SBAU251B July   2017  – February 2023 ADS8331 , ADS8332

 

  1.   ADS8332EVMV2-PDK User's Guide
  2.   Trademarks
  3. 1Overview
    1. 1.1 ADS8332EVMV2-PDK Features
    2. 1.2 ADS8332EVMV2 Features
  4. 2EVM Analog Interface
    1. 2.1 ADS8332EVMV2 Onboard Reference
  5. 3Digital Interfaces
    1. 3.1 ADS8332 Digital Interface
  6. 4Power Supplies
  7. 5ADS8332EVMV2-PDK Initial Setup
    1. 5.1 Default Jumper Settings
    2. 5.2 EVM Graphical User Interface (GUI) Software Installation
  8. 6ADS8332EVMV2-PDK Operation
    1. 6.1 EVM GUI Global Settings for ADC Control
    2. 6.2 Time Domain Display Tool
    3. 6.3 Spectral Analysis Tool
    4. 6.4 Histogram Tool
    5. 6.5 Linearity Analysis Tool
    6. 6.6 Input Amplifier Configurations
  9. 7Bill of Materials, PCB Layout, and Schematics
    1. 7.1 Bill of Materials
    2. 7.2 PCB Layout
    3. 7.3 Schematics
  10. 8Revision History

6.3 Spectral Analysis Tool

The spectral analysis tool, shown in Figure 6-6, is intended to evaluate the dynamic performance (SNR, THD, SFDR, SINAD, and ENOB) of ADS8332 SAR ADC through single-tone sinusoidal signal FFT analysis using the 7-term Blackman-Harris window setting.

GUID-0DDA6B29-B4BF-4C84-B839-EBCBB2584CD5-low.pngFigure 6-6 Spectral Analysis Tool

For dynamic performance evaluation, the external single-ended source must have better specifications than the ADS8332 to make sure that the measured system performance is not limited by the performance of the signal source. Therefore, the external reference source must meet the source requirements mentioned in Table 6-1.

Table 6-1 External Source Requirements for Evaluation of the ADS8332
Specification Description Specification Value
Signal frequency 2 kHz (OSR=0)
External source type Single-ended
External source common-mode 2.048 V
Maximum SNR 100 dB
Maximum THD –110 dB

For 2-kHz SNR and ENOB evaluation at a maximum throughput of 500 kSPS, the optimal number of samples is 32768. More samples brings the noise floor so low that the external source phase noise can dominate the SNR and ENOB calculations.

Finally, the FFT tool includes windowing options that are required to mitigate the effects of noncoherent sampling (this discussion is beyond the scope of this document). The 7-Term Blackman Harris window is the default option and has sufficient dynamic range to resolve the frequency components of up to a 24-bit ADC. The None option corresponds to not using a window (or using a rectangular window) and is not recommended.