Differential pairs

[filipswit]

Based on Saturn:

Class	Plane	Impedance
MGT	External	95
	Internal	86
LVDS	External	96
	Internal	93

• [x] Generally there are missing vias connecting reference planes.

• [x] Helper_DCXO could be improved by omission Mid-2 layer (blue one)

• [x] AMC_GT.GT0TX kind of right angle

• [x] GT16TX can be straighten

• [x] MEZZ0_LVDS5 aren't well coupled

• [x] MEZZ0_LVDS6 right angle

[filipswit]

Looks like these signals on botom layer don't have solid reference plane under them.

[gkasprow]

we don't really care about power plane below user IO lines.