I see this question has been asked many different ways but looking for best recommendation for connecting two PHYs (DP83867's) board to board across a backplane (just a few inches)? I could go transformerless, 1 transformer or 2 transformers since board space is not an issue.
Which is best for 1000BASE (1GbE) operation.
1) transformerless (capacitive coupled)
2) 1 transformer (single transformer between the PHYs center tap with decoupling cap on each side)
3) 2 transformers (2 transformers back to back with center tap decoupling cap on phy side, 50ohm termination in between)