How Much Bandwidth Does a High-speed Differential Pair Require?

Watch Lee Ritchey of Speeding Edge as he discusses high-speed differential pairs. Topics addressed in this video include:

  • A description of the two basic logic signaling protocols—single-ended logic paths and differential signaling paths and how these two protocols are very different.
  • How single-ended logic paths have inputs that respond to the rising and falling edges of logic signals and must pass several higher harmonics of the clock frequency in order to preserve logic precision.
  • In contrast, with differential signaling paths, rise times are not so important. What is important is the precision with which the two signals cross. Ideally, the two wave forms are a perfect sine wave—often referred to as an eye diagram.
  • How differential signals don’t have to pass more than the first harmonic of a clock for a differential link to do its job and are therefore preferable over single-ended logic paths.