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

9.2.3 Detailed Design Procedure

A typical encoder with an analog 1Vpp output has a maximum signal frequency of 500kHz. The −3dB cutoff frequency of the fully differential amplifier (FDA) circuit is designed for greater than 500kHz. Thus, supporting signals up to the maximum signal frequency of the encoder output. Choose the FDA such that the FDA settles the transient switching load from the sampling capacitor of the ADC within the ADC acquisition time (tACQ).

The output of a sine-cosine encoder has a typical amplitude of 1Vpp with a maximum amplitude of 1.2Vpp. The full-scale range of the ADS932x is ±VREF, where the typical value of VREF is 4.096V. To use the input range of the ADC, the gain of the FDA circuit is set to 6.8V/V.

To improve the SNR of the signal chain, the ADS932x offers integrated averaging filters as described in the Programmable Data Averaging Filter section. The results are shown in Table 9-2, which includes the typical SNR of the circuit with different averaging window sizes.

Table 9-2 THS4552 and ADS932x Data Summary
AVERAGING WINDOW SIZE (Simple Average) OUTPUT DATA RATE (MSPS) SNR (dB) ENOB (Bits)
0 5 93.2 15.21
2 2.5 97.2 15.86
4 1.25 99.3 16.2
8 0.625 101.1 16.5
16 0.3125 103.1 16.84
32 0.15625 105.1 17.17
64 0.078125 106.5 17.4
128 0.0390625 107.1 17.5