SLVU192B February   2007  – January 2022 TPS40077

 

  1.   Trademarks
  2. 1Introduction
    1. 1.1 Description
    2. 1.2 Applications
    3. 1.3 Features
  3. 2TPS40077EVM-001 Electrical Performance Specifications
  4. 3Schematic
    1. 3.1 Adjusting Output Voltage (R3 and R13)
    2. 3.2 Disable (J3)
    3. 3.3 Test Set Up
      1. 3.3.1 Equipment
        1. 3.3.1.1 Voltage Source
        2. 3.3.1.2 Meters
        3. 3.3.1.3 Loads
        4. 3.3.1.4 Oscilloscope
        5. 3.3.1.5 Recommended Wire Gauge
    4. 3.4 Equipment Setup
      1. 3.4.1 Procedure
      2. 3.4.2 Diagram
    5. 3.5 Start-Up/Shut Down Procedure
    6. 3.6 Control Loop Gain and Phase Measurement Procedure
    7. 3.7 Equipment Shutdown
  5. 4TPS40077EVM Typical Performance Data and Characteristic Curves
    1. 4.1 Efficiency
    2. 4.2 Line and Load Regulation
    3. 4.3 Output Ripple
    4. 4.4 Transient Response
    5. 4.5 Bode Plot
  6. 5EVM Assembly Drawings and Layout
  7. 6List of Materials
  8. 7Revision History

3.3.1.4 Oscilloscope

A digital or analog oscilloscope can be used to measure the ripple voltage on VOUT. The oscilloscope should be set to the following to measure output ripple:

  • 1-MΩ impedance
  • 20-MHz bandwidth
  • AC coupling
  • 1-μs/division horizontal resolution
  • 20-mV/division vertical resolution

TP9 and TP10 can be used to measure the output ripple voltage by placing the oscilloscope probe tip through TP9 and holding the ground barrel to TP10 as shown in Figure 3-2. For a hands-free approach, the loop in TP10 can be cut and opened to cradle the probe barrel. Using a leaded ground connection must be avoided because it induces additional noise due to its large ground-loop area.

GUID-4C7BDA5D-3CB5-4B5C-AD58-4983EE2CADFD-low.gifFigure 3-2 Output Ripple Measurement – Tip and Barrel Using TP9 and TP10