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Do Differential Pairs Need Ground? Are you sure? | Explained by Eric Bogatin

When doing PCB layout and designing boards, many people ask if GND is important for differential pair signals. Here is the answer.
  • 00:00What is this video about
  • 00:16P & N
  • 02:09Real differential pair vs. two single ended lines
  • 07:11Differential pair going through a transformer vs. ground
  • 08:35Are diff pairs routed on board different from diff pairs in cables?
  • 11:42Differential vs. common
  • 15:12What if a differential pair doesn't have any return plane - examples explained
  • 17:28Simulation of a single ended signal vs. return current path
  • 21:05Simulation differential pair signals vs. return current path
  • 24:04Tightly vs. loosely coupled differential pairs
  • 28:51Differential pairs vs. return plane far away
  • 34:03Example 1: Single ended signal in cable
  • 34:56Example 2: Single ended vs. differential signal in cable
  • 36:22Results: Impedance graphs
  • 39:51Example 3: Single ended vs. differential signal in PCB without GND plane