User's Manual

Layout/Routing Guidelines
2-48 Intel
®
820 Chipset Design Guide
Motherboard Interfaces
Figure 2-39 shows the Hole Locations and Keepout Zones For Support Components (from the
motherboard surface to 0.100” above the motherboard surface.).
NOTES:
1. The dashed lines represent the centerlines for the connector keying features.
2. Drawing not to scale
Figure 2-40 shows the dimensions of the grounding pad needed to ground the heat sink.
NOTE: Drawing not to scale.
It is not recommended to use the GRM without the minimum size ground pads in the correct
locations. If the GRM is used without the correct pads, then there is a high risk that the metal clip
that grounds to the motherboard will be touching the solder mask on the top layer of the board, and
possibly short out traces immediately beneath the solder mask, resulting in board failure. The
required thickness of the pad is less than 0.001” (using 1/2 oz. copper).
Figure 2-39. Hole Locations and Keepout Zones For Support Components
1,2
1.270
0.806
0.232
0.231
0.375
4x ∅ 0.300 Keepout
Secondary Side
Primary Side
4.706
4.881
4x Thru
∅
0.159
+0.002
-0.001
1.038
1. All dimensions are in inches and all tolerances ±0.04, unless
otherwise specified.
2. Dash lines represent control line for connector key features when
placed on planar.
3. Retention solution not to exceed height of 2.75" off of primary
side of planar and 0.150" off of secondary side of planar.
4. Retention mechanism must stay within cross-hatch area.
0.175
5.256
Figure 2-40. Grounding Pad Dimensions for the SECC2 GRM
0.182
Ground Pad Areas,
See Detail A
Notes:
1. All dimensions are in inches and all
tolerances are ±0.004, unless otherwise
specified.
2. Retention mechanisim must stay within
Cross-Hatch area.
3. Entire specified plating area must be plated
and grounded with a minimum of eight VIAS.
Heat Sink Area
0.364
0.464
0.232
Detail A