Intel CELERON 200 User Manual download pdf (Page 27)

Thermal Metrology

Thermal and Mechanical Design Guidelines 27

3 Thermal Metrology

This section discusses guidelines for testing thermal solutions, including measuring

processor temperatures. In all cases, the thermal engineer must measure power

dissipation and temperature to validate a thermal solution. To define the performance

of a thermal solution the “thermal characterization parameter”, Ψ (“psi”) will be used.

3.1 Characterizing Cooling Performance

Requirements

The idea of a “thermal characterization parameter”, Ψ (“psi”), is a convenient way to

characterize the performance needed for the thermal solution and to compare thermal

solutions in identical situations (same heat source and local ambient conditions). The

thermal characterization parameter is calculated using total package power.

Note: Heat transfer is a three-dimensional phenomenon that can rarely be accurately and

easily modeled by a single resistance parameter like Ψ.

The junction-to-local ambient thermal characterization parameter value (Ψ

) is used

as a measure of the thermal performance of the overall thermal solution that is

attached to the processor package. It is defined by the following equation, and

measured in units of °C/W:

Equation 2 Ψ

= (T

– T

) / P

Where:

= Junction-to-local ambient thermal characterization parameter (°C/W)

= Processor junction temperature (°C)

= Local ambient temperature in chassis at processor (°C)

= Processor total power dissipation (W) (assumes all power dissipates

through the processor die)

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Intel CELERON 200 User Manual Page 27