SBAU439 January   2024

 

  1.   1
  2.   Description
  3.   Get Started
  4.   Features
  5.   Applications
  6.   6
  7. 1Evaluation Module Overview
    1. 1.1 Introduction
    2. 1.2 Kit Contents
    3. 1.3 Specification
    4. 1.4 Device Information
  8. 2Hardware
    1. 2.1 Analog Interface
      1. 2.1.1 ADC Channel Inputs
        1. 2.1.1.1 High-bandwidth, Fully-Differential Circuit: THS4551
        2. 2.1.1.2 Precision, High-CMRR Circuit: PGA855
      2. 2.1.2 Voltage Reference
    2. 2.2 Power Supplies
      1. 2.2.1 USB Power and When to Power the Board Externally
    3. 2.3 Digital Interface and Clock Inputs
      1. 2.3.1 Digital Interface Connections
      2. 2.3.2 Clock Select
    4. 2.4 ADS9227EVM Quick Start Guide
  9. 3Software
    1. 3.1 ADS9227EVM Software Reference
      1. 3.1.1 ADS9227EVM-GUI Software Installation
      2. 3.1.2 USB Driver Installation
      3. 3.1.3 Using the CONFIG Tab
      4. 3.1.4 Using the Capture Tab
      5. 3.1.5 Using the INL/DNL Tool
      6. 3.1.6 Using the Histogram Tab
  10. 4Hardware Design Files
    1. 4.1 Schematics
    2. 4.2 PCB Layout
    3. 4.3 Bill of Materials (BOM)
  11. 5Additional Information
    1.     Trademarks
  12. 6Related Documentation

2.1.1 ADC Channel Inputs

Each ADC channel in the ADS9227 features an integrated, high-speed ADC driver amplifier. This internal driver circuit is specifically designed to charge the internal sample-and-hold capacitor in each ADC channel such that the sampled voltage is fully settled during the minimum acquisition period. In addition, the driver amplifiers present a high input impedance to the external signal chain. This allows systems engineers to design an analog input circuit that meets the requirements of the application without also being concerned with performance degradation due to charge-kickback during sampling.

The ADS9227EVM presents two unique signal chain proposals for the user to evaluate: a high-bandwidth, fully-differential circuit that supports input frequencies up to 1MHz and a low-bandwidth, high-CMRR circuit with programmable gain that supports input frequencies up to 300kHz. Either circuit can be used to drive ADC A and ADC B since the channels are identical by design in the ADS9227.