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

2.1.2 Voltage Reference

The ADS9227 uses an internal 4.096V reference voltage, which can be measured on the REFIO pin when configured as an output (default). For applications which require improved drift performance, configure the REFIO pin as an input and apply an external reference voltage to the pin.

The ADS9227EVM include a provision for evaluating the REF7040 reference IC. The REF70xx family of high precision series voltage references offers the industry’s lowest noise (0.23ppmp-p), very low temperature drift coefficient (2ppm/°C), and high accuracy (±0.025%). In addition, these precision reference devices feature high PSRR, low drop-out voltage and excellent load and line regulation to help meet strict transient requirements. The REF7040 on the EVM is the 4.096V output voltage option. To connect the REF7040 to the ADS9227, configure the REFIO pin as an input via the GUI and then install a shunt on jumper JP2 in the [1-2] position.

GUID-20240117-SS0I-V4D7-FJH7-XMMXDPVVX21T-low.svg Figure 2-4 External Reference Voltage Using REF7040