AMD-K6 Datasheet, PDF (279/346 Pages) Advanced Micro Devices – AMD-K6 Processor

20695H/0—March 1998
Preliminary Information
AMD-K6^® Processor Data Sheet
The following example calculates the required thermal
resistance of a heatsink:
If:
T_C = 70°C
T_A = 45°C
P_MAX = 20.0W at 200MHz
Then:
θ_CA
≤



T_{----PC---M--–--A--}T_{-X---A- }
=
---²---⁵----^°---^C----
20.0W
=
1.25 ^{(°C ⁄ W)}
Thermal grease is recommended as interface material because
it provides the lowest thermal resistance (≅ 0.20°C/W). The
required thermal resistance (θ_SA) of the heatsink in this
example is calculated as follows:
θ_SA = θ_CA – θ_IF = 1.25 – 0.20 = 1.05 (°C/W)
Heat Dissipation Path
Figure 93 illustrates the processor’s heat dissipation path. Most
of the heat generated by the processor is dissipated from the
top surface (ceramic and lid) of the package. The small amount
of heat generated from the bottom side of the processor where
the processor socket blocks the convection can be safely
ignored.
Ambient Temperature
Case temperature
Thin Lid
Figure 93. Processor Heat Dissipation Path
Chapter 17
Thermal Design
261