Intel® 820E Chipset
R
40 Design Guide
Figure 19. Incorrect Direct RDRAM* Ground Plane Referencing
3.3-V Plane
1.8-V Plane
MCH

Wrong

dir_Rambus_gnd_plane_ref_incorrect
RIMM2
RIMM1
Figure 20. Direct RDRAM* Ground Plane Reference
Extend GND plane
reference island beyond
V
TERM
capacitors
GND Plane 1.8-V Plane
RIMM1
GND PlaneGND Plane
MCH
Required
Vterm layer not shown
V
TERM
resistors
V
TERM
capacitors
dir_Rambus_gnd_plane_ref
RIMM2

3.3-V Plane

The ground reference island under the RSL signals MUST b e connected to the ground pins on the RIMM
connector and the ground vias used to connect the ground isolation on the first and fourth layers.