Write
      2. 6.5.2 Register Read
      3. 6.5.3 Multiple Devices: Daisy-Chain Topology for SPI Configuration
        1. 6.5.3.1 Register Write With Daisy-Chain
        2. 6.5.3.2 Register Read With Daisy-Chain
  8. 7 Register Map
    1. 7.1 Register Bank 0
    2. 7.2 Register Bank 1
    3. 7.3 Register Bank 2
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Data Acquisition (DAQ) Circuit for a ≤20kHz Input Signal Bandwidth
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curves
      2. 8.2.2 Data Acquisition (DAQ) Circuit for a ≤100kHz Input Signal Bandwidth
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Application Curves
      3. 8.2.3 Data Acquisition (DAQ) Circuit for a ≤1MHz Input Signal Bandwidth
        1. 8.2.3.1 Design Requirements
        2. 8.2.3.2 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Related Documentation
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information
    1. 11.1 Mechanical Data

6.3.4 Reference Voltage

The ADS912x has a precision, low-drift voltage reference internal to the device. For best performance, filter the internal reference noise (as shown in Figure 6-2) by connecting a 10µF ceramic bypass capacitor to the REFIO pin. As shown in Figure 6-3, connect an external reference at the REFIO pin. When using an external reference, disable the internal reference voltage by writing PD_REF = 1b in address 0xC1 of register bank 1.

ADS9127 ADS9128 ADS9129 Internal Reference VoltageFigure 6-2 Internal Reference Voltage
ADS9127 ADS9128 ADS9129 External Reference VoltageFigure 6-3 External Reference Voltage