Intel 5400 Series manual Thermal Profile, Equation 2-1.y = ax + b

Thermal/Mechanical Reference Design

2.2.5Thermal Profile

The thermal profile is a line that defines the relationship between a processor’s case temperature and its power consumption as shown in Figure 2-7. The equation of the thermal profile is defined as:

Equation 2-1.y = ax + b

Where:
y	=	Processor case temperature, TCASE (°C)
x	=	Processor power consumption (W)

a= Case-to-ambient thermal resistance, ΨCA (°C/W)

b= Processor local ambient temperature, TLA (°C)

Figure 2-7. Thermal Profile Diagram

The high end point of the Thermal Profile represents the processor’s TDP and the associated maximum case temperature (TCASE_MAX) and the lower end point represents the local ambient temperature at P = 0W. The slope of the Thermal Profile line represents the case-to-ambient resistance of the thermal solution with the y-intercept being the local processor ambient temperature. The slope of the Thermal Profile is constant, which indicates that all frequencies of a processor defined by the Thermal Profile will require the same heatsink case-to-ambient resistance.

In order to satisfy the Thermal Profile specification, a thermal solution must be at or below the Thermal Profile line for the given processor when its DTS temperature is

greater than TCONTROL (refer to Section 2.2.6). The Thermal Profile allows the customers to make a trade-off between the thermal solution case-to-ambient

resistance and the processor local ambient temperature that best suits their platform implementation (refer to Section 2.4.3). There can be multiple combinations of thermal solution case-to-ambient resistance and processor local ambient temperature that can meet a given Thermal Profile. If the case-to-ambient resistance and the local ambient temperature are known for a specific thermal solution, the Thermal Profile of that solution can easily be plotted against the Thermal Profile specification. As explained

24 Quad-Core Intel® Xeon® Processor 5400 Series TMDG