Intel 320028-001 manual Equation 3. Maximum Allowable Resistance

Thermal Solution Requirements—Core™ 2 Duo Mobile Processors

Figure 5. Processor Thermal Characterization Parameter Relationships

TA

HEATSINK

ΨSA

ΨJA

TIM TS

TJ

Device

ΨTIM

5.1.1Calculating the Required Thermal Performance for the Intel® Core™2 Duo processor

Overall thermal performance, ΨJA, is then defined using the thermal characterization parameter:

•Define a target component temperature TJUNCTION and corresponding TDP.

•Define a target local ambient temperature, TA.

The following provides an illustration of how to determine the appropriate performance targets.

Assume:

•TDP = 35 W and TJUNCTION = 105 °C

•Local processor ambient temperature, TA = 40 °C.

Using Equation 1, the maximum allowable resistance, junction-to-ambient, is calculated as:

Equation 3. Maximum Allowable Resistance

ΨJA = TJ −TA = 105 − 40 = 1.857 o C /W

TDP 35

To determine the required heatsink performance, a heatsink solution provider would need to determine ΨCA performance for the selected TIM and mechanical load configuration. If the heatsink solution were designed to work with a TIM material performing at ΨTIM ≤ 0.50 °C/W, solving from Equation 2, the performance of the heatsink required is:

Equation 4. Required Performance of the Heatsink

ΨSA = ΨJA − ΨJS = 1.86 − 0.50 = 1.36 o C /W

	Intel® Core™ 2 Duo Mobile Processors on 45-nm process for Embedded Applications
June 2008	TDG
Order Number: 320028-001	16