SBAU436A January   2024  – February 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 EVM Analog Input Options
      1. 2.1.1 Differential SMA Inputs
      2. 2.1.2 Single-Ended SMA Inputs
      3. 2.1.3 Differential Input Pins
    2. 2.2 Power Supplies
    3. 2.3 ADC Connections and Decoupling
    4. 2.4 ADC Input Amplifiers
    5. 2.5 VCOM Buffer
    6. 2.6 Voltage Reference
    7. 2.7 Clock Tree
    8. 2.8 Digital Interfaces
  9. 3Software
    1. 3.1 ADS1278EVM Software Installation
  10. 4Implementation Results
    1. 4.1 Hardware Connections
    2. 4.2 Optional EVM Configuration
    3. 4.3 GUI Settings for ADC Control
    4. 4.4 Time Domain Display
    5. 4.5 Frequency Domain Display
    6. 4.6 Histogram Display
  11. 5Hardware Design Files
    1. 5.1 Schematics
    2. 5.2 PCB Layouts
    3. 5.3 Bill of Materials (BOM)
  12. 6Additional Information
    1. 6.1 Trademarks
  13. 7References
  14. 8Revision History

2.6 Voltage Reference

Figure 3-7 shows the REF5025 configuration. The OPA2320 buffer circuit drives the ADS1278 reference input pins. The reference voltage can optionally be provided through the J2 VREFext header pins (depopulated by default) by depopulating jumper resistor R22. Create a low pass filter by replacing the components connecting the buffer to the ADS1278 (R18, C10, R20). Use test points VREFP and VREFN to read back the reference voltage provided to the filter.

GUID-20231113-SS0I-SLCZ-MFB7-GG5CHNQ1RLVV-low.svgFigure 2-7 Reference Voltage Circuit