Intel WiFi Link 5100 Design Manual page 14

2. Define a target local ambient temperature, T
3. Use Equation 1
needed to cool the device.
The following provides an example of how you might determine the appropriate
performance targets.
Assume:
• TDP = 25.0 W and T
• Local processor ambient temperature, T
Then the following could be calculated using
configuration.
To determine the required heatsink performance, a heatsink solution provider would
need to determine Ψ
configuration. If the heatsink solution were designed to work with a TIM material
performing at Ψ
the heatsink is as follows.
If the local ambient temperature is relaxed to 45 °C, the same calculation can be
carried out to determine the new case-to-ambient thermal resistance.
It is evident from the above calculations that a reduction in the local ambient
temperature has a significant effect on the case-to-ambient thermal resistance
requirement. This effect can contribute to a more reasonable thermal solution including
reduced cost, heatsink size, heatsink weight, and a lower system airflow rate.
®
Intel 5100 Memory Controller Hub Chipset for Communications, Embedded, and Storage Applications
TDG
14
and Equation 2
= 105 °C
CASE
T –
CASE
- - - - - - - - - - - - - - - - - - - - - - - - -
Ψ
=
CA
TDP
performance for the selected TIM and mechanical load
CS
≤ 0.20 °C/W, solving from
CS
Ψ Ψ Ψ
= –
SA CA
T
CASE
- - - - - - - - - - - - - - - - - - - - - - - - -
Ψ
=
CA
TDP
.
LA
to determine the required thermal performance
, = 60 °C
LA
Equation 1 for the given chipset
T
105 60 –
LA
- - - - - - - - - - - - - - -
=
25
Equation 2, the performance needed from
= 1.8 0.20 – =
CS
– T
105 45 –
LA
- - - - - - - - - - - - - - -
=
25
®
Intel 5100 MCH Chipset
⁄
= 1.8°C W
⁄
1.6°C W
C
- - - -
= 2.4°
W
July 2008
Order Number: 318676-003US