Intel Pentium 4 Processor in the 478-Pin Package Thermal Design Guidelines

Intel

Pentium

4 Processor in the 478-Pin Package Thermal Design Guidelines

Design Guide 43

3.2 Enabling Component Mechanical Envelope

Figure 16, Figure 17, and Figure 18 show the overall keep-out and keep-in dimensions for the

reference thermal/mechanical enabling design.

Figure 16 and Figure 17 show the motherboard keep-outs and height restrictions under the

enabling component region. Figure 18 shows the overall volumetric keep-in for the enabling

component assembly. This volumetric space encapsulates the processor, the socket, and the entire

thermal/mechanical enabling solution (for example, for the reference design this includes: fan

heatsink assembly, retention mechanism, and attach clips). The maximum allowable volume for

the fan/heatsink assembly is defined in Section 3.3.2.

Note: Pin A1 and Ball A1, as referred to in Figure 16, do not physically exist on the 478-pin package

and the 478-pin socket respectively. However, they may be used as a reference for design

purposes. Motherboard designers should focus exclusively on Ball A1 callouts to determine

position of the hole respective to the socket when working of the board layout. By design, the

processor is then centered within the hole pattern when the socket is in the closed position. Pin A1

is associated specifically with the package, and its position on the drawing Figure 16 corresponds

to the package within the socket in close position.