SBASAX3B May   2025  – April 2026 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 Burst Sample Operation
      4. 7.3.4 ADC Transfer Function
      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 Channel Averaging
      7. 7.3.7 Common-Mode Voltage Output
      8. 7.3.8 CRC on Output Data Interface
      9. 7.3.9 ADC Output Data Randomizer
    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  Data Interface
      2. 7.5.2  Data Frame Width
      3. 7.5.3  SPI Modes
      4. 7.5.4  CONVST Inversion
      5. 7.5.5  SCLK Echo Mode
      6. 7.5.6  Daisy-Chain Mode
      7. 7.5.7  SPI Frame Length for Register Operations
      8. 7.5.8  Register Map Lock
      9. 7.5.9  Register Write
      10. 7.5.10 Register Read
  9. 8 Register Map
    1. 8.1 Register Bank 0
    2. 8.2 Register Bank 1
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Analog 1VPP Sine-Cosine Encoder Interface
      2. 9.2.2 Design Requirements
      3. 9.2.3 Detailed Design Procedure
    3. 9.3 Power Supply Recommendations
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
      2. 9.4.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Documentation Support
      1. 10.1.1 Related Documentation
    2. 10.2 Receiving Notification of Documentation Updates
    3. 10.3 Support Resources
    4. 10.4 Trademarks
    5. 10.5 Electrostatic Discharge Caution
    6. 10.6 Glossary
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information
    1. 12.1 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. Figure 7-7 shows the current drawn on the REF_CAP pin versus the differential analog input voltage with varying sample rates. 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 0x13 0x0008 Power down the internal reference buffer
4 0x02 0x0002 Select register bank 1

ADS9326 ADS9327 External Reference With External Reference Buffer

Figure 7-6 External Reference With External Reference Buffer

ADS9326 ADS9327 REF_CAP Current vs Differential Input Voltage

Figure 7-7 REF_CAP Current vs Differential Input Voltage