SBASAX3A May   2025  – September 2025 ADS9326 , ADS9327

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1  Absolute Maximum Ratings
    2. 6.2  ESD Ratings
    3. 6.3  Thermal Information
    4. 6.4  Recommended Operating Conditions
    5. 6.5  Electrical Characteristics 
    6. 6.6  Electrical Characteristics: AVDD = 5V
    7. 6.7  Electrical Characteristics: AVDD = 3.3V
    8. 6.8  Timing Requirements
    9. 6.9  Switching Characteristics
    10. 6.10 Timing Diagrams
    11. 6.11 Typical Characteristics
  8. 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 Reference
        1. 7.3.2.1 Internal Reference
          1. 7.3.2.1.1 Selectable Internal Reference with 5V AVDD
        2. 7.3.2.2 External Reference
        3. 7.3.2.3 External Reference With External Reference Buffer
      3. 7.3.3 ADC Transfer Function
      4. 7.3.4 Data Interface
      5. 7.3.5 Programmable Data Averaging Filter
        1. 7.3.5.1 Simple Average
          1. 7.3.5.1.1 Simple Average with Noncontinuous CONVST
        2. 7.3.5.2 Moving Average
      6. 7.3.6 CRC on Output Data Interface
      7. 7.3.7 ADC Output Data Randomizer
      8. 7.3.8 Data Frame Width
      9. 7.3.9 Daisy-Chain Mode
        1. 7.3.9.1 Daisy-Clock Mode
    4. 7.4 Device Functional Modes
      1. 7.4.1 Reset
      2. 7.4.2 Normal Operation
      3. 7.4.3 Low-Latency Mode
      4. 7.4.4 CS-CONVST Short Mode
      5. 7.4.5 Register Read Mode
      6. 7.4.6 Initialization Sequence
    5. 7.5 Programming
      1. 7.5.1 SPI Frame Length for Register Operations
      2. 7.5.2 Register Map Lock
      3. 7.5.3 Register Write
      4. 7.5.4 Register Read
  9. 8 Register Map: ADS9327
    1. 8.1 Register Bank 0
    2. 8.2 Register Bank 1
    3. 8.3 Register Bank 2
  10. 9 Register Map: ADS9326
    1. 9.1 Register Bank 0
    2. 9.2 Register Bank 1
    3. 9.3 Register Bank 2
  11. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 Analog 1VPP Sine-Cosine Encoder Interface
      2. 10.2.2 Design Requirements
      3. 10.2.3 Detailed Design Procedure
    3. 10.3 Power Supply Recommendations
    4. 10.4 Layout
      1. 10.4.1 Layout Guidelines
      2. 10.4.2 Layout Example
  12. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Support Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  13. 12Revision History
  14. 13Mechanical, Packaging, and Orderable Information
    1. 13.1 Mechanical Data

7.3.2.3 External Reference With External Reference Buffer

To improve system gain error thermal drift, power off the internal device reference buffer and connect an external, low-drift reference buffer to the device. As illustrated in Figure 7-6, connect the output of the external reference buffer to the REFIO and REF_CAP pins and power down the internal reference buffer. Make sure the connection to REF_CAP is less than 2Ω. Table 7-3 describes the sequence to power down the internal reference buffer.

Table 7-3 Sequence to Power Down the Internal Reference Buffer
FRAME NUMBER REGISTER DESCRIPTION
ADDRESS VALUE[15:0]
1 0x02 0x0002 Select register bank 1
2 0x0C 0x0300 Power down the internal reference
3 0x03 0x000B Unlock register bank 2
4 0x02 0x0008 Select register bank 2
5 0x09 0x0010 Power down the internal reference buffer
6 0x02 0x0002 Select register bank 1

ADS9326 ADS9327 External Reference With External Reference Buffer

Figure 7-6 External Reference With External Reference Buffer