![](/images/backgrounds/110365/110365-12472x1.png)
Sensor Based Thermal Specification Design Guidance
Figure
Table
| ψCA at | ψCA at | ψCA at | ψCA at |
Processor TDP | DTS = | DTS = | DTS = | |
DTS = | System | System | System | |
| TCONTROL1,2 | ambient_max= | ambient_max= | ambient_max= |
|
| 40C | 45C | 50C |
|
|
|
|
|
95W(no graphic) | 0.569 | 0.354 | 0.300 | 0.248 |
|
|
|
|
|
95W(with graphic) | 0.564 | 0.343 | 0.291 | 0.238 |
|
|
|
|
|
80W (no graphic) | 0.620 | 0.364 | 0.300 | 0.238 |
|
|
|
|
|
45W(with graphic) | 0.869 | 0.413 | 0.301 | 0.191 |
|
|
|
|
|
20W(no graphic) | 3.713 | 1.875 | 1.625 | 1.375 |
|
|
|
|
|
Notes:
1.ΨCA at “DTS = Tcontrol” is applicable to systems that has Internal Trise (Troom temperature to Processor cooling fan inlet) of less than 10 °C. In case your expected Trise is grater than 10 °C a correction factor should be used as explained below. For each 1 °C Trise above 10 °C, the correction factor CF is defined as CF= 1.7 / Processor_TDP.
2.Example, For A Chassis Trise assumption of 12 °C for a 95W TDP processor. CF = 1.7/95 W = 0.018/C
For Trise > 10 C
ΨCA at Tcontrol = Value listed in Column_2 - (Trise - 10) * CF ΨCA = 0564 - (12 - 10) * 0.018 =0.528 C/W
In this case the fan speed should be set slightly higher equivalent to YCA=0.528C/W
72 | Thermal/Mechanical Specifications and Design Guidelines |