SLUU420A May   2010  – February 2022 TPS51217

 

  1.   Trademarks
  2. 1 Description
    1. 1.1 Typical Applications
    2. 1.2 Features
  3. 2 Electrical Performance Specifications
  4. 3 Schematic
  5. 4 Test Setup
    1. 4.1 Test Equipment
      1. 4.1.1 Voltage Source
      2. 4.1.2 Multimeters
      3. 4.1.3 Pulse Generator
      4. 4.1.4 Output Load
      5. 4.1.5 Oscilloscope
      6. 4.1.6 Fan
      7. 4.1.7 Recommended Wire Gauge
    2. 4.2 Recommended Test Setup
      1. 4.2.1 Input Connections
      2. 4.2.2 Output Connections
      3. 4.2.3 Other Connections
    3. 4.3 List of Test Points
  6. 5 Test Procedure
    1. 5.1 Line/Load Regulation and Efficiency Measurement Procedure
    2. 5.2 Dynamic Output Voltage Transition Measurement Procedure
    3. 5.3 Equipment Shutdown
  7. 6 Performance and Typical Characteristic Curves
    1. 6.1 Efficiency
    2. 6.2 Load Regulation
    3. 6.3 Line Regulation
    4. 6.4 Transient Response
    5. 6.5 Output Ripple
    6. 6.6 Switch-Node Voltage
    7. 6.7 Start and Stop
    8. 6.8 Dymamic Output Voltage Transitions
  8. 7 EVM Assembly Drawing and PCB Layouts
  9. 8 List of Materials
  10. 9 References
  11. 10Revision History

4.1.5 Oscilloscope

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

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

Test points TP7 and TP8 can be used to measure the output ripple voltage by placing the oscilloscope probe tip through TP7 and holding the ground barrel TP8 as shown in Figure 4-1. Using a leaded ground connection can induce additional noise due to the large ground loop.

GUID-E775F1C6-A14F-4B6C-B6C9-685769B09860-low.gifFigure 4-1 Tip and Barrel Measurement for Output Voltage Ripple