Specifications

Thermal/Mechanical Design Guide 37
Sensor Based Thermal Specification Design Guidance
5.6 Specification for Operation Where Digital Thermal
Sensor Exceeds T
CONTROL
Table 5-1 is provided as reference for the development of thermal solutions and the fan
speed control algorithm.
Notes:
1. The ambient temperature is measured at the inlet to the processor thermal solution
2. This column can be expressed as a function of T
AMBIENT
by the following equation:
Ψ
CA
= 0.19 + (43.2 - T
AMBIENT
) * 0.013
3. This column can be expressed as a function of T
AMBIENT
by the following equation:
Ψ
CA
= 0.19 + (43.2 - T
AMBIENT
) * 0.0077
4. This table is provided as a reference please consult the product specification for current values.
5. Based on the testing performed a curve was fit to the data in the form
Psi_ca = (1+a*RPM)/(b+c*RPM) where
a = 0.000762, b = 0.667637, c = 004402
§
Table 5-1. Thermal Solution Performance above T
CONTROL
T
AMBIENT
1
Ψ
CA
at
DTS = T
CONTROL
2
RPM for Ψ
CA
at
DTS = T
CONTROL
5
Ψ
CA
at
DTS = -1
3
RPM for Ψ
CA
at
DTS = -1
5
43.2 0.190 N/A 0.190 N/A
42.0 0.206 N/A 0.199 N/A
41.0 0.219 N/A 0.207 N/A
40.0 0.232 3250 0.215 N/A
39.0 0.245 2600 0.222 3500
38.0 0.258 2200 0.230 3150
37.0 0.271 1900 0.238 2400
36.0 0.284 1700 0.245 2500
35.0 0.297 1450 0.253 2500
34.0 0.310 1300 0.261 2100
33.0 0.323 1200 0.268 1900
32.0 0.336 1100 0.276 1700
31.0 0.349 1000 0.284 1650
30.0 0.362 900 0.292 1550
29.0 0.375 850 0.299 1450
28.0 0.388 800 0.307 1350
27.0 0.401 700 0.315 1250
26.0 0.414 700 0.322 1200
25.0 0.427 650 0.330 1100
24.0 0.440 600 0.338 1050
23.0 0.453 600 0.345 1000
22.0 0.466 600 0.353 950
21.0 0.479 600 0.361 900
20.0 0.492 600 0.368 900
19.0 0.505 600 0.376 850
18.0 0.519 600 0.384 800