SBAU491 May   2025 ADS9326 , ADS9327

 

  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 ADS9327EVM Quick Start Guide
    2. 2.2 Analog Interface
      1. 2.2.1 Fully-Differential Circuit: THS4552
      2. 2.2.2 Voltage Reference
    3. 2.3 Power Supplies
      1. 2.3.1 USB Power and When to Power the Board Externally
  9. 3Software
    1. 3.1 Digital Interface and Clock Inputs
      1. 3.1.1 Digital Interface Connections
      2. 3.1.2 Clock Select
    2. 3.2 ADS9327EVM Software Reference
      1. 3.2.1 ADS9327EVM-GUI Software Installation
      2. 3.2.2 Using the CONFIG Tab
      3. 3.2.3 Using the Capture Tab
      4. 3.2.4 Using the INL/DNL Tool
  10. 4Hardware Design Files
    1. 4.1 Schematics
    2. 4.2 PCB Layout
    3. 4.3 Bill of Materials (BOM)
  11. 5Additional Information
    1. 5.1 Trademarks
  12. 6Related Documentation

2.2.2 Voltage Reference

The ADS9327 uses an internal 4.096V reference voltage when AVDD = 5V and an internal reference voltage of 2.5V when AVDD = 3.3V, which is measurable 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 ADS9327EVM includes 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 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 ADS9327, configure the REFIO pin as an input through the GUI and then install a shunt on jumper J2 in the [1-2] position.

ADS9327EVM External Reference Voltage Using REF7040Figure 2-4 External Reference Voltage Using REF7040