TIDUF45 May   2024

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
    1. 1.1 Key System Specifications
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
    3. 2.3 Highlighted Products
      1. 2.3.1 ADS127L21
      2. 2.3.2 PGA855
      3. 2.3.3 REF70
  9. 3System Design Theory
  10. 4Hardware, Software, Testing Requirements, and Test Results
    1. 4.1 Hardware Description
      1. 4.1.1 Board Interface
      2. 4.1.2 Power Supplies
      3. 4.1.3 Clocking Tree
    2. 4.2 Software Requirements
    3. 4.3 Test Setup
    4. 4.4 Test Results
      1. 4.4.1 DC Accuracy Tests
      2. 4.4.2 Gain and Offset Temperature Drift
      3. 4.4.3 Nonlinearity
      4. 4.4.4 SNR and Noise Performance
  11. 5Design and Documentation Support
    1. 5.1 Design Files
      1. 5.1.1 Schematics
      2. 5.1.2 BOM
    2. 5.2 Software
    3. 5.3 Documentation Support
    4. 5.4 Support Resources
    5. 5.5 Trademarks
  12. 6About the Author

4.3 Test Setup

Use the basic setup in Figure 4-3 to evaluate the PCB. The board is evaluated through the PHI board to a PCB running the ADS127L21EVM-PDK-GUI software. The default reference value in the GUI is 2.5V, which must be updated to 4.096V.

The following components are required to run all tests:

  • Reference Design PCB
  • PHI board
  • PC running the ADS127L21 software
  • ± 15V power supplies
  • Low noise DC source
  • 6.5 digit digital multimeter
  • For temperature drift measurements: temperature chamber
TIDA-010945 Test Setup for DC AccuracyFigure 4-3 Test Setup for DC Accuracy

Connect the hardware and power on as shown in Figure 4-3.

Use twisted pairs or SMA connectors to connect the precision DC source to the input of the signal chain, using the shortest connections possible. This reduces the amount of noise coupled into the signal chain, allowing for high-accuracy measurements.

To test a single-ended signal, connect the negative input (AINN) directly to ground using jumper J17 and connect the desired signal to the positive input (AINP) using the SMA connector (J19) or one of the pin connectors (J18 pin 2, or J20 pin 1).