Making the Connection Key To Accurate Test Data

Focus:

The cables and connectors you’re using to connect your power supply to your circuit under test (as well as the cables you use to take measurements) often contribute inductance and capacitance that influence your measurement results. This brief article looks at some of the more commonly used cables such as Ethernet, USB, coax (RG58, RG174, RG6, and Tempflex low inductance), line cord, and twisted pair as well as banana-to-miniclip test leads. Using a vector network analyzer, the authors measure cable impedance, present normalized results, and discuss them. This includes discussion of some cable-related effects such as oscillations on the input of switching regulators, jitter on the output of high-speed clocks, and degraded ADC performance. The article concludes with advice on how to select the right cable for a particular measurement with Bode plots measurements used as an example.

What you’ll learn:

• How to understand the impact of inductance and capacitance in power supply and other cables on circuit measurements

View the Source

Author & Publication:

Steve Sandler, Charles Hymowitz, and Tom Boehler, Picotest, Power Electronics Technology, Jun 01 2012

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