We are using the 75LBC172, running at 15Mbps. We are driving about 4m of shielded 100 ohm cable, with multiple loads at the end. 100 ohms resistor termination at both ends of the cable, but not on the very short stub loads near the far end. We are seeing too much common mode noise generated by the driver, because the driver output delay high-to-low is about 2ns faster then the driver output delay low-to-high. Both the + and - outputs show the same skew, so the common mode summation of them has a pretty good size blip induced on the cable shield.
Why is there so much skew, what can I do about it? It is causing too much EMI.
